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Oncologic Surgical Emergencies
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SURGICAL ONCOLOGY
ONCOLOGIC SURGICAL EMERGENCIES Jolle Kirpensteijn, DVM, MS, and C. Dick van Zuilen, DVM
Emergencies often occur because of an underlying oncologic problem and pose a challenge for the medical and surgical oncologist.31- 33 Many tumor-related emergencies require immediate surgical intervention but are complicated by the debilitated state of the patient or ethical concerns for the patient's ultimate prognosis. The necessity of immediate surgery is determined by the acute nature of the problem, the physical status of the patient, and the availability of alternative treatment. A decision is made in which the progression of the disease, general health status of the patient, and experience of the clinician are extremely important. These factors influence surgical morbidity and mortality, the extent of surgery, postoperative management, and overall prognosis. Thus every oncologic emergency requires a thorough evaluation and individual therapeutic approach. The surgeon often plays a central role in the diagnosis, treatment, and aftercare of the cancer patient in an emergency situation. The first step in managing the emergency is to evaluate the patient's pathophysiologic status and to eliminate immediate threats to the patient's life. The anamnesis should include previous oncologic diagnoses, procedures, and therapies. At the same time, a cursory physical examination will point out signs of life-threatening complications that should be dealt with immediately to stabilize the patient's physical functions. After stabilization, a thorough physical examination is performed and a diagnostic and therapeutic plan is formulated. Further diagnostic steps include general tests (complete blood cell count, biochemistry and clotting profiles, and urinalysis) and cancer specific tests (fine-needle aspiration, radiography, From the Department of Clinical Sciences of Companion Animals, University of Utrecht, Utrecht, Holland
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ultrasonography, computer tomography [CT], and magnetic resonance [MR] imaging scans). The timing, selection, and purpose of surgical therapy varies with the type of cancer and the site of involvement. Timing depends on whether the emergency involves (1) a patient with stable vital functions and a problem requiring surgical correction; (2) a patient with compromised vital functions and a delayed threat to life; or (3) a patient with an immediate threat to life requiring surgical correction.45 Immediate surgery is only necessary in life-threatening situations and should be accompanied by adequate supportive care. The benefits of surgical intervention in cancer patients must be weighed against the risks of surgery. Operative morbidity and mortality depend on the basic disease process, the surgical procedure, anesthesia, and the patient's general status and ability to withstand operative trauma. 34 In oncologic patients, the basic disease process and debilitated state of the patient are major determinants of operative morbidity and mortality. Surgery may alleviate clinical signs in an emergency situation, but mortality rates can be high (Fig. 1). The goal of surgery may be complete excision of the tumor for cure, palliation, cytoreduction, or simply histologic confirmation of the tumor type. Complete excision of the tumor is the hopeful goal of surgery. Palliative surgery must improve the patient's quality of life, and perhaps prolong it. The aim of cytoreduction is to decrease tumor bulk to improve the efficacy of adjunctive treatment. Cytoreduction without adjunctive therapy is of no benefit to the patient. 34• 84 Regardless of resection type, surgery should resolve the emergency situation. Postoperative management includes monitoring the return of normal physiologic functions, evaluation of wound healing, the use of adjunctive therapy, and periodic assessment for tumor recurrence and metastasis. Intensive supportive therapy is often necessary after emergency surgery and may include intravenous administration of fluids, blood, or plasma, antibiotic therapy, and nutritional support.35 Every emergency cancer patient should be evaluated individually and carefully, and the risks and benefits of therapy should be explained to the client. SPECIFIC ONCOLOGIC EMERGENCIES Pericardia! Effusions and Neoplastic Cardiac Tamponade Pathophysiology
Pericardia! effusion caused by neoplasia of the heart or pericardium may result in cardiac tamponade, a potentially life-threatening situation.4 Tamponade is the uncontrolled increase in intrapericardiac pressure that causes decreased cardiac filling and output.53 This results in signs of right heart failure because the thinner right ventricle is more susceptible to external pressure. The severity of tamponade depends on the rate of pericardia! fluid formation, the volume accumulated, and the ability of
Thorough physical examination GeneraJ diagnostic tests Cancer specific diagn . tests Minimal supportive care
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Fluid support Anubiotic therapy Corticosteroids
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Figure 1. Algorithm for decision making in oncologic surgical emergencies.
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the pericardium to stretch.67 The pericardium can contain large volumes, if the effusion develops gradually, but in acute cases small volumes cause
severe clinical signs.1o, 77 Neoplasia, primary or metastatic, were the most common cause of pericardia} effusion in a study of 42 dogs.5 Primary cardiac tumors are rare and include hemangiosarcoma/1· 40 heart base tumors,62 mesothelioma/1 and sarcoma.49 Tumors reported to metastasize to the heart or pericardium are hemangiosarcoma, lymphoma, melanoma, and mammary adenocarcinoma. 4• 69 Malignant pericardia} effusion is not common in cats and is most often caused by lymphoma.69 Clinical Presentation and Diagnosis
Clinical signs associated with acute pericardia} effusion and tamponade include lethargy, dyspnea, anorexia, collapse, abdominal distension, sudden death, exercise intolerance, and coughing. 5• 59 Most effusions develop gradually and cause signs of chronic cardiac compression, (i.e., weight loss, muffled heart sounds, jugular pulse, ascites, dyspnea, tachycardia, splenomegaly, and hepatomegaly). 77 Thoracic radiographs, electrocardiography, and ultrasonography can confirm the diagnosis.59 Pneumopericardiography can be used to detect intrapericardiac masses/0 alternatively, ultrasonography is often used to detect masses and to guide pericardiocentesis.53• 78 Pericardiocentesis under ultrasonographic and electrocardiographic guidance can be performed for both diagnostic and therapeutic purposes. An over-the-needle catheter is inserted in the right fourth to sixth intercostal space near the costochondral junction. The right side is preferred to prevent laceration of the coronary artery. After the pericardium is punctured, the catheter is advanced, the needle is removed, and all fluid is evacuated.4• 77 The pericardia} fluid should be submitted for biochemical and cytologic examination. Tumor cells are rarely found during cytologic examination of malignant effusions or, in the case of mesothelioma, are difficult to differentiate from reactive mesothelial cells.82 Surgical Therapy and Aftercare
Therapy of patients with pericardia! effusions is directed at quickly reducing intrapericardial pressure by centesis or surgical drainage. 53 Therapeutic pericardiocentesis is indicated in dogs with cardiac tamponade, but is often of short beneficial effect.Z5 Immediate surgical intervention is indicated in active intrapericardia} hemorrhage, if pericardia} distension cannot be relieved, or if clinical signs caused by intrapericardiac masses are severe. The main objective of surgery is to remove the tumor causing the effusion, but palliative pericardiectomy is indicated in selected cases. The surgical approach and procedure depends on tumor localization and tumor type and includes lateral thoracotomy or median sternotomy. Heart base tumors are slow growing and are often detected in a late stage of disease, so surgical resection is seldom possible. Pericardiectomy,
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as a palliative procedure, is a good alternative to euthanasia or repeated pericardiocentesis for these dogs and has allowed comfortable survival up to 4 years. 77 Hemangiosarcoma is commonly located on the right auricle and can be excised surgically if small. The use of a cardiovascular stapling device allows rapid and safe excision63; however, this therapy is often palliative because of concurrent metastases to the pericardium, lungs, or other distant sites. 4• 5• 40• 77 The prognosis for dogs with cardiac hemangiosarcoma is poor and comparable to involvement of other sites.21 The median survival of 15 dogs treated with vincristine, doxorubicin, and cyclophosphamide for hemangiosarcoma was 172 days38 compared with 60 days in dogs not treated with chemotherapy.40• 42 Respiratory Emergencies
Pathophysiology
Respiratory oncologic emergencies are caused by acute respiratory distress associated with tumors near or in the respiratory tract. The four most common respiratory emergencies are airway obstruction, hemorrhage, malignant pleural effusion, and superior vena cava syndrome.31 Tumor-induced airway obstruction can be caused by intraluminal masses or extraluminal compression. Intraluminal tumors can be located in the larynx, trachea, or main stem bronchi. Various types of tumors have been reported, but the incidence is relatively low. 3• 29• 37• 7°Compressive lesions are often associatedwith the thyroid (adenocarcinoma), esophagus (squamous cell carcinoma), lymph nodes (submandibular, retropharyngeal, mediastinal, or hilar), thymus (thymoma, malignant lymphoma), and other mediastinal structures.68 Primary or metastatic lung tumors are reported to cause peracute pneumothorax, hemoptysis, and hemothorax, although the incidence of these complications is low. Pleural effusion is caused by mediastinal, pleural, or pulmonary tumors that obstruct lymphatic drainage or cause inflammation, hypoalbuminemia, or hemorrhage. Malignant or tumor-induced pleural effusion can be treated effectively by closed-tube thoracostomy and rarely needs immediate surgical intervention. Superior vena cava syndrome (SVCS) is a clinical expression for obstruction of venous return from head, neck, and forelimbs caused by a process compressing the cranial vena cava. SVCS has been described in the dog but is extremely rare. 31 Theoretically, SVCS can be caused by extraluminal compression or by tumor ingrowth into the vena cava. Clinical Presentation and Diagnosis
The most common signs of tumor-induced airway obstruction are progressive dyspnea, stridor, coughing, and exercise intolerance. Most of these signs are chronic, but peracute respiratory dyspnea can develop because of hyperthermia, edema and hemorrhage related to the tumor, accumulation of secretions and debris, or laryngeal spasm. Useful diag-
