- Email: [email protected]
Diverticulitis
GASTROINTESTINAL EMERGENCIES
0025-7125/93 $0.00
+ .20
DIVERTICULITIS COL Stephen R. Freeman, MC, MD, and LTC Peter R. McNally, MC, DO
Diverticulosis coli is one of the most common diseases seen in western civilization. In America, one third of the population will have diverticulosis coli by age 50 and approximately two thirds by the age of 80. 34,43 Fortunately, diverticulosis remains asymptomatic in the majority, with only 10% to 20% of patients suffering complications of diverticulitis or diverticular hemorrhage during their lifetime. 4,47 The precise pathogenesis of diverticular disease is unknown; however, aging,23 elevation of colonic intraluminal pressure,42 and decreased dietary fiber appear related. 33 In western societies, the prevalence of diverticular disease abruptly increased 30 years after the introduction of grain milling factories, which greatly decreased the amount of dietary grain fiber. 41 Other dietary factors such as increased consumption of beef, beef fat, and salt are also suggested as causative factors.32 Decreased luminal fiber lowers stool volume and requires more colonic segmentation to propel the material aborally.40 Segmentation generates greater intraluminal pressures and may predispose to formation of diverticula. The colonic wall is inherently weakest where nutrient arteries penetrate the muscularis propria and diverticula typically arise there. Among European decendents, colonic diverticula are most commonly found in the sigmoid colon (over 85%)? The smaller luminal diameter of the sigmoid and resultant increase in wall tension is thought to be responsible for this,61,63 Defecation using standard western society toilets generates much greater intra colonic pressures than seen in the third world where knee chest position of defecation and pit latrines are common. This has led some to suggest the unappealing notion that the use of toilets are in part responsible for the geographic disparity in the prevalence of diverticuloSiS,51
From the Department of Medicine, Gastroenterology Service, Fitzsimons Army Medical Center, Aurora, Colorado MEDICAL CLINICS OF NORTH AMERICA VOLUME 77 • NUMBER 5 • SEPTEMBER 1993
1149
1150
FREEMAN & McNALLY
Permeation of western culture and diet in parts of the Far East is thought to be responsible for the increase in diverticulosis seen. 54 The 20% prevalence of diverticulosis seen in patients undergoing routine barium enema examination in Singapore parallels that seen in many western countries.lO Genetic or other environmental factors must also be important in the evolution of diverticular disease because diverticula are site specific to the right colon among Asians, whereas diverticula have a proclivity for the sigmoid and left colon and occur a decade later among occidentals.9, 44, 58 Complications of diverticulosis include hemorrhage and diverticulitis. It is interesting that these complications are mutually exclusive. Patients with diverticular hemorrhage do not generally develop diverticulitis (perforation, stricture, fistulae) and vice versa. 48 The diverticular complication of gastrointestinal hemorrhage are reviewed elsewhere in this issue. CLINICAL PRESENTATION
The signs and symptoms of diverticulitis vary widely, but abrupt onset of abdominal pain and alteration in bowel pattern are present in nearly all. Mild early acute diverticulitis, peridiverticulitis, is characterized as circumscribed, abdominal pain and tenderness. Usually the pain is unremitting and localized to the left lower quadrant; however, inflammation can occur anywhere that diverticula are foufld. Hence, inflamed diverticula of the transverse colon may simulate ulcer pain and diverticulitis of the cecum and redundant sigmoid may appear clinically identical to appendicitis. The pain of diverticulitis is often accompanied by generalized malaise and elevation in peripheral white blood count. The severity of pain and the persistence of symptoms, as well as signs of inflammation (fever, white count, and sedimentation rate) help to distinguish colonic spasm from diverticulitis. Still, it is often difficult to distinguish patients with mild peridiverticulitis from those with irritable bowel syndrome with coincidently discovered diverticula. Importantly, a patient young of age «40 years) should not preclude the consideration of diverticulitis from the differential diagnosis of abdominal pain. 60 Episodes of diverticulitis appear to be more virulent in the young and very elderly, with surgical intervention often necessary?1,39,50 If peridiverticulitis progresses, then localized abscess and phlegmonous reaction may occur. Pain and tenderness continue and a palpable mass may become evident. Plain films of the abdomen may show signs of obstruction, mass effect, or ileus. Systemic signs of infection may become pronounced, such as fever and elevated white count. Unlike occidentals, right sided diverticulosis is typical among Asians (>75%) and acute diverticulitis should be considered in those presenting with right-sided abdominal pain and fever. 29 Native Africans were once thought to be immune to this disorder; however, adoption of western culture and diet have been paralleled by an increase in the prevalence of diverticulitis in the sub-Saharan Desert?' 25, 38
DIVERTICULITIS
1151
It must be emphasized that the abdominal examination in diverticulitis may be deceptively unremarkable in the elderly and in persons on corticosteroids. s, 12 Greater reliance on computerized tomography to guide the management of these patients is reasonable because delay in the diagnosis of free perforation or abscess may increase operative mortality to approximately 50%. Palpation of an abdominal mass in any patient with clinically suspected diverticulitis is an indication for computerized tomography. Other signs and symptoms of diverticulitis are highly variable and nonspecific. In the past, obstipation was emphasized as a symptom of diverticulitis, but many patients actually have diarrhea. Obstipation may also be due to other nondiverticular disease such as obstructing colon carcinoma. Frank rectal bleeding is not seen with diverticulitis and should be ascribed to other causes, for example, hemorrhoids, polyps, tumors, arteriovenous malformations (AVM's), or arterial bleeding of painless diverticulosis. Cautious sigmoidoscopic examination may be very helpful in this circumstance. A practical approach to the patient with suspected acute diverticulitis is presented in Table 1. COMPLICATIONS OF DIVERTICULITIS Fistula
Chronic diverticulitis is associated with an inflammatory reaction that can adhease intra-abdominal organs to the colon. With repeated attacks of diverticulitis, a fistulous tract can form. Fistulous communications between bowel, urinary bladder, integument, pelvic floor, and vagina have been reported. Colon to urinary bladder (colovesicular) fistula is the most common form of diverticular fistula. 19 This complication is seen almost exclusively in men. Pneumaturia is an uncommon, but a pathognomonic feature of colovesicular fistula. More commonly, the diagnosis should be suspected in persons with recurrent urinary tract infections, especially if temporally associated with diverticulitis or characterized by multiple organisms. The fistulous communications can be very small. Reflux of contrast into the urinary bladder during contrast enema confirms the diagnosis, but is not often positive. Cystoscopy may show focal cystitis, but the fistulous communication may be obscured by chronic inflammation. Surgical correction is usually indicated for all colovesicular fistulae. Technical aspects of this procedure are described under the treatment of diverticular complications. Complicated diverticular disease is the most common cause of colovaginal fistulas 18 and they are seen almost exclusively in women with prior hysterectomies (80%).64 Other causes include pelvic irradiation, regional ileitis, gynecologic surgery, and pelvic abscess of any source. Clinically, colovaginal fistula may present variably from persistent, scant vaginal discharge to severe vaginitis. Flatus vaginalis and feculent dis-
1152
FREEMAN & McNALLY
Table 1. A PRACTICAL APPROACH TO THE EVALUATION AND DIAGNOSIS OF ACUTE DIVERTICULITIS Clinical history and physical examination Usually over 60 years of age LLQ localized tenderness and unremitting abdominal pain Fever Leukocytosis DDx Elderly Ischemia Carcinoma Volvulus Obstruction Penetrating ulcer Nephrolithiasis/urosepsis
Middle Aged and Young Appendicitis Salpingitis Inflammatory bowel Penetrating ulcer Urosepsis
Qualifiers Extremes of age (more virulent), oriental ancestry (right sided symptoms), corticosteroids, immunosuppressives, and chronic renal failure (abdominal examination insensitive). Evaluations Plain X-rays Good initial first step; may show ileus, obstruction, mass effect, ischemia, perforation. Contrast Enema For mild-to-moderate cases of diverticulitis when the diagnosis is in doubt water soluble contrast examination is safe and helpful, otherwise delay the examination for 6 to 8 weeks. Endoscopy Acute diverticulitis is a relative contraindication to endoscopy-must exclude perforation first. Examination only when the diagnosis is in doubt (rectal bleeding, anemia) to exclude the possibility of ischemic bowel, Crohn's disease, carcinoma. CT scan Very helpful in staging the degree of complications and evaluating for other diseases. Should be considered in all cases of diverticulitis with a palpable mass or clinical toxicity, failure of medical therapy, orthopedic complications, and corticosteroid use. The test of choice to evaluate acute diverticulitis in most centers. Ultrasound Can be a safe and helpful non invasive test to evaluate acute diverticulitis. Examinations suboptimal due to intestinal gas in 15%, very institution dependent.
charge are pathognomonic but less commonly seen. Usually symptoms of colovaginal fistula become manifest after an attack of diverticulitis. If symptoms of a vaginal fistula occur during an attack of acute diverticulitis, computerized tomography can be safely performed and can identify the fistula in up to 20% of cases,z4 The size of the fistula can be small and difficult to identify. Conventional methods used to identify the fistulous tract include barium enema and examination for dark vaginal discharge after oral charcoal. Adachi and Gold2 have reported the utility of contrast vaginography to identify occult fistulous communications. The technique requires insertion of a 30 mL balloon into the vagina. The balloon is filled and then contrast infused while lateral, oblique, and supine radiographs are taken to identify the fistulous connection. Simultaneous fiberoptic vaginoscopy and colonoscopy has also been recently shown to be a helpful technique in the identification of obscure colovaginal fistulae. 3 Regardless of the size of the fistula or the severity of symptoms, the fistula will persist until surgically corrected. Operations for complicated diverticulitis include resection of the diseased bowel with primary re-
DIVERTICULITIS
1153
anastomosis or a staged procedure as outlined in this article under surgical management of complicated diverticulitis. Obstruction
Muscular wall thickening, myocosis coli, is commonly seen in sigmoid diverticulosis. 45 With repeated episodes of subclinical diverticulitis, the colon becomes fixed, fibrotic, and stenosed. Colonic obstruction is most predisposed to the sigmoid where angulation is greatest. It is essential to exclude other causes of colonic stricture, such as carcinoma, Crohn's disease, and ischemia. Clues to the cause of colonic stricture by contrast radiography are cited in Table 2. If the stricture cannot, however, be definitively cleared by endoscopy or if the patient is symptomatic, then surgical resection is indicated. Abscess
Failure of any patient with acute diverticulitis to respond to medical therapy within 24 to 48 hours or palpation of an abdominal mass should always raise the suspicion of an intra-abdominal abscess. Abdominal computerized tomography or ultrasonography are excellent methods of evaluation for this complication. If a contained abscess cavity is identified, percutaneous drainage may be used to evacuate the cavity and augment medical therapy (Fig. 1). Successful utilization of this technique may downstage the surgical procedure necessary (see surgical section of this article).53 Even with CT imaging, it may be difficult to differentiate the uninfected phlegmonous mass of loops of adherent bowel from an early abscess. Table 2. HELPFUL CLUES ON CONTRAST ENEMA TO SUGGEST THE DIAGNOSIS OF DIVERTICULITIS
Diverticulitis Presence of diverticula plus Segmental narrowing with thickened and tethered mucosa Extraluminal mass effect Mural or extraluminal extravasation of contrast Free air (delineation of both outer and inner bowel wall-Rigler's sign) Stricture <3 cm length, usually collaring at both ends, cancer 3-6 length-diverticular disease 6-10 cm length-Crohn's, ischemia Splenic Flexure Common site for ischemia Rare involvement in diverticulitis Adapted from Marshak RH: Granulomatous colitis in association with diverticula. N Engl J Med 285:1080,1970; with permission.
1154
FREEMAN & McNALLY
Figure 1. See legend on opposite page
DIVERTICULITIS
1155
Perforation and Peritonitis
Free perforation into the peritoneal cavity results in frank peritonitis. Pain becomes severe with signs of peritoneal guarding, fever, tachycardia, elevation of white blood count, rebound, and percussion tenderness. Most patients are toxic and require prompt diagnosis and surgical intervention. Free peritoneal air seen on plain roentgenograms of the abdomen is uncommon in diverticulitis, as the perforations are usually microscopic. Certainly, perforated viscus from ulcer diathesis is much more common and should be considered the more likely diagnosis when this finding is encountered. If pneumoperitoneum is seen with diverticulitis, then the leak is inordinately large and prompt surgical intervention is usually indicated. UNCOMMON MANIFESTATIONS AND ASSOCIATIONS OF DIVERTICULITIS Arthritis and Pyoderma Gangrenosum
Klein and coworkers28 have recently reported on three elderly personS presenting with arthritis and pyoderma gangrenosum discovered to be an extra-intestinal manifestation of diverticulitis. All of the patients had failed maximal medical therapy including systemic and intralesional steroids and immunosuppressive therapy. Segmental resection of the involved colon was effective in eliminating the arthritis and pyoderma gangrenosum in all patients with follow-up to 38 months. Irtflammatory bowel disease was incorrectly diagnosed in all, based on radiographic and endoscopic findings of stricture and mucosal edema and erythema. Orthopedic Complications
Although up to 10% of persons with diverticulosis will ultimately suffer an episode of diverticulitis, it is rare to see retroperitoneal perforation. Haiart and associates20 reported on five cases of diverticulitis presenting with only leg pain. Of the 15 cases of thigh abscess or emphysema reported due to diverticular disease, 70% died. 2o,55 The mortality is in part due to the delayed recognition and inadequate treatment. The diagnosis of retroperitoneal perforation should be entertained in patients
Figure 1. Computerized tomogr.aphy of the lower abdomen and pelvis. A large hypodense abscess is seen in the left pelvis (A). Percutaneous catheter and wire are placed into the abscess cavity (B). Percutaneous indwelling stent placed into the evacuated abscess cavity (C). (Courtesy of James Luethke, MD.)