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nostic procedures are laryngeal and tracheal palpation, endoscopy, radiology, ultrasonography, and cytological examination of fine-needle aspiration.29 Early diagnosis can be obtained by endoscopic-guided biopsy. Clinical signs caused by pulmonary neoplasia include coughing, dyspnea, lethargy, weight loss, tachypnea, hemoptysis, and exercise intolerance.29· 60 Thoracic radiographs and cytologic examination of percutaneous fine-needle aspirates are the most valuable diagnostic methods. Additional diagnostic testing (transtracheal lavage, ultrasonography, or bronchoscopy) are not necessary in an emergency situation for solitary lung lesions because in most cases surgical excision is the therapy of choice.83 In contrast, additional diagnostic testing can be very useful for metastatic disease or pleural effusions. Malignant pleural effusion may cause peracute clinical signs including tachypnea, dyspnea, decreased exercise intolerance, abdominal breathing, and cyanosis.28 Decreased respiratory and cardiac sounds ventrally, in combination with dullness on percussion, are pathognomonic physical findings. Definite diagnosis is made by thoracic radiography and thoracocentesis. 28· 81 Progressive dyspnea and swelling of the face, neck, and forelimbs caused by edema, are the most common signs of SVCS. The onset is often insidious, but peracute dyspnea can be seen as the disease progresses.31 Radiographs, ultrasonography, and CT scans of the cranial thorax often allow the tumor to be localized. Diagnosis of tumor type may be obtained using fine-needle aspiration or cutting biopsy needle. Surgical Therapy and Aftercare
Initial therapy for tumor-induced respiratory emergencies is identical to that for other respiratory distress syndromes and may include supplemental oxygen therapy, tracheostomy, and thoracostomy tube placement. Tumor-induced upper airway obstruction is treated by tracheostomy or tumor removal. Emergency tracheostomy is indicated for life-threatening upper respiratory obstructions, in which the condition of the patient does not allow extensive surgery, or for immediate palliation. Several methods of creating a temporary tracheostomy are described, and the procedure can often be performed on an emergency basis with minimal anesthetic restraint. 58 Complete tumor excision is the therapy of choice in benign tumors (oncocytoma, leiomyoma, and polyps) obstructing the respiratory tract and results in an excellent prognosis. If obstruction is caused by a laryngeal tumor, partial or total laryngectomy can be performed. Some pedunculated tumors can be removed via the mouth, but partial laryngectomy via ventral laryngotomy incision is necessary for larger neoplasms. 29· 83 Extensive malignant tumors of the larynx may require total laryngectomy and permanent tracheostomy. 19 To remove tracheal tumors an end-to-end tracheal anastomosis is often necessary. Four rings (12%) of the trachea can be resected easily, although in a few cases successful resection of 25% to 50% of the trachea has been reported. 29· 58 The incidence of tracheal stenosis and dehiscence increases after extensive tracheal resection because of increased longitudinal ten-
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sion.58 Chemotherapy and radiation therapy have been described.29, 70 Of the two, radiation seems to be most successful, especially for malignant lymphoma of the larynx and trachea. 29 Emergency surgical intervention is seldom necessary in dogs with pulmonary neoplasms. Pneumothorax and pleural effusions are commonly treated successfully with a thoracostomy tube. 20 Two indications for immediate surgical exploration are active hemorrhage, and a nonproductive thoracostomy tube in the presence of serious pneumothorax or pleural effusion. Exploratory thoracotomy is performed via an intercostal incision or median sternotomy. Isolated primary pulmonary masses are best treated by removal of the affected lung lobe through an intercostal thoracotomy. The use of thoracoabdominal staplers has simplified the procedure and decreased morbidity. 60 Regional lymph nodes undergo a biopsy procedure if enlarged. The prognosis is most favorable in dogs with small tumors and no lymph node involvement. More than 50% of these patients survive at least 1 year after surgery. 83 There is no proven effective therapy for canine or feline SVCS. Surgical excision of discrete mediastinal, pulmonary, or cardiac masses may eliminate clinical signs. Radiation therapy to reduce the tumor mass seems to be the therapy of choice in humans and may be beneficial in animals. 31 Hemorrhagic Abdominal Emergencies Pathophysiology
Hemorrhagic abdominal emergencies develop secondary to direct extension and ulceration of various malignant tumor types into the peritoneal cavity, or to rupture of an organ enlarged from tumor invasion. Abdominal hemorrhage is most frequently associated with splenic or hepatic tumors. The most common canine splenic tumor is hemangiosarcoma. It usually affects older animals and metastasizes in more than 50% of cases to other organs including lungs, heart, liver, kidney, omentum, and peritoneum.42' 48 Mast cell tumor and malignant lymphoma occur most frequently in the spleen of cats.65 Any enlarged spleen may rupture, resulting in internal blood loss and hypovolemic shock. 65 Primary hepatic tumors occur in older dogs and cats but are rare. Hepatocellular carcinoma is most common, and it frequently metastasizes to regional lymph nodes, lung, and peritoneum.46, 66 More common than primary hepatic tumors, metastatic tumors include malignant lymphoma, pancreatic adenocarcinoma, and hemangiosarcoma.16' 66 Massive hemorrhage can occur from any hepatic tumor and may require emergency laparotomy. 8 Clinical Presentation and Diagnosis
Abdominal hemorrhage results in abdominal enlargement, pale mucous membranes, lethargy, abdominal pain, tachycardia, tachypnea, and
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vomiting. Clinical signs vary with the severity of bleeding. In patients with exsanguinating hemorrhage, clinical signs of hypovolemic shock predominate. Once a diagnosis of abdominal effusion is made, little additional information is obtained by radiographic examination. The presence of fluid decreases the value of radiography but enhances the use of ultrasonography. Radiography after removal of fluid by abdominal paracentesis may improve visualization of intra-abdominal structures and assist in diagnosis. 24 Fluid obtained should be examined cytologically. Neoplastic cells may be identified in aspirated fluid, but neoplastic disease should not be excluded on basis of negative findings. 66 To differentiate hemorrhage from serosanguinous exudate, the packed cell volume and white blood cell counts are compared with those of peripheral blood.82 The packed cell volume of serosanguinous exudates rarely exceeds 5%.18 An increase in packed cell volume in sequential samples may indicate continuing intra-abdominal bleeding. Alternatively, intra-abdominal masses can be diagnosed by ultrasonography and guided fine-needle aspiration. Nondiagnostic samples are relatively common because of sampling errors and because little material is obtained from some tumor types. Definite diagnosis may require histologic examination of a surgical biopsy specimen. In patients with abdominal hemorrhage, clotting ability should be investigated before surgery because disturbances can be caused by the tumor. In up to 50% of dogs with splenic hemangiosarcoma, there is diffuse intravascular coagulation.38 Surgical Therapy and Aftercare
The clinical status of the patient dictates the type of treatment. An initial period of medical stabilization before surgical intervention may improve prognosis. Supportive therapy consists of intravenous fluid, hypertonic saline, or colloid therapy, blood transfusions, and pressure wraps. Blood transfusions are often necessary in dogs with exsanguinating abdominal hemorrhage. Autotransfusion, rather than heterologous blood transfusion, is contraindicated in tumor-induced abdominal hemorrhage, because it can spread tumor cells. Increased intra-abdominal pressure by application of an abdominal pressure wrap may help control hemorrhage. Compressive abdominal and pelvic bandages are the practical alternative for seldom available antishock garments. 18 Emergency laparotomy is indicated if, despite fluid and blood replacement, the animal deteriorates. 18 The abdomen should be explored thoroughly to locate the source of bleeding and to search for signs of metastases. Total splenectomy often is life saving in hemorrhaging splenic malignancies, but a cure is rarely obtained. The prognosis for dogs with a ruptured hemangiosarcoma after splenectomy is poor, because of the tumor's aggressive metastatic behavior. An average survival time of 2 months without and 6 months with adjuvant chemotherapy has been reported. 38, 42 In contrast to malignant tumors, benign splenic tumors have
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an excellent prognosis after surgical removal. The use of ligating-dividing staplers (LDS) allow expedient and safe surgical removal of hemorrhaging splenic neoplasms. 63 Surgical excision by partial or total hepatic lobectomy is the treatment of choice for bleeding hepatic tumors located in a single lobe?, 46 The prognosis for benign hepatic tumors is good, survival times of more than 2 years have been reported. 66 Malignant hepatic tumors carry a poorer prognosis,66 although lobectomy in dogs with hepatocellular adenocarcinoma resulted in a mean survival of 377 days.46
Urogenital Oncologic Emergencies Pathophysiology
Urogenital oncologic emergencies are often related to obstruction of the ureter, bladder neck, or urethra, or to hemorrhage from the tumor. Obstructive lesions can be located extramural (intra-abdominal, retroperitoneal, or intrapelvic), intramural (renal, ureteral, bladder, or urethral wall), or intraluminal. Extramural obstruction is caused by tumors in many anatomical locations including prostate (adenocarcinoma), rectum or colon (adenocarcinoma), vagina (leiomyoma or fibroma), and regional lymph node (lymphoma or metastasis)Y Intramural and intraluminal obstructions are most often caused by transitional cell carcinomas,64, 76 renal tumors,43 and benign proliferations.57 Serious and life-threatening abdominal hemorrhage and hematuria is often caused by renal tumors from direct extension of the tumor into the peritoneal or renal pelvic space. Renal tumors are usually malignant in the dog and cat, metastasize in up to 50% of cases, and most commonly affect older animals. 43 Primary renal tumors include tubular cell carcinoma, transitional cell carcinoma, fibrosarcoma, hemangiosarcoma, and nephroblastoma in the dog and lymphoma, renal carcinoma, sarcoma, and nephroblastoma in the cat. 2' 12' 36 Ureteral tumors are rare but can cause hydronephrosis. 27' 39 Bladder and urethral tumors are more common than renal or ureteral tumors and are most prevalent in female dogs and male cats. Except for rhabdomyosarcoma, bladder tumors affect older animals, and the most common tumor type in dogs and cats is transitional cell carcinoma. 12, 64, 72 Transitional cell carcinomas are highly invasive tumors that grow slowly often in the trigone area and bladder neck. Emergencies associated with bladder and urethral tumors are usually caused by obstruction of the urethra or ureter. These tumors eventually metastasize in 80% of dogs. Common sites include the lung, lumbar lymph nodes, kidney, prostate, and liver. Benign diseases must also be considered in the differential diagnosis. Chronic and acute renal failure, urinary tract infections, urolithiasis, ureteral strictures, cyclophosphamide-induced cystitis, and neurologic abnormalities could cause similar signs.