1156
FREEMAN & McNALLY
with unexplained symptoms of the leg, especially if accompanied by fever and leukocytosis. Early diagnosis may prevent the complication of emphysema of the leg. Once this has developed, fecal diversion, wide debridement, and broad-spectrum antibiotics are mandatory. Renal Disease and Diverticulosis
The association between diverticulosis coli and renal disease is an important one. Life-threatening complications of diverticulitis are much more common among renal patients with adult polycystic kidney disease (ADPCKD),49 chronic hemodialysis or peritoneal dialysis,15, 57 and postrenal transplantation? Immunosuppression is thought to be partially responsible. Surgical resection of the involved colon before renal transplant or initiation of CAPD is reasonable in these patients after the first episode of symptomatic diverticulitis. Diverticulitis; Corticosteroids and Nonsteroidal Antiinflammatory Drugs
There have been numerous reports of an association between the initiation of high-dose steroids and the development of acute diverticulitis. It has been hypothesized that the inhibition of epithelial renewal predisposes to a bacterial breach of the diverticular mucosa. 56 Whether corticosteroids actually cause diverticulitis is debatable; however, the ability of prednisone to disguise the severity of peritoneal findings in frank diverticular perforation should be emphasized. A recent case controlled study by Campbell and Steele showed that severe complications of diverticulitis are significantly more common among persons ingesting nonsteroidal anti-inflammatory drugs (NSAIDs).8 The authors hypothesized ingestion of NSAIDs could mollify or mask early symptoms of mild diverticulitis, hence delaying presentation. This association requires further confirmation, but the results are so striking that it deserves our attention. DIAGNOSTIC EVALUATIONS Contrast Enema
The safety and utility of contrast enema to evaluate acute diverticulitis is controversia1.6, 26 Barium contrast is generally avoided because a free leak could cause severe peritonitis. However, many radiologists have shown that prudent use of this examination can be safely conducted and provide useful information. 16 If indeed a contrast enema is needed, substitution of water soluble contrast logically eliminates the risk of barium. The typical findings of diverticulitis and the radiographic fea-
DIVERTICULITIS
1157
tures distinguishing diverticulitis from inflammatory bowel disease, colon cancer, and ischemic bowel disease are cited in Table 2 and shown in Figures 2 through 4. The diagnosis of diverticulitis is a clinical one that must be differentiated from other intestinal, genitourinary, gynecologic, and neoplastic conditions that can closely mimic diverticulitis. The accuracy of laboratory and clinical findings to correctly diagnose diverticulitis was prospectively evaluated by Hiltuten and coworkers. 22 They studied 53 patients with a strongly suspected clinical diagnosis of diverticulitis with water soluble contrast enema. Surprisingly, the clinical diagnosis of diverticulitis was confirmed in only 47% (25 of 53) of patients. Normal contrast studies were seen in a quarter of patients, whereas 1 had ischemic colitis, 3 had colon cancer, and the remainder had nondiverticular causes for their symptoms. No study-related complications occurred. These results suggest water-soluble contrast enema examination can be a safe and useful adjunct in the evaluation of patients with suspected mild to moderate diverticulitis.
Figure 2. Contrast enema stutly shows colonic diverticuli with strictu ring of the descending colon (A). Magnified view of colonic stricture with extrinsic narrowing caused by peridiverticular abscess (8). Mucosal pattern consistent with diverticulitis: tethered mucosa and a trace of contrast extravasation at the base of the stricture on the right.
1158
FREEMAN & McNALLY
Figure 3. Contrast enema study of the colon showing extensive diverticuli in the sigmoid colon with strictu ring (A). Magnified view of involved sigmoid showing extravasation and tracking of contrast parallel to the colon (B). (Courtesy of John C. Lemon, MD.)
Computerized Tomography
Computerized tomography (CT) has been shown to be as accurate or superior to contrast enemas in the diagnosis of acute diverticulitisY' 37,52 CT has the additional advantage of directly delineating extraluminal complications of diverticulitis and identifying patients with nondiverticular causes of symptoms, for example, colonic ischemia, pancreatitis, mesenteric thrombosis, and tubo-ovarian abscess. For these reasons, many centers have adopted abdominal CT scanning as the diagnostic
DIVERTICULITIS
1159
Figure 4. Contrast enema study showing accumulation of contrast anterior to the rectum and a communicating sigmoid-vaginal fistula. (Courtesy of John C. Lemon, MD.)
test of choice in the evaluation of acute diverticulitis. eT criteria used for diagnosis of acute diverticulitis include localized colonic wall thickening (>5 mm) and inflammation of pericolic fat (poorly marginated, stranding, increased attenuation), or localized wall thickening and presence of pericolic abscess. Ultrasonography
Verbanck and associates59 have shown that ultrasound can also be a helpful test in the evaluation of acute diverticulitis. In their hands, sonography had a sensitivity and specificity of 84% and 80%, respectively. Importantly, false-negative examinations were encountered in 15% of the 54 patients examined. Wilson and Toi62 have defined the sonographic diagnosis of diverticulitis by the presence of two of the following: focal colonic wall thickening (>4 mm), inflamed diverticula, inflammatory changes in the pericolic fat, intramural or pericolic inflammatory mass, and intramural fistulas. 62 The effectiveness of ultrasound is examiner dependent, and reproduction of Verbanck's success in evaluation of diverticular disease may be difficult without a capable and interested ultrasonographer.
1160
FREEMAN & McNALL Y
Endoscopy Known acute diverticulitis is generally considered a contraindication to performance of colonoscopy or flexible sigmoidoscopy. The need to insufflate the bowel during these examinations has the risk of worsening any diverticular perforation. Endoscopic evaluation is helpful when the diagnosis of diverticulitis is uncertain and other diagnoses are entertained such as obstructing carcinoma, ischemic bowel, inflammatory bowel disease, and infectious colitis. Under these circumstances, flexible sigmoidoscopy should be conducted by an experienced endoscopist with minimal use of insufflation and only careful passage of the instrument under direct visualization (no slide-by maneuver). Endoscopic examination should be terminated if an edematous or angulated segment cannot be easily passed. The endoscopic findings of diverticulitis include: inability to pass the instrument due to spasm or stricture, peridiverticular erythema, edema, or pus.