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Clinical Presentation and Diagnosis
Clinical signs depend on the location and size of the tumor. Renal and ureteral tumors are associated with hematuria, renal enlargement, abdominal pain, anorexia, depression, and weight loss.36' 43 Physical examination may show a large, painful abdominal mass, and the diagnosis is confirmed by abdominal radiography,43 ultrasonography,80 contrast studies (intravenous pyelogram)/ renal scintigraphy, CT, or MR imaging scans. Routine serum chemistry and urinalysis allows evaluation of kidney function. Ultrasonographic guided fine-needle aspiration of the tumor facilitates early diagnosis. Dysuria, hematuria, polyuria, pollakiuria, or anuria are observed with lower urinary tract tumors. 57 Neoplasms associated with the bladder and urethra may be palpated by abdominal and rectal examination. Other useful diagnostic procedures include abdominal radiography, ultrasonography, and contrast studies (intravenous pyelogram, double contrast cystogram, retrograde urethrogram). Malignant cells are seldom found in the urine sediment but may be obtained by catheter biopsy or percutaneous fine-needle aspiration of prostate and urethraY Direct cystoscopic visualization of the tumor in the bladder or urethra is often possible in female dogs, and the diagnosis is confirmed by cystoscopic biopsy. Surgical Therapy and Aftercare
Surgical therapy depends on the site of obstruction. Unilateral nephrectomy and ureterectomy are indicated for renal tumors if the opposite kidney is functional, and if metastases are not present.36• 43 Mean survival time after nephrectomy for dogs with renal tubular cell carcinoma was 7 months and for dogs with transitional cell carcinoma it was 11 months. 43 Surgical excision is the therapy of choice for cystic and urethral transitional cell carcinomas but is often impossible because of tumor location. Partial cystectomy may be successful in tumors not affecting the trigone. The tumor must be excised with a wide margin of normal tissue and the remainder of the bladder wall is inspected. Even after excision of more than 75% of the urinary bladder, function can eventually return to normal or near normal. 57 A modified "cup-patch" cystoplasty can be performed in resections of more than 80% of the bladder.71 When the trigone is involved, reimplantation of the ureters in the remaining bladder may be necessary. Total cystectomy has been combined with urinary diversion, but postoperative complications have made these salvage procedures less beneficial.3°· 50• 51• 75 Ureterocolonic anastomosis seems to be most successful of the urinary diversion techniques.54• 76 In general, survival times after surgical excision of bladder and urethral transitional cell carcinoma are limited because of recurrence or metastasis. Temporary relief can also be obtained using an indwelling urinary or prepubic cystostomy catheter.22• 23 The placement of cystostomy catheters is relatively simple and is associated with few complications and easy home management. This technique can be used in combination with adjuvant therapies or as palliation. A permanent cystostomy catheter
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eliminates the need for immediate euthanasia in dogs with advanced bladder and urethral cancer. Adjuvant radiation or chemotherapy may be indicated but has been associated with high rate of complications and tumor recurrence. There are fewer complications, and survival rates may be better in dogs treated with external-beam megavoltage radiation therapy in combination with a slowrelease biodegradable polymer containing cisplatin implanted at a distant site (SJ Withrow, personal communication 1993). Results of systemic or intravesicular administration of chemotherapy for transitional cell carcinoma have been variableY· 73 Partial response or stable disease was seen after intravenous cisplatin therapy in 9 of 12 dogs. 55 Also, the use of the nonsteroidal anti-inflammatory drug piroxicam has been beneficial in obstructive canine transitional cell carcinoma, at least for palliation.44 Complications after oncologic bladder or urethral surgery include incontinence, postoperative diuresis, pollakiuria (small bladder syndrome), and infection. Incontinence is treated with parasympathomimetic drugs (e.g., bethanechol chloride) for partially denervated bladders, adrenergic agonists (e.g., ephedrine) for low-pressure incontinence, anticholinergics (e.g., probanthine) for reflex neurogenic bladders, and sympatholytic drugs (e.g., phenoxybenzamine) for urethral spasms. Postobstructive diuresis should be compensated appropriately with intravenous fluid administration. Infection should be treated with antibiotics based on culture and sensitivity results. Gastroenterologic Emergencies
Pathophysiology
Acute gastrointestinal emergencies are caused by gastrointestinal perforation, obstruction, or intraluminal hemorrhage. Perforation occurs as a sequelae to ulceration of gastric or intestinal tumors, poor wound healing after enterotomy, chemotherapy for lymphoma and m ast cell tumors, or mast cell tumor-induced ulceration. 9 Gastrointestinal perforation quickly induces fulminant peritonitis resulting in fluid, electrolyte and protein losses, acid-base imbalances, hypoglycemia, diffuse intravascular coagulopathy, circulatory collapse, and septic shock. Gastrointestinal obstruction is caused by tumor encroachment or by adhesions from intra-abdominal masses. 31 Obstruction causes fluid and gas accumulation proximal to the site of obstruction and an increase in intraluminal pressure. Continued distension results in venous congestion, mural edema, decreased absorption, and increased secretion. Fluid and electrolytes are lost and significant vascular compromise may result in devitalization of the intestinal wall. At this point, the mucosal barrier is impaired and bacterial translocation results in progressive septic and hemodynamic shock. Intraluminal hemorrhage is commonly seen after ulceration of such tumors as mast cell tumors, gastrinomas, gastric and intestinal carcinomas, lymphoma, and metastatic tumors. 56 Gastric and intestinal tumors are relatively uncommon in dogs and
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cats and include adenocarcinoma,B· 47 leiomyoma/4• 52 leiomyosarcoma/4 malignant lymphoma/5• 16 mast cell tumor,9 polyps/4 and fibrosarcoma.U· 61 • 79 Mainly older animals are affected and adenocarcinoma is most common in dogs and lymphoma in cats.6 Relatively more nonlymphoid gastrointestinal tumors are reported in Siamese cats, Boxers, Collies, Staffordshire Bull terriers, and German shepherds compared with other breeds.6• 47• 81 More than two thirds of gastrointestinal tumors are malignant, and early metastasis to regional lymph nodes, liver, and lung in combination with ulceration are observed frequently.1 5• 47 Clinical Presentation and Diagnosis
Clinical signs associated with gastrointestinal tumors are nonspecific and include vomiting, diarrhea or constipation, anorexia, abdominal pain, ascites, and distension. 6• 11• 15• 47 Partial or total obstruction of the gastrointestinal tract is relatively common, and the mostcommon signs are protracted vomiting, abdominal pain, and abdominal distension. 26 With perforation, signs quickly progress to severe depression, dehydration, and signs of cardiovascular and septic shock. Intestinal bleeding is associated with signs of anemia, weight loss, hematemesis, hematochezia, diarrhea, and melena. 14 . Ascites, dilated intestines, solitary masses, and excessive borborygmi can be detected during physical examination. Radiography and ultrasonography allow further examination and localization of abdominal masses, ileus, or free air. 26 Diagnosis can be obtained using ultrasoundguided fine-needle or cutting biopsy of the tumor. Barium or iodine (if perforation is suspected) contrast studies may locate the tumor if plain radiography does not. Endoscopy is useful 'in locating and obtaining biopsy specimens from gastric, duodenal, colonic, and rectal tumors, but is seldom used in an emergency situation. Gastrointestinal perforation is accurately diagnosed by paracentesis or peritoneal lavage and immediate exploratory surgery is necessary if intracellular and extracellular bacteria, or foreign material are found on cytological examination. Rarely, diagnostic" peritoneal lavage may fail to demonstrate bacteria if the spillage caused by the perforation is localized. Repeat peritoneal lavage, radiography with water soluble contrast material, or exploratory surgery is indicated in these cases. Surgical Therapy and Aftercare
Severe active bleeding into the digestive tract, partial or complete obstruction, or gastrointestinal perforation necessitate emergency explorative laparotomy.8 Preoperative supportive care is directed to correcting fluid, electrolyte, and acid-base imbalances, and to treating septicemia and endotoxic shock.79 Supportive therapy may consist of blood transfusion, intravenous fluid or colloid administration, and antibiotic administration covering gram-negative and anaerobic bacteria (e.g., cephalosporins or aminoglycosides in combination with metronidazole). After routine celiot-
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omy, the abdomen is explored and the extent of gastrointestinal involvement is assessed. Regional lymph nodes and liver are inspected for possible metastasis. At this point, biopsy specimens of tumor and regional lymph nodes can be obtained and submitted for cytological and histological examination. Histologic examination of frozen sections allows immediate diagnosis in most cases. For gastric tumors, complete resection is the therapy of choice.U Because of frequent involvement of antrum and pylorus (50% of cases), partial gastrectomy as a Billroth I or II procedure is often necessary to obtain wide surgical margins. 15 Enlarged local lymph nodes undergo a biopsy procedure or are excised en-bloc. Partial gastrectomy is contraindicated in dogs with gastrointestinal lymphoma because of the diffuse nature of the disease, effective chemotherapy options, and associated complications with wound healing. Solitary lymphomatous lesions seem to respond better to surgery and adjunctive chemotherapy. 15, 16 Intestinal neoplasms are usually treated by wide surgical resection and anastomosis. A simple end-to-end anastomosis often is sufficient but more complex intestinal reconstruction is sometimes necessary. Tumors that have already metastasized may be excised effectively for palliation. Resection of regional lymph nodes and other sites of metastasis may decrease the total tumor burden enhancing the effect of adjuvant therapy. The use of serosal or omental patching at the surgery site is indicated for extensive resections or in patients with suspected impaired wound healing.17 The need for gastric or intestinal feeding tubes should be assessed before closure. Surgical placement of gastrostomy and jejunostomy feeding tubes is relatively easy and is described previously. 1 The benefits of improved nutritional status in cachectic cancer patients far outweigh the management disadvantages of surgically placed feeding tubes. General peritonitis after intestinal perforation is treated aggressively. Intraoperative cultures are obtained, and the abdominal cavity is lavaged with copious amounts of warm 0.9% saline solution. Open abdominal drainage is used in severe cases of peritonitis.85 For open abdominal drainage, the linea alba is closed with a loose simple continuous polypropylene suture pattern and the subcutis and skin are left open. A sterile bandage is placed over the wound and is changed as often as required. Periodic surgical lavage under strict aseptic conditions may be of benefit. The use of sterilized commercial diapers decreases the need of frequent bandage changes caused by fluid penetrating the outer bandage. Postoperative care includes continuing fluid and electrolyte therapy. Initially small quantities of water are offered, and if vomiting does not occur, small quantities of soft food can be fed. Anorectic animals may be force fed by nasogastric, endoscopically or surgically placed gastrostomy, or jejunostomy tubes. 1 After intestinal anastomosis, breakdown of the suture line most commonly occurs during the second and fourth day postoperatively and signs of physical deterioration during that time should be investigated.79 Nonperforating ulceration of the gastrointestinal tract directly or indirectly caused by tumors can be treated medically
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using antacids (e.g., aluminum hydroxide), histamine2 antagonists (e.g., cimetidine), coating agents (e.g., sucralfate), and proton pump inhibitors (e.g., omeprazole).56· 74 Malignant tumors of the gastrointestinal tract may benefit from adjunct chemotherapy because of their aggressive metastatic behavior.79 The effect of chemotherapy for canine gastric adenocarcinoma and canine and feline intestinal adenocarcinoma have been discouraging.l5· 81 Complete remission with survival times of 12 and 17 months were seen in two dogs with metastatic intestinal adenocarcinoma treated with surgical resection of the primary tumor and cisplatin and 5-fluorouracil chemotherapy (SO Gilson, personal communication 1994). Gastrointestinal malignant lymphoma is less responsive to chemotherapy than the multicentric type. Also, complications associated with intestinal perforation after chemotherapy should be taken into consideration. Because their aggressive metastatic behavior (up to 75%), the prognosis for gastrointestinal malignancies is guarded. 15· 26· 79 The prognosis is poor if the n.tmor is extensive, if metastasis is present, or when the tumor erodes through the serosal surface. The mean survival time of 12 dogs with malignant nonlymphoid gastrointestinal tumors that survived the first 2 weeks after surgery was 114 days without adjunctive chemotherapy.6 Mean survival of cats with resected adenocarcinoma was 15 months. 47 CONCLUSION
Surgical emergencies are relatively common in small animal cancer patients and pose a clinical and ethical challenge for the oncologist. The most common emergencies include pericardia! effusion and tamponade, respiratory distress, abdominal hemorrhage, and urogenital, or gastrointestinal obstruction or perforation. After emergency stabilization, the question of whether surgical intervention is proper and necessary needs to be answered. Immediate surgery is only indicated in life-threatening situations in which the risks versus the benefits of surgery have been weighed and should be accompanied by adequate preoperative and postoperative supportive care. ACKNOWLEDGMENT The authors thank Professor doctor F.J. van Sluijs for editing the manuscript.
References 1. Abood SK, Mauterer JV, McLoughlin MA, et a!: N utritional support of h ospitalized p atients. In Slatter D (ed): Textbook of Sm all Animal Surgery, ed 2. Philadelphia, WB Saunders, 1994, p . 63 2. Baskin GB, DePaoli A: Primary renal neoplasms in the dog. Vet Pathol14:591, 1977 3. Beaumont PR: Intratrach eal neoplasia in two cats. J Small Anim Pract 23:29, 1982
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4. Berg RJ: Surgical treatment of pericardia! diseases. In Bojrab MJ (ed): Current Techniques in Small Animal Surgery, ed 3. Philadelphia, Lea & Febiger, 1992, p. 522 5. Berg RJ, Wingfield W: Pericardia! effusion in the dog. A review of 42 cases. J Am Anim Hosp Assoc 20:721, 1984 6. Birchard SJ, Couto CG, Johnson S: Nonlymphoid intestinal neoplasia in 32 dogs and 14 cats. JAm Anim Hosp Assoc 22:533, 1986 7. Bjorling DE, Prasse KW, Holmes RA: Partial hepatectomy in dogs. Compend Contin Educ Pract Vet 7:257, 1985 8. Boothe HW: Exploratory laparotomy in small animals. Compend Contin Educ Pract Vet 12:1057, 1990 9. Bortnowski HB, Rosenthal RC: Gastrointestinal mast cell tumors and eosinophilia in two cats. JAm Anim Hosp Assoc 28:271, 1992 10. Bouvy BM, Bjorling DE: Pericardia! effusion in dogs and cats. Part II. Diagnostic approach and treatment. Compertd Contin Educ Pract Vet 13:633, 1991 11. Bright RM, Richardson DC, Hullinger RL: The stomach and pylorus. In Gourley IM, Vasseur PB (eds): General Small Animal Surgery. Philadelphia, JB Lippincott, 1985, p . 319 12. Caywood DD, Klausner JS, Walters PA: Oncology: Urinary system. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p . 2200 13. Church EM, Mehlhalff CJ, Patnaik AK: Colorectal adenocarcinoma in dogs: 78 cases (1973-1984). JAm Vet Med Assoc 191:727, 1987 14. Comer KM: Anemia as a feature of primary gastrointestinal neoplasia. Compertd Contin Educ Pract Vet 12:13, 1990 15. Couto CG: Gastrointestinal neoplasia in dogs and cats. In Kirk RW, Bonagura JD (eds): Current Veterinary Therapy XI. Philadelphia, WB Saunders, 1993, p . 595 16. Couto CG, Rutgers HC, Sherding RG, et a!: Gastrointestinal lymphoma in 20 dogs. A retrospective study. J Vet Intern Med 3:73, 1989 17. Crowe DT: The serosal patch: Clinical use in 12 animals. Vet Surg i3:29, 1984 18. Crowe DT, Bjorling DE: Body cavities and hernias. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p. 407 19. Crowe DT, Goodwin MA, Greene CE: Total laryngectomy for laryngeal mastcell tumor in a dog. JAm Anim Hosp Assoc 22:809, 1986 20. Dallman MJ, Martin RA, Roth L: Pneumothorax as the primary problem in two cases of brortchioalveolar carcinoma in the dog. JAm Anlm Hosp Assoc 24:710, 1988 21. De Madron E, Helfand SC, Strebbins KE: The use of chemotherapy for treatment of cardiac hemangiosarcoma in a dog. JAm Vet Med Assoc 190:887, 1987 22. Deihn CR, Person MW: Prepubic (suprapubic) catheterization of eight dogs with lower urinary tract disorders. JAm Anim Hosp Assoc 25:272, 1989 23. Deihn CR, Person MW, Leathers CW, et al: Prepubic (suprapubic) catheterization of the dog. JAm Anim Hosp Assoc 25:261, 1989 24. Ettinger SJ: Ascites, peritonitis, and other causes of abdominal enlargement. In Ettinger SJ (ed): Textbook of Veterinary Internal Medicine, ed 3. Philadelphia, WB Saunders, 1989, p. 131 25. Eyster GE, Gaber CE, Probst M: Cardiac disorders. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p. 886 26. Feeney OA, Klausner JS, Johnston GR: Chronic bowel obstruction caused by primary intestinal neoplasia: A report of five cases. JAm Anim Hosp Assoc 18:67, 1982 27. Font A, Closa JM, Mascort J: Ureteral leiomyoma causing abnormal micturition in a dog. J Am Anim Hosp Assoc 29:25, 1993 28. Forrester SD, Troy GC, Fossum TW: Pleural effusions: Pathophysiology and diagnostic considerations. Compend Contin Educ Pract Vet 10:121, i988 29. Fossum TW, Rogers KS: Respiratory System. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p. 2231 30. Fries CL, Binnington AG, Valli VE, eta!: Enterocystoplasty with cystectomy and subtotal intracapsular prostatectomy in the male dog. Vet Surg 20:104, 1991 31. Giger U, Gorman NT: Oncologic emergencies in small animals. Part III. Emergencies related to organs systems. Compend Contin Educ Pract Vet 6:873, 1984 32. Giger U, Gorman NT: Oncologic emergencies in small animals. Part I. Chemotherapyrelated and hematologic emergencies. Compend Contin Educ Pract Vet 6:689, 1984 33. Giger U, Gorman NT: Oncologic emergencies in small animals. Part II. Metabolic and endocrine emergencies. Compend Contin Educ Pract Vet 6:805, 1984
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34. Gilson SD, Stone EA: Principles of oncologic surgery. Compend Conlin Educ Pract Vet 12:827, 1990 35. Gilson SD, Stone EA: Management of the surgical oncology patient. Compend Contin Educ Pract Vet 12:1047, 1990 36. Goldsmid SE, Bellenger CR, Watson ADJ, et al: Renal transitional cell carcinoma in a dog. JAm Anim Hosp Assoc 28:241, 1992 37. Goodwin JK, Lawrence DT, Bellah JR, et al: A large solitary pulmonary fibrosarcoma in a cat. J Am Anim Hosp Assoc 27:327, 1991 38. Hammer AS, Couto CG, Filpi J, et al: Efficacy and toxicity of VAC chemotherapy 39. 40. 41. 42. 43.
44. 45. 46. 47. 48. 49. 50.
51. 52. 53.
54. 55.
56. 57. 58. 59. 60.
61. 62.