TREATMENT Management of a patient diagnosed as having diverticulitis varies according to the severity of the symptoms, duration of the illness, comorbid diseases, and the patient's underlying immune competency. Fortunately, most episodes of diverticulitis are of mild to moderate severity, peridiverticulitis with or without localized abscess, and will resolve satisfactorily with medical management. The most mild cases can be handled adequately on an outpatient basis by means of a clear liquid diet and oral antibiotics (e.g., TMP-SMX plus metronidazole). Many patients, however, should be hospitalized because of the need to provide gastrointestinal tract rest (NPO), intravenous fluids and antibiotics, and perhaps nasogastric suction if the patient is vomiting or has abdominal distention. Hospitalization also allows for frequent reassessment of the patient necessary in the first 48 to 72 hours following diagnosis. Antibiotic selection should provide coverage for enteric gram-negative organisms at a minimum, and often coverage for anaerobic organisms is added (Table 3). Cefoxitin 2 g every 8 hours as a single agent is often recommended for milder disease. An amino glycoside (gentamicin or tobramycin 3 to 5 mg/ kg every 8 hours) with clindamycin 300 to 600 mg, or metronidazole 500 mg, every 6 hours is an adequate regimen for more severe disease. A recent randomized, prospective, multicenter trial demonstrated that a single agent, cefoxitin, was as effective in treating patients with moderately severe diverticulitis as the combination of gentamycin and clindamycin. 27 Most patients correctly diagnosed with diverticulitis and treated medically will improve over 48 to 72 hours with a decrease in fever, leukocytosis, and abdominal pain. Failure to improve after this period of observation or a worsening course despite maximizing medical therapy are indications for abandoning this approach and considering surgery as an alternative.
Table 3. A GUIDE TO ANTIMICROBIAL THERAPY IN THE TREATMENT OF ACUTE DIVERTICULITIS Modifying Circumstances
Mild, nonperforating No high-risk factors
Moderately ill, possible local abscess ± high risk factors
Severely ill, toxic, peritonitis
Etiology
Aerobes E. coli Klebsiella sp. Streptococcus Proteus sp. Enterobacter sp. Anaerobes Bacteroides tragi/is Peptostreptococcus Peptococcus Clostridium Same + Pseudomonas aeruginosa
Same including Pseudomonas aeruginosa
First Choice
Second Choice
TMP/SMX+ Metronidazole
Ciprofloxacin or cephalexin for TMP/SMX, Clindamycin for metronidazole
Outpatient, PO
Ampicillin + Aminoglycoside + Metronidazole or Imipenem Cilastatin or Ampicillin/Sulbactam or Cefoxitin or Ticarcillin clavulanate Same
Ciprofloxacin + Metronidazole
Inpatient, IV + CT + Abscess Catheter drainage Consider surgery
Same
Adapted from Sanford JP: Guide to Antimicrobial Therapy. Dallas, TX, Antimicrobial Therapy, Inc., 1993, p 11; with permission .
..... ..... 0'\
.....
Comment
Inpatient, IV + CT Consider early surgery
1162
FREEMAN & McNALLY
The indications for surgery for diverticulitis are determined by the particular clinical situation of each patient. Indications for surgery are listed in Table 4. It has been estimated that 20% of patients developing diverticulitis will eventually require surgery.9 With increasing numbers of episodes, the complication rate and mortality rate increases significantly as wel1. 43 For patients for whom a poor long-term prognosis can be anticipated, elective surgery, as in many other situations, is advisable if possible. Patient morbidity and mortality will be much enhanced. Recurrent episodes beyond the initial episode is commonly felt to be an indication for resection. Septic complications such as abscess formation or free perforation are the most common reasons for surgery. Less commonly, obstruction, fistula formation, intractable pain, and inability to exclude colon cancer are reasons for surgery. Because diverticulitis can be unusually severe in certain subgroups, surgery is often recommended earlier than usual for: patients under 40 years of age, patients who are immune compromised (on steroids, post-organ transplant), and patients who have right-sided diverticulitis. Surgical options for diverticulitis include one-, two-, and three-stage procedures, depending on the indications and severity of the illness (Fig. 5). Under optimal conditions and circumstances, a patient requiring surgery can receive a resection of the area of inflammation with primary reanastomosis of the bowel to maintain normal integrity. The circumstances allowing such an approach include those cases in which surgery can be performed totally electively (obstruction from chronic stricture, intractable pain, recurrent episodes medically responsive). Also, a single stage procedure can perhaps be performed in a patient with a moderately severe episode in which the patient can be stabilized medically first, perhaps in recent years to include control of intra-abdominal abscess with eT or ultrasound-directed percutaneous drainage initially. Not uncommonly, a two-stage procedure is performed for the patient requiring urgent surgery not controllable by medical means above. This staged approach involves resection of the involved segment of bowel and diversion of the fecal stream via a proximal colostomy. The colostomy can be taken down and the integrity of the bowel restored following resolution of the infection and inflammation and recovery of the patient, commonly within 3 to 6 months. Occasionally, in the most desTable 4. INDICATIONS FOR SURGERY FOR DIVERTICULITIS Absolute Complication of Disease Sepsis Fistula Obstruction Recurrent disease Failure to improve with medical therapy Clinical deterioration Failure to exclude carcinoma
Modifying Factors Chronic stricture Young age Steroid use/immune compromise Right-sided diverticulitis
DIVERTICULITIS
or
(ft~ '-j';:;
/;;::~
!
1163
tp,i}~1f/'
'i~(~~( j ~ ~
H:!
!:; (
C'ii /;J~~~~/
A
B
c
Figure 5. These drawings illustrate the various surgical options for treating complicated diverticulitis. A. One-stage operation includes resection of diseased bowel and reanastomosis to continue normal bowel continuity. B, Two-stage operation for more complicated disease. This involves fecal diversion via a proximal colostomy and resection of the diseased segment. The distal segment of the colon can be oversewn (Hartman pouch) or brought out as a mucous fistula. This is the operation of choice and most frequently performed operation for diverticulitis complicated by abscess today. C, Three stage operation involves fecal diversion and simple drainage of the involved area at first. Later, the involved area is resected at a second operation and a reanastomosis of the segment is performed, leaving the suture line protected by the diverting colostomy. At a third surgery, the colostomy is taken down and bowel continuity is re-established. (Adapted from Reve RV, Nahrwold DL: Diverticular disease. Curr Probl Surg 26:170, 1989; with permission.)