(Vincristine, doxorubicin, and cyclophosphamide) in dogs with hemangiosarcoma. J Vet lntern Med 5:160, 1991 Hanika C, Rebar AH: Ureteral transitional cell carcinoma in the dog. Vet Pathol 17:643, 1980 Hosgood G: Canine hemangiosarcoma. Compend Contin Educ Pract Vet 13:1065, 1991 Ikede BO, Zubaidy A, Gill CW: Pericardia! mesothelioma with cardiac tamponade in a dog. Vet Pathol 17:496, 1980 Johnson KA, Powers BE, Withrow SJ, et al: Splenomegaly in dogs. Predictors of neoplasia and survival after splenectomy. J Vet lntern Med 3:160, 1989 Klein MK, Cockerell GL, Harris CK, et al: Canine primary renal neoplasms: A retrospective review of 54 cases. JAm Anim Hosp Assoc 24:443, 1988 Knapp DW, Richardson RC, Bottoms GD, et al: Phase I trial of piroxicam in 62 dogs bearing naturally occurring tumors. Cancer Chemother Pharmacol 29:214, 1992 Kolata RJ: Surgical emergencies. In Gourley IM, Vasseur PB (eds): General Small Animal Surgery. Philadelphia, JB Lippincott, 1985, p. 65 Kosovsky JE, Manfra-Maretta S, Matthiesen DT, et al: Results of partial hepatectomy in 18 dogs with hepatocellular carcinoma. JAm Anim Hosp Assoc 25:203, 1989 Kosovsky JE, Matthiesen DT, Patnaik AK: Small intestinal adenocarcinoma in cats: 32 cases (1978-1985). JAm Vet Med Assoc 192:233, 1988 Lipowitz AJ, Blue J: Hemolymphatic system. Spleen. In Slatter D (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p. 948 MacEwen EG, Withrow SJ: Soft tissue sarcomas. In Withrow SJ, MacEwen EG (eds): Clinical Veterinary Oncology. Philadelphia, JB Lippincott, 1989, p. 167 McLoughlin MA, Walshaw R, Thomas MW, et al: Gastric conduit urinary diversion in normal dogs. Part I, upper urinary tract structure, function, and sepsis. Vet Surg 21:25, 1992 McLoughlin MA, Walshaw R, Thomas MW, et al: Gastric conduit urinary diversion in normal dogs. Part II, Hypochloremic metabolic alkalosis. Vet Surg 21:33, 1992 McPherron MA, Withrow SJ, Seim HB, III, et al: Colorectalleiomyomas in seven dogs. JAm Anim Hosp Assoc 28:43, 1992 Miller MW, Fossum TW: Pericardia! disease. In Kirk RW, Bonagura JD (eds): Current Veterinary Therapy, vol XI. Philadelphia, WB Saunders, 1993, p. 725 Montgomery RD, Hankes GH: Ureterocolonic anastomosis in a dog with transitional cell carcinoma of the urinary bladder. JAm Vet Med Assoc 190:1427, 1987 Moore AS, Cardona A, Shapiro W, eta!: Cisplatin (cisdiamminedichloroplatinum) for treatment of transitional cell carcinoma of the urinary bladder or urethra. J Vet lntem Med 4:148, 1990 Moreland KJ: Ulcer disease of the upper gastrointestinal tract in small animals: Pathophysiology, diagnosis, and management. Compend Conlin Educ Pract Vet 10:1265, 1988 Moroff SD, Brown BA, Matthiesen DT, et al: Infiltrative urethral disease in female dogs: 41 cases (1980-1987). JAm Vet Med Assoc 199:247, 1991 Nelson AW: Lower respiratory system. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p . 777 Ogburn PN: Cardiovascular system. In Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders, 1993, p . 2106 Ogilvie GK, Haschek WM, Withrow SJ, et a!: Classification of primary lung tumors in dogs: 210 cases (1975-1985). JAm Vet Med Assoc 195:106, 1989 Patnaik AK, Hurvitz AI, Johnson GF: Canine gastrointestinal neoplasms. Vet Pathol 14:547, 1977 Patnaik AK, Liu SK, Hurvitz AI, eta!: Canine chemodectoma (extra-adrenal paragangliomas). A comparative study. J Small Anim Pract 16:785, 1975
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63. Pavletic MM: Surgical stapling devices in small animal surgery. Compend Contin Educ Pract Vet 12:1724, 1990 64. Perry RE, Weller RE, Dagle GE, et al: Transitional cell carcinoma of the bladder with skeletal metastasis in a dog. JAm Anim Hosp Assoc 25:547, 1989 65. Pope ER, Rochat MC: Hematopoetic system. Spleen. In Bojrab MJ (ed): Disease Mechanisms in Small Animal Surgery, ed 2. Philadelphia, Lea &'Febiger, 1993, p . 616 66. Pastorino NC: Hepatic tumors. In Withrow SJ, MacEwen EG (eds): Clinical Veterinary Oncology. Philadelphia, JB Lippincott, 1989, p. 196 67. Reed JR: Pericardia) diseases. In Fox PR (ed): Canine and Feline Cardiology. New York, Churchill Livingstone, 1988, p. 495 68. Remedios A, Bauer MS, McMurphy R, et al: Mediastinal cystic lymphoma in a dog. J Am Anim Hosp Assoc 26:161, 1990 69. Rush JE, Keene BW, Fox PR: Pericardia) disease in the cat. A retrospective evaluation of 66 cases. JAm Anim Hosp Assoc 26:39, 1990 70. Saik JE, Toll SL, Diters RW, et al: Canine and feline laryngeal neoplasia. A 10-year survey. JAm Anim Hosp Assoc 22:359, 1986 71. Schwarz PD, Egger EL, Klause SE: Modified "cup-patch" ileocystoplasty for urinary bladder reconstruction in a dog. JAm Vet Med Assoc 198:273, 1991 72. Schwarz PD, Greene RW, Patnaik AK: Urinary bladder tumors in the cat: A review of 27 cases. JAm Anim Hosp Assoc 21:237, 1985 73. Shapiro W, Kitchell BE, Fossum TW, et al: Cisplatin for treatment of transitional cell and squamous cell carcinomas in dogs. JAm Vet Med Assoc 193:1530, 1988 74. Stanton ME: Gastric ulceration and neoplasia. In Bojrab MJ, Smeak DD (eds): Disease mechanisms in small animal surgery, ed 2. Philadelphia, Lea & Febiger, 1993, p . 232 75. Stone EA, Walter MC, Goldschmidt MH, et al: Ureterocolonic anastomosis in clinically normal dogs. Am J Vet Res 49:1147, 1988 76. Stone EA, Withrow SJ, Page RL, et al: Ureterocolonic anastomosis in ten dogs with transitional cell carcinoma. Vet Surg 17:147, 1988 77. Thomas WP: Pericardia) disorders. In Ettinger SJ (ed): Textbook of Veterinary Internal Medicine, ed 3. Philadelphia, WB Saunders, 1989, p . 1132 78. Thomas WP, Sisson D, Bauer TG, et al: Detection of cardiac masses in dogs by twodimensional echocardiography. Vet Radiol 25:65, 1984 79. Walshaw R: The small intestine. In Gourley IM, Vasseur PB (eds): General Small Animal Surgery. Philadelphia, JB Lippincott, 1985, p . 343 80. Walter PA, Feeney DA, Johnston GR, et al: Ultrasonographic evaluation of renal parenchymal diseases in dogs: 32 cases (1981-1986). JAm Vet Med Assoc 191:999, 1987 81. Waters OJ, Sweet DC: Role of surgery in the management of dogs with pathologic conditions of the thorax. Part I. Compend Contin Educ Pract Vet 13:1545, 1991 82. Willard MD: Fluid accumulation disorders. In Willard MD (ed): Small Animal Clinical Diagnosis by Laboratory Methods. Philadelphia, WB Saunders, 1989, p. 229 83. Withrow SJ: Tumors of the respiratory system . In Withrow SJ, MacEwen EG (eds): Clinical Veterinary Oncology. Philadelphia, JB Lippincott, 1989, p . 215 84. Withrow SJ: Surgical oncology. In Withrow SJ, MacEwen EG (eds): Clinical Veterinary Oncology. Philadelphia, JB Lippincott, 1989, p. 58 85. Woolfson JJ, Dulish ML: Open abdominal drainage in the treatment of generalized peritonitis in 25 dogs and cats. Vet Surg 15:27, 1986
Address reprint requests to Jolle Kirpensteijn, DVM, MS Department of Clinical Sciences of Companion Animals University of Utrecht Yalelaan 8 3508 TD Utrecht The Netherlands
SURGICAL ONCOLOGY
ONCOLOGIC SURGICAL EMERGENCIES Jolle Kirpensteijn, DVM, MS, and C. Dick van Zuilen, DVM
Emergencies often occur because of an underlying oncologic problem and pose a challenge for the medical and surgical oncologist.31- 33 Many tumor-related emergencies require immediate surgical intervention but are complicated by the debilitated state of the patient or ethical concerns for the patient's ultimate prognosis. The necessity of immediate surgery is determined by the acute nature of the problem, the physical status of the patient, and the availability of alternative treatment. A decision is made in which the progression of the disease, general health status of the patient, and experience of the clinician are extremely important. These factors influence surgical morbidity and mortality, the extent of surgery, postoperative management, and overall prognosis. Thus every oncologic emergency requires a thorough evaluation and individual therapeutic approach. The surgeon often plays a central role in the diagnosis, treatment, and aftercare of the cancer patient in an emergency situation. The first step in managing the emergency is to evaluate the patient's pathophysiologic status and to eliminate immediate threats to the patient's life. The anamnesis should include previous oncologic diagnoses, procedures, and therapies. At the same time, a cursory physical examination will point out signs of life-threatening complications that should be dealt with immediately to stabilize the patient's physical functions. After stabilization, a thorough physical examination is performed and a diagnostic and therapeutic plan is formulated. Further diagnostic steps include general tests (complete blood cell count, biochemistry and clotting profiles, and urinalysis) and cancer specific tests (fine-needle aspiration, radiography, From the Department of Clinical Sciences of Companion Animals, University of Utrecht, Utrecht, Holland
VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE VOLUME 25 • NUMBER 1 • JANUARY 1995
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ultrasonography, computer tomography [CT], and magnetic resonance [MR] imaging scans). The timing, selection, and purpose of surgical therapy varies with the type of cancer and the site of involvement. Timing depends on whether the emergency involves (1) a patient with stable vital functions and a problem requiring surgical correction; (2) a patient with compromised vital functions and a delayed threat to life; or (3) a patient with an immediate threat to life requiring surgical correction.45 Immediate surgery is only necessary in life-threatening situations and should be accompanied by adequate supportive care. The benefits of surgical intervention in cancer patients must be weighed against the risks of surgery. Operative morbidity and mortality depend on the basic disease process, the surgical procedure, anesthesia, and the patient's general status and ability to withstand operative trauma. 34 In oncologic patients, the basic disease process and debilitated state of the patient are major determinants of operative morbidity and mortality. Surgery may alleviate clinical signs in an emergency situation, but mortality rates can be high (Fig. 1). The goal of surgery may be complete excision of the tumor for cure, palliation, cytoreduction, or simply histologic confirmation of the tumor type. Complete excision of the tumor is the hopeful goal of surgery. Palliative surgery must improve the patient's quality of life, and perhaps prolong it. The aim of cytoreduction is to decrease tumor bulk to improve the efficacy of adjunctive treatment. Cytoreduction without adjunctive therapy is of no benefit to the patient. 34• 84 Regardless of resection type, surgery should resolve the emergency situation. Postoperative management includes monitoring the return of normal physiologic functions, evaluation of wound healing, the use of adjunctive therapy, and periodic assessment for tumor recurrence and metastasis. Intensive supportive therapy is often necessary after emergency surgery and may include intravenous administration of fluids, blood, or plasma, antibiotic therapy, and nutritional support.35 Every emergency cancer patient should be evaluated individually and carefully, and the risks and benefits of therapy should be explained to the client. SPECIFIC ONCOLOGIC EMERGENCIES Pericardia! Effusions and Neoplastic Cardiac Tamponade Pathophysiology
Pericardia! effusion caused by neoplasia of the heart or pericardium may result in cardiac tamponade, a potentially life-threatening situation.4 Tamponade is the uncontrolled increase in intrapericardiac pressure that causes decreased cardiac filling and output.53 This results in signs of right heart failure because the thinner right ventricle is more susceptible to external pressure. The severity of tamponade depends on the rate of pericardia! fluid formation, the volume accumulated, and the ability of
Thorough physical examination GeneraJ diagnostic tests Cancer specific diagn . tests Minimal supportive care
IRisk vs Benefit!