perate circumstances, and when injury to vital abdominal structures such as major vessels and ureters is believed to be at significant risk due to the extent of inflammation, a three-stage procedure is performed. In this approach, the initial surgery will include a diverting colostomy and simple drainage of the area of involvement. At a second operation within 2 to 8 weeks, as determined by the patient's clinical course, the involved segment of bowel is resected. An anastomosis restoring bowel integrity is performed while maintaining a diverting colostomy; at a third surgery, within 2 to 4 weeks, the colostomy is taken down and normal integrity
1164
FREEMAN & MeN ALLY
of the bowel is restored. The three-stage approach was the standard approach for much of the 20th century but large reviews 13, 17 published in the past two decades have convincingly established the superiority of the two-stage procedure involving early resection of the involved segment. Mortality from the three-stage approach ranges from 12% to 32% whereas mortality for the two-stage procedure ranges from 1% to 12%?' 17 The two-stage procedure is presently considered to be the procedure of choice for treatment of perforated diverticulitis. Special Considerations
Management of fistulous complications of diverticulosis is a management problem with which clinicians occasionally are faced. The most common fistulous complication is the colo-urinary bladder or colovesical fistula, making up two thirds of all such complications.64 Other types of fistulae, in order of decreasing frequency are colocutaneous fistula, colovaginal fistula, and coloenteric fistula. 14 Colovesical fistula occurs with much greater frequency in men than women. The reasons for this surprising difference are unclear but the presence of a uterus in the female may offer some protection to the bladder. Miller36 pointed out that 61% of colovesical fistulas in women occurred in women who had undergone a hysterectomy. These fistulas are diagnosed by symptoms of recurrent urinary infections, fecaluria, and occasionally pneumaturia. Demonstration of the fistula can be difficult and the means of diagnosis were discussed earlier in this article. It is generally held that a well-documented colovesical fistula should be treated with surgery. Occasionally, in the high risk patient who is tolerating the condition with minimal symptoms, the condition can be treated nonsurgically.35 Surgery can be performed as a one-stage procedure in 90% of patients with very low mortality.46 Colovaginal fistulas and colocutaneous fistulas are also commonly treated with surgery with good success and low mortality but some surgeons find that these fistulae often will close with conservative medical management. 35 Those coloenteral fistulas which are sufficiently symptomatic to require surgery can usually be performed as a one-stage procedure with an en-block resection of the involved segment of the colon and small intestine. 46 CONCLUSIONS
While the majority of elderly Americans have diverticulosis, fortunately a small minority suffer the complication of diverticulitis. Most patients with this disease are able to be successfully treated medically by means of antibiotics and bowel rest, perhaps to include percutaneous catheter drainage of localized abscess. Some patients, however, are ill enough that surgical therapy is required that may be accomplished in a
DIVERTICULITIS
1165
single stage or require up to three separate procedures. Interesting new information regarding this well-known disease have been discussed: inflammatory bowel disease-like extraintestinal manifestations such as pyoderma gangrenosum and arthritis are now reported to be associated with diverticulitis; the association of unexplained back or leg pain and fever may suggest a retroperitoneal perforation and abscess from diverticulitis; not only corti co steroids, but NSAIDs may place a patient at higher risk for diverticulitis and its complications. Diverticulitis is a disease well known to clinicians which still demands understanding and careful good judgement for good patient outcome. The disease continues to offer challenging problems for the internist as well as the surgeon. References 1. Abramson ST, Berdon WE, Laffey K, et al: Colonic diverticulosis in young patients with chronic renal failure and transplantation. Pediatr Radiol 21:352-354, 1991 2. Adachi A, Gold M: Vaginography for enterovaginal fistulae. Am J Obst Gynecol 131:227-228,1978 3. Adams DB, Perry TG: Tandem colovaginoscopy in the diagnosis of colovaginal fistula. Dis Colon Rectum 31:653-654, 1988 4. Almy TP, Howell DA: Medical progress: Diverticular disease of the colon. N Engl J Med 302:324-331, 1980 5. Arsura EL: Corticosteroid-associated perforation of colonic diverticula. Arch Intern Med 150:1337-1338, 1990 6. Balthazar El, Megibow A, Schinella RA, et al: Limitations in the CT diagnosis of acute diverticulitis: Comparison of CT, contrast enema, and pathologic findings in 16 patients. Am J RoentgenoI154:281-285, 1990 7. Bohrer SP, Lewis EA: Diverticula of the colon in Ibadan. Nigeria. Trop Geogr Med 26:9-14,1974 8. Campbell K, Steele RJC: Non-steroidal anti-inflammatory drugs and complicated diverticular disease: A case-controled study. Br J Surg 78:190-191, 1991 9. Chappuis CW, Cohn I Jr: Acute colonic diverticulitis. Surg Clin North Am 68:301-313, 1988 10. Chia JG, Wilde Cc, Ngoi SS, et al: Trends in diverticular disease of the large bowel in a newly developed country. Dis Colon Rectum 34:498-501,1991 11. Cho KC, Morehouse HT, Alterman DD, et al: SigmOid diverticulitis: Diagnostic role of CT-comparison with barium enema studies. Radiology 176:111-115, 1990 12. Coder A: Steroids, non-steroidal anti-inflammatory drugs and serious complications of diverticular disease. Br Med J 295:1238, 1987 13. Eng K, Ranson JH, Localeo GA: Resection of the perforated segment: A significant advance in the treatment of diverticulitis with free perforation of abscess. Am J Surg 133:67-72, 1977 14. Fazio VW, Church JM, Jagelman DG, et al: Colocutaneous fistulas complicating diverticulitis. Dis Colon Rectum 30:89, 1987 15. Galbraith P, Bagg MN, Schabel SI, et al: Diverticular complications of renal disease. Gastrointest RadioI15:259-262, 1990 16. Greenall Ml, Levine AW, Nolan DT: Complications of diverticular disease: A review of the barium enema findings. Gastrointest RadioI8:353-358, 1983 17. Greif JM, Fried G, McSherry CK: Surgical treatment of perforated diverticulitis of the Sigmoid colon. Dis Colon Rectum 23:483-487, 1980 18. Grisson R, Snyder TE: Colovaginal fistula secondary to diverticular disease. Dis Colon Rectum 34:1043-1049,1991 19. Hafner CD, Ponka LL Brush BE: Genitourinary manifestations of diverticulitis of the colon: A study of 500 cases. JAMA 179:76, 1962
1166
FREEMAN & MeN ALL Y
20. Haiart DC, Stevenson P, Hartley RC: Leg pain: An uncommon presentation of perforated diverticular disease. J R Coll Surg Edinb 34:17-20, 1989 21. Hannan CE, Knightly JJ, Coffey RJ: Diverticular disease of the colon in the younger age group. Dis Colon Rectum 4:419-423,1961 22. Hiltuten KM, Kolehmainen H, Vuorinen T, et al: Early water-soluble contrast enema in the diagnosis of acute colonic diverticulitis. Intern J Colorect Dis 6:190-192, 1991 23. Horner JL: Natural history of diverticulosis of the colon. Am J Dig Dis 5:343-350,1958 24. Hulnick DH, Megibow AI, Balthazar EJ, et al: Computerized tomography in the evaluation of diverticulitis. Ann Surg 204:128-132,1984 25. Ihekwaba FN: Diverticular disease in black Africa. J R Coll Surg Edinb 37:107-109,1992 26. Johnson CD, Baker ME, Rice RP, et al: Diagnosis of acute colonic diverticulitis: Comparison of barium enema to CT. Am J RoentgenoI148:541-546, 1987 27. Kellum JM, Sugerman HJ: Randomized, prospective comparison of cefoxitin and gentamicin-clindamycin in the treatment of acute colonic diverticulosis. Clin Ther 14:376384, 1992 28. Klein S, Mayer L, Present DH, et al: Extraintestinal manifestations in patients with diverticulitis. Ann Intern Med 108:700-702, 1988 29. Markham NI, Li AKC: Diverticulosis of the right colon-experience from Hong Kong. Gut 33:547-549,1992 30. Marshak RH: Granulomatous colitis in association with diverticula. N Engl J Med 285:1080, 1970 31. McConnell DB, Sasaki TM, Vetto RM: Experience with colovesical fistula. Am J Surg 140:80,1980 32. Mendeloff AI: A critique of "fiber defiency." Am J Dig Dis 21:109-112,1976 33. Mendeloff AI: Dietary fiber and gastrointestinal diseases. Med Clin North Am 62:165171,1978 34. Mendeloff AI: Thoughts on the epidemiology of diverticular disease. Clin Gastroenterol 15:855-877,1986 35. Milesa WJ, Joehl RI, Rege RV, et al: One stage resection and anastomosis in the management of colovesical fistula. Am J Surg 153:75, 1987 36. Miller RE: Role of hysterectomy in predisposing the patient to sigmoidovesical fistula complicating diverticulitis. Am J Surg 147:660, 1984 37. Morris J, Stellato JA, Haaga JR, et al: The utility of computerized tomography in colonic diverticulitis. Ann Surg 204:128-132,1986 38. Omojola MF, Mangete E: Diverticula of the colon in three Nigerian siblings. Trop Geogr Med 10:45-57, 1988 39. Ouriel K, Schwartz SI: Diverticular disease in the young patient. Surg Gynecol Obstet 156:1-5,1983 40. Painter NS: Diverticular disease of the colon. Br Med J 3:475-479,1968 41. Painter NS, Burkitt DP: Diverticular disease of the colon: A deficiency disease of western civilization. Br Med J 2:450-454, 1971 42. Painter NS, Truelove SC: The intraluminal pressure patterns in diverticulosis of the colon: Resting pattern of pressure. Gut 5:201-203,1964 43. Parks TG: Natural history of diverticular disease of the colon. Clin Gastroenterol 4:53, 1975 44. Parks TG: Natural history of diverticular disease of the colon. A review of 521 cases. Br Med J 4:693, 1969 45. Parks TG: Post-mortum studies on the colon with special reference to diverticular disease. Proc R Soc Med 61:932-934,1968 46. Reve RV, Nahrwold DL: Diverticular disease. Curr Prob Surg 26:136, 1989 47. Rosen AM, Fleischer DE: Lower GI bleeding: Updated diagnosis and management. Geriatrics 44:49-60, 1989 48. Ryan P: Two kinds of diverticular disease. Ann R Coll Surg Engl 73:73-79, 1991 49. Scheff RT, Zuckerman G, Harter H, et al: Diverticular disease in patients with chronic renal failure due to polycystic kidney disease. Ann Intern Med 92:202-204, 1980 50. Scully RE, Mark El, McNeely WF, et al: Case records of the Massachusetts General Hospital. N Engl J Med 327:40-44,1992 51. Sikirov BA: Etiology and pathogenesis of diverticulosis coli: A new approach. Medical Hypothesis 26:17-20, 1988
DIVERTICULITIS
1167
52. Smith TR, Cho Ke, Morehouse HT, et al: Comparison of computed tomography and contrast enema evaluation of diverticulitis. Dis Colon Rectum 33:1-6,1990 53. Stabile BE, Puccio E, vanSonnenberg E, et al: Preoperative percutaneous drainage of diverticular abscess. Am J Surg 159:99-111, 1990 54. Sugihara K, Muto T, Morioka Y, et al: Diverticular disease of the colon in Japan: A review of 615 cases. Dis Colon Rectum 27:531,1984 55. Terry JH: Unusual cases of perforated diverticulitis of colon. J Fla Med Assoc 77:814816, 1990 56. Toombs JP, Caywood DD, Lipowitz AJ, et al: Colonic perforation following neurosurgical procedures and corticosteroid therapy in four dogs. J Am Vet Med Assoc 177:6872, 1980 57. Tranaeus A, Heimburger 0, Granqvist S: Diverticular disease of the colon: A risk factor for peritonitis in continuous peritoneal dialysis. Nephrol Dial Transplant 5:141-147, 1990 58. Vajrabukka T, Saksornchai K, Jimakorn P: Diverticular disease of the colon in a far eastern community. Dis Colon Rectum 23:151, 1980 59. Verbanck I, Lambrecht 5, Ruteerts L, et al: Can sonography diagnose acute colonic diverticulitis in patients with acute intestinal inflammation? A prospective study. J Clin Ultrasound 17:661-666, 1989 60. Wehmann TW, Rongaus VA: Diverticular disease in young adults. J Am Osteopath Assoc 89:791-793, 1989 61. Weinrich I, Anderson D: Intraluminal pressure in the sigmoid colon. Patients with sigmoid diverticular and related conditions. Scand J GastroenteroI1l:581-586, 1976 62. Wilson SR, Toi A: The value of sonography in the diagnosis of acute diverticulitis of the colon. Am J RoentgenoI154:1199-1202, 1990 63. Wolf AV: Demonstration concerning pressure - tension relations in various organs. Science 115:243-244, 1952 64. Woods RI, Lavery le, Fazio VW, et al: Internal fistulas in diverticular disease. Dis Colon Rectum 31:591-596,1988
Address reprint requests to COL Stephen R. Freeman, MC, MD Department of Medicine Building 403-W Fitzsimons Army Medical Center Aurora, CO 80045-5001
0025-7125/93 $0.00
+ .20
DIVERTICULITIS COL Stephen R. Freeman, MC, MD, and LTC Peter R. McNally, MC, DO
Diverticulosis coli is one of the most common diseases seen in western civilization. In America, one third of the population will have diverticulosis coli by age 50 and approximately two thirds by the age of 80. 34,43 Fortunately, diverticulosis remains asymptomatic in the majority, with only 10% to 20% of patients suffering complications of diverticulitis or diverticular hemorrhage during their lifetime. 4,47 The precise pathogenesis of diverticular disease is unknown; however, aging,23 elevation of colonic intraluminal pressure,42 and decreased dietary fiber appear related. 33 In western societies, the prevalence of diverticular disease abruptly increased 30 years after the introduction of grain milling factories, which greatly decreased the amount of dietary grain fiber. 41 Other dietary factors such as increased consumption of beef, beef fat, and salt are also suggested as causative factors.32 Decreased luminal fiber lowers stool volume and requires more colonic segmentation to propel the material aborally.40 Segmentation generates greater intraluminal pressures and may predispose to formation of diverticula. The colonic wall is inherently weakest where nutrient arteries penetrate the muscularis propria and diverticula typically arise there. Among European decendents, colonic diverticula are most commonly found in the sigmoid colon (over 85%)? The smaller luminal diameter of the sigmoid and resultant increase in wall tension is thought to be responsible for this,61,63 Defecation using standard western society toilets generates much greater intra colonic pressures than seen in the third world where knee chest position of defecation and pit latrines are common. This has led some to suggest the unappealing notion that the use of toilets are in part responsible for the geographic disparity in the prevalence of diverticuloSiS,51
From the Department of Medicine, Gastroenterology Service, Fitzsimons Army Medical Center, Aurora, Colorado MEDICAL CLINICS OF NORTH AMERICA VOLUME 77 • NUMBER 5 • SEPTEMBER 1993
1149
1150
FREEMAN & McNALLY