/
crrVE CANCER THERAPYI AnaJgesics
Chemotherapy Radiation therapy , ....~----------------" Immunotherapy Other
Fluid support Anubiotic therapy Corticosteroids
Nutrition
Figure 1. Algorithm for decision making in oncologic surgical emergencies.
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the pericardium to stretch.67 The pericardium can contain large volumes, if the effusion develops gradually, but in acute cases small volumes cause
severe clinical signs.1o, 77 Neoplasia, primary or metastatic, were the most common cause of pericardia} effusion in a study of 42 dogs.5 Primary cardiac tumors are rare and include hemangiosarcoma/1· 40 heart base tumors,62 mesothelioma/1 and sarcoma.49 Tumors reported to metastasize to the heart or pericardium are hemangiosarcoma, lymphoma, melanoma, and mammary adenocarcinoma. 4• 69 Malignant pericardia} effusion is not common in cats and is most often caused by lymphoma.69 Clinical Presentation and Diagnosis
Clinical signs associated with acute pericardia} effusion and tamponade include lethargy, dyspnea, anorexia, collapse, abdominal distension, sudden death, exercise intolerance, and coughing. 5• 59 Most effusions develop gradually and cause signs of chronic cardiac compression, (i.e., weight loss, muffled heart sounds, jugular pulse, ascites, dyspnea, tachycardia, splenomegaly, and hepatomegaly). 77 Thoracic radiographs, electrocardiography, and ultrasonography can confirm the diagnosis.59 Pneumopericardiography can be used to detect intrapericardiac masses/0 alternatively, ultrasonography is often used to detect masses and to guide pericardiocentesis.53• 78 Pericardiocentesis under ultrasonographic and electrocardiographic guidance can be performed for both diagnostic and therapeutic purposes. An over-the-needle catheter is inserted in the right fourth to sixth intercostal space near the costochondral junction. The right side is preferred to prevent laceration of the coronary artery. After the pericardium is punctured, the catheter is advanced, the needle is removed, and all fluid is evacuated.4• 77 The pericardia} fluid should be submitted for biochemical and cytologic examination. Tumor cells are rarely found during cytologic examination of malignant effusions or, in the case of mesothelioma, are difficult to differentiate from reactive mesothelial cells.82 Surgical Therapy and Aftercare
Therapy of patients with pericardia! effusions is directed at quickly reducing intrapericardial pressure by centesis or surgical drainage. 53 Therapeutic pericardiocentesis is indicated in dogs with cardiac tamponade, but is often of short beneficial effect.Z5 Immediate surgical intervention is indicated in active intrapericardia} hemorrhage, if pericardia} distension cannot be relieved, or if clinical signs caused by intrapericardiac masses are severe. The main objective of surgery is to remove the tumor causing the effusion, but palliative pericardiectomy is indicated in selected cases. The surgical approach and procedure depends on tumor localization and tumor type and includes lateral thoracotomy or median sternotomy. Heart base tumors are slow growing and are often detected in a late stage of disease, so surgical resection is seldom possible. Pericardiectomy,
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as a palliative procedure, is a good alternative to euthanasia or repeated pericardiocentesis for these dogs and has allowed comfortable survival up to 4 years. 77 Hemangiosarcoma is commonly located on the right auricle and can be excised surgically if small. The use of a cardiovascular stapling device allows rapid and safe excision63; however, this therapy is often palliative because of concurrent metastases to the pericardium, lungs, or other distant sites. 4• 5• 40• 77 The prognosis for dogs with cardiac hemangiosarcoma is poor and comparable to involvement of other sites.21 The median survival of 15 dogs treated with vincristine, doxorubicin, and cyclophosphamide for hemangiosarcoma was 172 days38 compared with 60 days in dogs not treated with chemotherapy.40• 42 Respiratory Emergencies
Pathophysiology
Respiratory oncologic emergencies are caused by acute respiratory distress associated with tumors near or in the respiratory tract. The four most common respiratory emergencies are airway obstruction, hemorrhage, malignant pleural effusion, and superior vena cava syndrome.31 Tumor-induced airway obstruction can be caused by intraluminal masses or extraluminal compression. Intraluminal tumors can be located in the larynx, trachea, or main stem bronchi. Various types of tumors have been reported, but the incidence is relatively low. 3• 29• 37• 7°Compressive lesions are often associatedwith the thyroid (adenocarcinoma), esophagus (squamous cell carcinoma), lymph nodes (submandibular, retropharyngeal, mediastinal, or hilar), thymus (thymoma, malignant lymphoma), and other mediastinal structures.68 Primary or metastatic lung tumors are reported to cause peracute pneumothorax, hemoptysis, and hemothorax, although the incidence of these complications is low. Pleural effusion is caused by mediastinal, pleural, or pulmonary tumors that obstruct lymphatic drainage or cause inflammation, hypoalbuminemia, or hemorrhage. Malignant or tumor-induced pleural effusion can be treated effectively by closed-tube thoracostomy and rarely needs immediate surgical intervention. Superior vena cava syndrome (SVCS) is a clinical expression for obstruction of venous return from head, neck, and forelimbs caused by a process compressing the cranial vena cava. SVCS has been described in the dog but is extremely rare. 31 Theoretically, SVCS can be caused by extraluminal compression or by tumor ingrowth into the vena cava. Clinical Presentation and Diagnosis
The most common signs of tumor-induced airway obstruction are progressive dyspnea, stridor, coughing, and exercise intolerance. Most of these signs are chronic, but peracute respiratory dyspnea can develop because of hyperthermia, edema and hemorrhage related to the tumor, accumulation of secretions and debris, or laryngeal spasm. Useful diag-
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nostic procedures are laryngeal and tracheal palpation, endoscopy, radiology, ultrasonography, and cytological examination of fine-needle aspiration.29 Early diagnosis can be obtained by endoscopic-guided biopsy. Clinical signs caused by pulmonary neoplasia include coughing, dyspnea, lethargy, weight loss, tachypnea, hemoptysis, and exercise intolerance.29· 60 Thoracic radiographs and cytologic examination of percutaneous fine-needle aspirates are the most valuable diagnostic methods. Additional diagnostic testing (transtracheal lavage, ultrasonography, or bronchoscopy) are not necessary in an emergency situation for solitary lung lesions because in most cases surgical excision is the therapy of choice.83 In contrast, additional diagnostic testing can be very useful for metastatic disease or pleural effusions. Malignant pleural effusion may cause peracute clinical signs including tachypnea, dyspnea, decreased exercise intolerance, abdominal breathing, and cyanosis.28 Decreased respiratory and cardiac sounds ventrally, in combination with dullness on percussion, are pathognomonic physical findings. Definite diagnosis is made by thoracic radiography and thoracocentesis. 28· 81 Progressive dyspnea and swelling of the face, neck, and forelimbs caused by edema, are the most common signs of SVCS. The onset is often insidious, but peracute dyspnea can be seen as the disease progresses.31 Radiographs, ultrasonography, and CT scans of the cranial thorax often allow the tumor to be localized. Diagnosis of tumor type may be obtained using fine-needle aspiration or cutting biopsy needle. Surgical Therapy and Aftercare
Initial therapy for tumor-induced respiratory emergencies is identical to that for other respiratory distress syndromes and may include supplemental oxygen therapy, tracheostomy, and thoracostomy tube placement. Tumor-induced upper airway obstruction is treated by tracheostomy or tumor removal. Emergency tracheostomy is indicated for life-threatening upper respiratory obstructions, in which the condition of the patient does not allow extensive surgery, or for immediate palliation. Several methods of creating a temporary tracheostomy are described, and the procedure can often be performed on an emergency basis with minimal anesthetic restraint. 58 Complete tumor excision is the therapy of choice in benign tumors (oncocytoma, leiomyoma, and polyps) obstructing the respiratory tract and results in an excellent prognosis. If obstruction is caused by a laryngeal tumor, partial or total laryngectomy can be performed. Some pedunculated tumors can be removed via the mouth, but partial laryngectomy via ventral laryngotomy incision is necessary for larger neoplasms. 29· 83 Extensive malignant tumors of the larynx may require total laryngectomy and permanent tracheostomy. 19 To remove tracheal tumors an end-to-end tracheal anastomosis is often necessary. Four rings (12%) of the trachea can be resected easily, although in a few cases successful resection of 25% to 50% of the trachea has been reported. 29· 58 The incidence of tracheal stenosis and dehiscence increases after extensive tracheal resection because of increased longitudinal ten-