Permeation of western culture and diet in parts of the Far East is thought to be responsible for the increase in diverticulosis seen. 54 The 20% prevalence of diverticulosis seen in patients undergoing routine barium enema examination in Singapore parallels that seen in many western countries.lO Genetic or other environmental factors must also be important in the evolution of diverticular disease because diverticula are site specific to the right colon among Asians, whereas diverticula have a proclivity for the sigmoid and left colon and occur a decade later among occidentals.9, 44, 58 Complications of diverticulosis include hemorrhage and diverticulitis. It is interesting that these complications are mutually exclusive. Patients with diverticular hemorrhage do not generally develop diverticulitis (perforation, stricture, fistulae) and vice versa. 48 The diverticular complication of gastrointestinal hemorrhage are reviewed elsewhere in this issue. CLINICAL PRESENTATION
The signs and symptoms of diverticulitis vary widely, but abrupt onset of abdominal pain and alteration in bowel pattern are present in nearly all. Mild early acute diverticulitis, peridiverticulitis, is characterized as circumscribed, abdominal pain and tenderness. Usually the pain is unremitting and localized to the left lower quadrant; however, inflammation can occur anywhere that diverticula are foufld. Hence, inflamed diverticula of the transverse colon may simulate ulcer pain and diverticulitis of the cecum and redundant sigmoid may appear clinically identical to appendicitis. The pain of diverticulitis is often accompanied by generalized malaise and elevation in peripheral white blood count. The severity of pain and the persistence of symptoms, as well as signs of inflammation (fever, white count, and sedimentation rate) help to distinguish colonic spasm from diverticulitis. Still, it is often difficult to distinguish patients with mild peridiverticulitis from those with irritable bowel syndrome with coincidently discovered diverticula. Importantly, a patient young of age «40 years) should not preclude the consideration of diverticulitis from the differential diagnosis of abdominal pain. 60 Episodes of diverticulitis appear to be more virulent in the young and very elderly, with surgical intervention often necessary?1,39,50 If peridiverticulitis progresses, then localized abscess and phlegmonous reaction may occur. Pain and tenderness continue and a palpable mass may become evident. Plain films of the abdomen may show signs of obstruction, mass effect, or ileus. Systemic signs of infection may become pronounced, such as fever and elevated white count. Unlike occidentals, right sided diverticulosis is typical among Asians (>75%) and acute diverticulitis should be considered in those presenting with right-sided abdominal pain and fever. 29 Native Africans were once thought to be immune to this disorder; however, adoption of western culture and diet have been paralleled by an increase in the prevalence of diverticulitis in the sub-Saharan Desert?' 25, 38
DIVERTICULITIS
1151
It must be emphasized that the abdominal examination in diverticulitis may be deceptively unremarkable in the elderly and in persons on corticosteroids. s, 12 Greater reliance on computerized tomography to guide the management of these patients is reasonable because delay in the diagnosis of free perforation or abscess may increase operative mortality to approximately 50%. Palpation of an abdominal mass in any patient with clinically suspected diverticulitis is an indication for computerized tomography. Other signs and symptoms of diverticulitis are highly variable and nonspecific. In the past, obstipation was emphasized as a symptom of diverticulitis, but many patients actually have diarrhea. Obstipation may also be due to other nondiverticular disease such as obstructing colon carcinoma. Frank rectal bleeding is not seen with diverticulitis and should be ascribed to other causes, for example, hemorrhoids, polyps, tumors, arteriovenous malformations (AVM's), or arterial bleeding of painless diverticulosis. Cautious sigmoidoscopic examination may be very helpful in this circumstance. A practical approach to the patient with suspected acute diverticulitis is presented in Table 1. COMPLICATIONS OF DIVERTICULITIS Fistula
Chronic diverticulitis is associated with an inflammatory reaction that can adhease intra-abdominal organs to the colon. With repeated attacks of diverticulitis, a fistulous tract can form. Fistulous communications between bowel, urinary bladder, integument, pelvic floor, and vagina have been reported. Colon to urinary bladder (colovesicular) fistula is the most common form of diverticular fistula. 19 This complication is seen almost exclusively in men. Pneumaturia is an uncommon, but a pathognomonic feature of colovesicular fistula. More commonly, the diagnosis should be suspected in persons with recurrent urinary tract infections, especially if temporally associated with diverticulitis or characterized by multiple organisms. The fistulous communications can be very small. Reflux of contrast into the urinary bladder during contrast enema confirms the diagnosis, but is not often positive. Cystoscopy may show focal cystitis, but the fistulous communication may be obscured by chronic inflammation. Surgical correction is usually indicated for all colovesicular fistulae. Technical aspects of this procedure are described under the treatment of diverticular complications. Complicated diverticular disease is the most common cause of colovaginal fistulas 18 and they are seen almost exclusively in women with prior hysterectomies (80%).64 Other causes include pelvic irradiation, regional ileitis, gynecologic surgery, and pelvic abscess of any source. Clinically, colovaginal fistula may present variably from persistent, scant vaginal discharge to severe vaginitis. Flatus vaginalis and feculent dis-
1152
FREEMAN & McNALLY
Table 1. A PRACTICAL APPROACH TO THE EVALUATION AND DIAGNOSIS OF ACUTE DIVERTICULITIS Clinical history and physical examination Usually over 60 years of age LLQ localized tenderness and unremitting abdominal pain Fever Leukocytosis DDx Elderly Ischemia Carcinoma Volvulus Obstruction Penetrating ulcer Nephrolithiasis/urosepsis
Middle Aged and Young Appendicitis Salpingitis Inflammatory bowel Penetrating ulcer Urosepsis
Qualifiers Extremes of age (more virulent), oriental ancestry (right sided symptoms), corticosteroids, immunosuppressives, and chronic renal failure (abdominal examination insensitive). Evaluations Plain X-rays Good initial first step; may show ileus, obstruction, mass effect, ischemia, perforation. Contrast Enema For mild-to-moderate cases of diverticulitis when the diagnosis is in doubt water soluble contrast examination is safe and helpful, otherwise delay the examination for 6 to 8 weeks. Endoscopy Acute diverticulitis is a relative contraindication to endoscopy-must exclude perforation first. Examination only when the diagnosis is in doubt (rectal bleeding, anemia) to exclude the possibility of ischemic bowel, Crohn's disease, carcinoma. CT scan Very helpful in staging the degree of complications and evaluating for other diseases. Should be considered in all cases of diverticulitis with a palpable mass or clinical toxicity, failure of medical therapy, orthopedic complications, and corticosteroid use. The test of choice to evaluate acute diverticulitis in most centers. Ultrasound Can be a safe and helpful non invasive test to evaluate acute diverticulitis. Examinations suboptimal due to intestinal gas in 15%, very institution dependent.