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sion.58 Chemotherapy and radiation therapy have been described.29, 70 Of the two, radiation seems to be most successful, especially for malignant lymphoma of the larynx and trachea. 29 Emergency surgical intervention is seldom necessary in dogs with pulmonary neoplasms. Pneumothorax and pleural effusions are commonly treated successfully with a thoracostomy tube. 20 Two indications for immediate surgical exploration are active hemorrhage, and a nonproductive thoracostomy tube in the presence of serious pneumothorax or pleural effusion. Exploratory thoracotomy is performed via an intercostal incision or median sternotomy. Isolated primary pulmonary masses are best treated by removal of the affected lung lobe through an intercostal thoracotomy. The use of thoracoabdominal staplers has simplified the procedure and decreased morbidity. 60 Regional lymph nodes undergo a biopsy procedure if enlarged. The prognosis is most favorable in dogs with small tumors and no lymph node involvement. More than 50% of these patients survive at least 1 year after surgery. 83 There is no proven effective therapy for canine or feline SVCS. Surgical excision of discrete mediastinal, pulmonary, or cardiac masses may eliminate clinical signs. Radiation therapy to reduce the tumor mass seems to be the therapy of choice in humans and may be beneficial in animals. 31 Hemorrhagic Abdominal Emergencies Pathophysiology
Hemorrhagic abdominal emergencies develop secondary to direct extension and ulceration of various malignant tumor types into the peritoneal cavity, or to rupture of an organ enlarged from tumor invasion. Abdominal hemorrhage is most frequently associated with splenic or hepatic tumors. The most common canine splenic tumor is hemangiosarcoma. It usually affects older animals and metastasizes in more than 50% of cases to other organs including lungs, heart, liver, kidney, omentum, and peritoneum.42' 48 Mast cell tumor and malignant lymphoma occur most frequently in the spleen of cats.65 Any enlarged spleen may rupture, resulting in internal blood loss and hypovolemic shock. 65 Primary hepatic tumors occur in older dogs and cats but are rare. Hepatocellular carcinoma is most common, and it frequently metastasizes to regional lymph nodes, lung, and peritoneum.46, 66 More common than primary hepatic tumors, metastatic tumors include malignant lymphoma, pancreatic adenocarcinoma, and hemangiosarcoma.16' 66 Massive hemorrhage can occur from any hepatic tumor and may require emergency laparotomy. 8 Clinical Presentation and Diagnosis
Abdominal hemorrhage results in abdominal enlargement, pale mucous membranes, lethargy, abdominal pain, tachycardia, tachypnea, and
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vomiting. Clinical signs vary with the severity of bleeding. In patients with exsanguinating hemorrhage, clinical signs of hypovolemic shock predominate. Once a diagnosis of abdominal effusion is made, little additional information is obtained by radiographic examination. The presence of fluid decreases the value of radiography but enhances the use of ultrasonography. Radiography after removal of fluid by abdominal paracentesis may improve visualization of intra-abdominal structures and assist in diagnosis. 24 Fluid obtained should be examined cytologically. Neoplastic cells may be identified in aspirated fluid, but neoplastic disease should not be excluded on basis of negative findings. 66 To differentiate hemorrhage from serosanguinous exudate, the packed cell volume and white blood cell counts are compared with those of peripheral blood.82 The packed cell volume of serosanguinous exudates rarely exceeds 5%.18 An increase in packed cell volume in sequential samples may indicate continuing intra-abdominal bleeding. Alternatively, intra-abdominal masses can be diagnosed by ultrasonography and guided fine-needle aspiration. Nondiagnostic samples are relatively common because of sampling errors and because little material is obtained from some tumor types. Definite diagnosis may require histologic examination of a surgical biopsy specimen. In patients with abdominal hemorrhage, clotting ability should be investigated before surgery because disturbances can be caused by the tumor. In up to 50% of dogs with splenic hemangiosarcoma, there is diffuse intravascular coagulation.38 Surgical Therapy and Aftercare
The clinical status of the patient dictates the type of treatment. An initial period of medical stabilization before surgical intervention may improve prognosis. Supportive therapy consists of intravenous fluid, hypertonic saline, or colloid therapy, blood transfusions, and pressure wraps. Blood transfusions are often necessary in dogs with exsanguinating abdominal hemorrhage. Autotransfusion, rather than heterologous blood transfusion, is contraindicated in tumor-induced abdominal hemorrhage, because it can spread tumor cells. Increased intra-abdominal pressure by application of an abdominal pressure wrap may help control hemorrhage. Compressive abdominal and pelvic bandages are the practical alternative for seldom available antishock garments. 18 Emergency laparotomy is indicated if, despite fluid and blood replacement, the animal deteriorates. 18 The abdomen should be explored thoroughly to locate the source of bleeding and to search for signs of metastases. Total splenectomy often is life saving in hemorrhaging splenic malignancies, but a cure is rarely obtained. The prognosis for dogs with a ruptured hemangiosarcoma after splenectomy is poor, because of the tumor's aggressive metastatic behavior. An average survival time of 2 months without and 6 months with adjuvant chemotherapy has been reported. 38, 42 In contrast to malignant tumors, benign splenic tumors have
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an excellent prognosis after surgical removal. The use of ligating-dividing staplers (LDS) allow expedient and safe surgical removal of hemorrhaging splenic neoplasms. 63 Surgical excision by partial or total hepatic lobectomy is the treatment of choice for bleeding hepatic tumors located in a single lobe?, 46 The prognosis for benign hepatic tumors is good, survival times of more than 2 years have been reported. 66 Malignant hepatic tumors carry a poorer prognosis,66 although lobectomy in dogs with hepatocellular adenocarcinoma resulted in a mean survival of 377 days.46
Urogenital Oncologic Emergencies Pathophysiology
Urogenital oncologic emergencies are often related to obstruction of the ureter, bladder neck, or urethra, or to hemorrhage from the tumor. Obstructive lesions can be located extramural (intra-abdominal, retroperitoneal, or intrapelvic), intramural (renal, ureteral, bladder, or urethral wall), or intraluminal. Extramural obstruction is caused by tumors in many anatomical locations including prostate (adenocarcinoma), rectum or colon (adenocarcinoma), vagina (leiomyoma or fibroma), and regional lymph node (lymphoma or metastasis)Y Intramural and intraluminal obstructions are most often caused by transitional cell carcinomas,64, 76 renal tumors,43 and benign proliferations.57 Serious and life-threatening abdominal hemorrhage and hematuria is often caused by renal tumors from direct extension of the tumor into the peritoneal or renal pelvic space. Renal tumors are usually malignant in the dog and cat, metastasize in up to 50% of cases, and most commonly affect older animals. 43 Primary renal tumors include tubular cell carcinoma, transitional cell carcinoma, fibrosarcoma, hemangiosarcoma, and nephroblastoma in the dog and lymphoma, renal carcinoma, sarcoma, and nephroblastoma in the cat. 2' 12' 36 Ureteral tumors are rare but can cause hydronephrosis. 27' 39 Bladder and urethral tumors are more common than renal or ureteral tumors and are most prevalent in female dogs and male cats. Except for rhabdomyosarcoma, bladder tumors affect older animals, and the most common tumor type in dogs and cats is transitional cell carcinoma. 12, 64, 72 Transitional cell carcinomas are highly invasive tumors that grow slowly often in the trigone area and bladder neck. Emergencies associated with bladder and urethral tumors are usually caused by obstruction of the urethra or ureter. These tumors eventually metastasize in 80% of dogs. Common sites include the lung, lumbar lymph nodes, kidney, prostate, and liver. Benign diseases must also be considered in the differential diagnosis. Chronic and acute renal failure, urinary tract infections, urolithiasis, ureteral strictures, cyclophosphamide-induced cystitis, and neurologic abnormalities could cause similar signs.
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Clinical Presentation and Diagnosis
Clinical signs depend on the location and size of the tumor. Renal and ureteral tumors are associated with hematuria, renal enlargement, abdominal pain, anorexia, depression, and weight loss.36' 43 Physical examination may show a large, painful abdominal mass, and the diagnosis is confirmed by abdominal radiography,43 ultrasonography,80 contrast studies (intravenous pyelogram)/ renal scintigraphy, CT, or MR imaging scans. Routine serum chemistry and urinalysis allows evaluation of kidney function. Ultrasonographic guided fine-needle aspiration of the tumor facilitates early diagnosis. Dysuria, hematuria, polyuria, pollakiuria, or anuria are observed with lower urinary tract tumors. 57 Neoplasms associated with the bladder and urethra may be palpated by abdominal and rectal examination. Other useful diagnostic procedures include abdominal radiography, ultrasonography, and contrast studies (intravenous pyelogram, double contrast cystogram, retrograde urethrogram). Malignant cells are seldom found in the urine sediment but may be obtained by catheter biopsy or percutaneous fine-needle aspiration of prostate and urethraY Direct cystoscopic visualization of the tumor in the bladder or urethra is often possible in female dogs, and the diagnosis is confirmed by cystoscopic biopsy. Surgical Therapy and Aftercare
Surgical therapy depends on the site of obstruction. Unilateral nephrectomy and ureterectomy are indicated for renal tumors if the opposite kidney is functional, and if metastases are not present.36• 43 Mean survival time after nephrectomy for dogs with renal tubular cell carcinoma was 7 months and for dogs with transitional cell carcinoma it was 11 months. 43 Surgical excision is the therapy of choice for cystic and urethral transitional cell carcinomas but is often impossible because of tumor location. Partial cystectomy may be successful in tumors not affecting the trigone. The tumor must be excised with a wide margin of normal tissue and the remainder of the bladder wall is inspected. Even after excision of more than 75% of the urinary bladder, function can eventually return to normal or near normal. 57 A modified "cup-patch" cystoplasty can be performed in resections of more than 80% of the bladder.71 When the trigone is involved, reimplantation of the ureters in the remaining bladder may be necessary. Total cystectomy has been combined with urinary diversion, but postoperative complications have made these salvage procedures less beneficial.3°· 50• 51• 75 Ureterocolonic anastomosis seems to be most successful of the urinary diversion techniques.54• 76 In general, survival times after surgical excision of bladder and urethral transitional cell carcinoma are limited because of recurrence or metastasis. Temporary relief can also be obtained using an indwelling urinary or prepubic cystostomy catheter.22• 23 The placement of cystostomy catheters is relatively simple and is associated with few complications and easy home management. This technique can be used in combination with adjuvant therapies or as palliation. A permanent cystostomy catheter
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eliminates the need for immediate euthanasia in dogs with advanced bladder and urethral cancer. Adjuvant radiation or chemotherapy may be indicated but has been associated with high rate of complications and tumor recurrence. There are fewer complications, and survival rates may be better in dogs treated with external-beam megavoltage radiation therapy in combination with a slowrelease biodegradable polymer containing cisplatin implanted at a distant site (SJ Withrow, personal communication 1993). Results of systemic or intravesicular administration of chemotherapy for transitional cell carcinoma have been variableY· 73 Partial response or stable disease was seen after intravenous cisplatin therapy in 9 of 12 dogs. 55 Also, the use of the nonsteroidal anti-inflammatory drug piroxicam has been beneficial in obstructive canine transitional cell carcinoma, at least for palliation.44 Complications after oncologic bladder or urethral surgery include incontinence, postoperative diuresis, pollakiuria (small bladder syndrome), and infection. Incontinence is treated with parasympathomimetic drugs (e.g., bethanechol chloride) for partially denervated bladders, adrenergic agonists (e.g., ephedrine) for low-pressure incontinence, anticholinergics (e.g., probanthine) for reflex neurogenic bladders, and sympatholytic drugs (e.g., phenoxybenzamine) for urethral spasms. Postobstructive diuresis should be compensated appropriately with intravenous fluid administration. Infection should be treated with antibiotics based on culture and sensitivity results. Gastroenterologic Emergencies
Pathophysiology
Acute gastrointestinal emergencies are caused by gastrointestinal perforation, obstruction, or intraluminal hemorrhage. Perforation occurs as a sequelae to ulceration of gastric or intestinal tumors, poor wound healing after enterotomy, chemotherapy for lymphoma and m ast cell tumors, or mast cell tumor-induced ulceration. 9 Gastrointestinal perforation quickly induces fulminant peritonitis resulting in fluid, electrolyte and protein losses, acid-base imbalances, hypoglycemia, diffuse intravascular coagulopathy, circulatory collapse, and septic shock. Gastrointestinal obstruction is caused by tumor encroachment or by adhesions from intra-abdominal masses. 31 Obstruction causes fluid and gas accumulation proximal to the site of obstruction and an increase in intraluminal pressure. Continued distension results in venous congestion, mural edema, decreased absorption, and increased secretion. Fluid and electrolytes are lost and significant vascular compromise may result in devitalization of the intestinal wall. At this point, the mucosal barrier is impaired and bacterial translocation results in progressive septic and hemodynamic shock. Intraluminal hemorrhage is commonly seen after ulceration of such tumors as mast cell tumors, gastrinomas, gastric and intestinal carcinomas, lymphoma, and metastatic tumors. 56 Gastric and intestinal tumors are relatively uncommon in dogs and
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cats and include adenocarcinoma,B· 47 leiomyoma/4• 52 leiomyosarcoma/4 malignant lymphoma/5• 16 mast cell tumor,9 polyps/4 and fibrosarcoma.U· 61 • 79 Mainly older animals are affected and adenocarcinoma is most common in dogs and lymphoma in cats.6 Relatively more nonlymphoid gastrointestinal tumors are reported in Siamese cats, Boxers, Collies, Staffordshire Bull terriers, and German shepherds compared with other breeds.6• 47• 81 More than two thirds of gastrointestinal tumors are malignant, and early metastasis to regional lymph nodes, liver, and lung in combination with ulceration are observed frequently.1 5• 47 Clinical Presentation and Diagnosis
Clinical signs associated with gastrointestinal tumors are nonspecific and include vomiting, diarrhea or constipation, anorexia, abdominal pain, ascites, and distension. 6• 11• 15• 47 Partial or total obstruction of the gastrointestinal tract is relatively common, and the mostcommon signs are protracted vomiting, abdominal pain, and abdominal distension. 26 With perforation, signs quickly progress to severe depression, dehydration, and signs of cardiovascular and septic shock. Intestinal bleeding is associated with signs of anemia, weight loss, hematemesis, hematochezia, diarrhea, and melena. 14 . Ascites, dilated intestines, solitary masses, and excessive borborygmi can be detected during physical examination. Radiography and ultrasonography allow further examination and localization of abdominal masses, ileus, or free air. 26 Diagnosis can be obtained using ultrasoundguided fine-needle or cutting biopsy of the tumor. Barium or iodine (if perforation is suspected) contrast studies may locate the tumor if plain radiography does not. Endoscopy is useful 'in locating and obtaining biopsy specimens from gastric, duodenal, colonic, and rectal tumors, but is seldom used in an emergency situation. Gastrointestinal perforation is accurately diagnosed by paracentesis or peritoneal lavage and immediate exploratory surgery is necessary if intracellular and extracellular bacteria, or foreign material are found on cytological examination. Rarely, diagnostic" peritoneal lavage may fail to demonstrate bacteria if the spillage caused by the perforation is localized. Repeat peritoneal lavage, radiography with water soluble contrast material, or exploratory surgery is indicated in these cases. Surgical Therapy and Aftercare
Severe active bleeding into the digestive tract, partial or complete obstruction, or gastrointestinal perforation necessitate emergency explorative laparotomy.8 Preoperative supportive care is directed to correcting fluid, electrolyte, and acid-base imbalances, and to treating septicemia and endotoxic shock.79 Supportive therapy may consist of blood transfusion, intravenous fluid or colloid administration, and antibiotic administration covering gram-negative and anaerobic bacteria (e.g., cephalosporins or aminoglycosides in combination with metronidazole). After routine celiot-
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omy, the abdomen is explored and the extent of gastrointestinal involvement is assessed. Regional lymph nodes and liver are inspected for possible metastasis. At this point, biopsy specimens of tumor and regional lymph nodes can be obtained and submitted for cytological and histological examination. Histologic examination of frozen sections allows immediate diagnosis in most cases. For gastric tumors, complete resection is the therapy of choice.U Because of frequent involvement of antrum and pylorus (50% of cases), partial gastrectomy as a Billroth I or II procedure is often necessary to obtain wide surgical margins. 15 Enlarged local lymph nodes undergo a biopsy procedure or are excised en-bloc. Partial gastrectomy is contraindicated in dogs with gastrointestinal lymphoma because of the diffuse nature of the disease, effective chemotherapy options, and associated complications with wound healing. Solitary lymphomatous lesions seem to respond better to surgery and adjunctive chemotherapy. 15, 16 Intestinal neoplasms are usually treated by wide surgical resection and anastomosis. A simple end-to-end anastomosis often is sufficient but more complex intestinal reconstruction is sometimes necessary. Tumors that have already metastasized may be excised effectively for palliation. Resection of regional lymph nodes and other sites of metastasis may decrease the total tumor burden enhancing the effect of adjuvant therapy. The use of serosal or omental patching at the surgery site is indicated for extensive resections or in patients with suspected impaired wound healing.17 The need for gastric or intestinal feeding tubes should be assessed before closure. Surgical placement of gastrostomy and jejunostomy feeding tubes is relatively easy and is described previously. 1 The benefits of improved nutritional status in cachectic cancer patients far outweigh the management disadvantages of surgically placed feeding tubes. General peritonitis after intestinal perforation is treated aggressively. Intraoperative cultures are obtained, and the abdominal cavity is lavaged with copious amounts of warm 0.9% saline solution. Open abdominal drainage is used in severe cases of peritonitis.85 For open abdominal drainage, the linea alba is closed with a loose simple continuous polypropylene suture pattern and the subcutis and skin are left open. A sterile bandage is placed over the wound and is changed as often as required. Periodic surgical lavage under strict aseptic conditions may be of benefit. The use of sterilized commercial diapers decreases the need of frequent bandage changes caused by fluid penetrating the outer bandage. Postoperative care includes continuing fluid and electrolyte therapy. Initially small quantities of water are offered, and if vomiting does not occur, small quantities of soft food can be fed. Anorectic animals may be force fed by nasogastric, endoscopically or surgically placed gastrostomy, or jejunostomy tubes. 1 After intestinal anastomosis, breakdown of the suture line most commonly occurs during the second and fourth day postoperatively and signs of physical deterioration during that time should be investigated.79 Nonperforating ulceration of the gastrointestinal tract directly or indirectly caused by tumors can be treated medically
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using antacids (e.g., aluminum hydroxide), histamine2 antagonists (e.g., cimetidine), coating agents (e.g., sucralfate), and proton pump inhibitors (e.g., omeprazole).56· 74 Malignant tumors of the gastrointestinal tract may benefit from adjunct chemotherapy because of their aggressive metastatic behavior.79 The effect of chemotherapy for canine gastric adenocarcinoma and canine and feline intestinal adenocarcinoma have been discouraging.l5· 81 Complete remission with survival times of 12 and 17 months were seen in two dogs with metastatic intestinal adenocarcinoma treated with surgical resection of the primary tumor and cisplatin and 5-fluorouracil chemotherapy (SO Gilson, personal communication 1994). Gastrointestinal malignant lymphoma is less responsive to chemotherapy than the multicentric type. Also, complications associated with intestinal perforation after chemotherapy should be taken into consideration. Because their aggressive metastatic behavior (up to 75%), the prognosis for gastrointestinal malignancies is guarded. 15· 26· 79 The prognosis is poor if the n.tmor is extensive, if metastasis is present, or when the tumor erodes through the serosal surface. The mean survival time of 12 dogs with malignant nonlymphoid gastrointestinal tumors that survived the first 2 weeks after surgery was 114 days without adjunctive chemotherapy.6 Mean survival of cats with resected adenocarcinoma was 15 months. 47 CONCLUSION
Surgical emergencies are relatively common in small animal cancer patients and pose a clinical and ethical challenge for the oncologist. The most common emergencies include pericardia! effusion and tamponade, respiratory distress, abdominal hemorrhage, and urogenital, or gastrointestinal obstruction or perforation. After emergency stabilization, the question of whether surgical intervention is proper and necessary needs to be answered. Immediate surgery is only indicated in life-threatening situations in which the risks versus the benefits of surgery have been weighed and should be accompanied by adequate preoperative and postoperative supportive care. ACKNOWLEDGMENT The authors thank Professor doctor F.J. van Sluijs for editing the manuscript.
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Address reprint requests to Jolle Kirpensteijn, DVM, MS Department of Clinical Sciences of Companion Animals University of Utrecht Yalelaan 8 3508 TD Utrecht The Netherlands