charge are pathognomonic but less commonly seen. Usually symptoms of colovaginal fistula become manifest after an attack of diverticulitis. If symptoms of a vaginal fistula occur during an attack of acute diverticulitis, computerized tomography can be safely performed and can identify the fistula in up to 20% of cases,z4 The size of the fistula can be small and difficult to identify. Conventional methods used to identify the fistulous tract include barium enema and examination for dark vaginal discharge after oral charcoal. Adachi and Gold2 have reported the utility of contrast vaginography to identify occult fistulous communications. The technique requires insertion of a 30 mL balloon into the vagina. The balloon is filled and then contrast infused while lateral, oblique, and supine radiographs are taken to identify the fistulous connection. Simultaneous fiberoptic vaginoscopy and colonoscopy has also been recently shown to be a helpful technique in the identification of obscure colovaginal fistulae. 3 Regardless of the size of the fistula or the severity of symptoms, the fistula will persist until surgically corrected. Operations for complicated diverticulitis include resection of the diseased bowel with primary re-
DIVERTICULITIS
1153
anastomosis or a staged procedure as outlined in this article under surgical management of complicated diverticulitis. Obstruction
Muscular wall thickening, myocosis coli, is commonly seen in sigmoid diverticulosis. 45 With repeated episodes of subclinical diverticulitis, the colon becomes fixed, fibrotic, and stenosed. Colonic obstruction is most predisposed to the sigmoid where angulation is greatest. It is essential to exclude other causes of colonic stricture, such as carcinoma, Crohn's disease, and ischemia. Clues to the cause of colonic stricture by contrast radiography are cited in Table 2. If the stricture cannot, however, be definitively cleared by endoscopy or if the patient is symptomatic, then surgical resection is indicated. Abscess
Failure of any patient with acute diverticulitis to respond to medical therapy within 24 to 48 hours or palpation of an abdominal mass should always raise the suspicion of an intra-abdominal abscess. Abdominal computerized tomography or ultrasonography are excellent methods of evaluation for this complication. If a contained abscess cavity is identified, percutaneous drainage may be used to evacuate the cavity and augment medical therapy (Fig. 1). Successful utilization of this technique may downstage the surgical procedure necessary (see surgical section of this article).53 Even with CT imaging, it may be difficult to differentiate the uninfected phlegmonous mass of loops of adherent bowel from an early abscess. Table 2. HELPFUL CLUES ON CONTRAST ENEMA TO SUGGEST THE DIAGNOSIS OF DIVERTICULITIS
Diverticulitis Presence of diverticula plus Segmental narrowing with thickened and tethered mucosa Extraluminal mass effect Mural or extraluminal extravasation of contrast Free air (delineation of both outer and inner bowel wall-Rigler's sign) Stricture <3 cm length, usually collaring at both ends, cancer 3-6 length-diverticular disease 6-10 cm length-Crohn's, ischemia Splenic Flexure Common site for ischemia Rare involvement in diverticulitis Adapted from Marshak RH: Granulomatous colitis in association with diverticula. N Engl J Med 285:1080,1970; with permission.
1154
FREEMAN & McNALLY
Figure 1. See legend on opposite page
DIVERTICULITIS
1155
Perforation and Peritonitis
Free perforation into the peritoneal cavity results in frank peritonitis. Pain becomes severe with signs of peritoneal guarding, fever, tachycardia, elevation of white blood count, rebound, and percussion tenderness. Most patients are toxic and require prompt diagnosis and surgical intervention. Free peritoneal air seen on plain roentgenograms of the abdomen is uncommon in diverticulitis, as the perforations are usually microscopic. Certainly, perforated viscus from ulcer diathesis is much more common and should be considered the more likely diagnosis when this finding is encountered. If pneumoperitoneum is seen with diverticulitis, then the leak is inordinately large and prompt surgical intervention is usually indicated. UNCOMMON MANIFESTATIONS AND ASSOCIATIONS OF DIVERTICULITIS Arthritis and Pyoderma Gangrenosum
Klein and coworkers28 have recently reported on three elderly personS presenting with arthritis and pyoderma gangrenosum discovered to be an extra-intestinal manifestation of diverticulitis. All of the patients had failed maximal medical therapy including systemic and intralesional steroids and immunosuppressive therapy. Segmental resection of the involved colon was effective in eliminating the arthritis and pyoderma gangrenosum in all patients with follow-up to 38 months. Irtflammatory bowel disease was incorrectly diagnosed in all, based on radiographic and endoscopic findings of stricture and mucosal edema and erythema. Orthopedic Complications
Although up to 10% of persons with diverticulosis will ultimately suffer an episode of diverticulitis, it is rare to see retroperitoneal perforation. Haiart and associates20 reported on five cases of diverticulitis presenting with only leg pain. Of the 15 cases of thigh abscess or emphysema reported due to diverticular disease, 70% died. 2o,55 The mortality is in part due to the delayed recognition and inadequate treatment. The diagnosis of retroperitoneal perforation should be entertained in patients
Figure 1. Computerized tomogr.aphy of the lower abdomen and pelvis. A large hypodense abscess is seen in the left pelvis (A). Percutaneous catheter and wire are placed into the abscess cavity (B). Percutaneous indwelling stent placed into the evacuated abscess cavity (C). (Courtesy of James Luethke, MD.)
1156
FREEMAN & McNALLY
with unexplained symptoms of the leg, especially if accompanied by fever and leukocytosis. Early diagnosis may prevent the complication of emphysema of the leg. Once this has developed, fecal diversion, wide debridement, and broad-spectrum antibiotics are mandatory. Renal Disease and Diverticulosis
The association between diverticulosis coli and renal disease is an important one. Life-threatening complications of diverticulitis are much more common among renal patients with adult polycystic kidney disease (ADPCKD),49 chronic hemodialysis or peritoneal dialysis,15, 57 and postrenal transplantation? Immunosuppression is thought to be partially responsible. Surgical resection of the involved colon before renal transplant or initiation of CAPD is reasonable in these patients after the first episode of symptomatic diverticulitis. Diverticulitis; Corticosteroids and Nonsteroidal Antiinflammatory Drugs
There have been numerous reports of an association between the initiation of high-dose steroids and the development of acute diverticulitis. It has been hypothesized that the inhibition of epithelial renewal predisposes to a bacterial breach of the diverticular mucosa. 56 Whether corticosteroids actually cause diverticulitis is debatable; however, the ability of prednisone to disguise the severity of peritoneal findings in frank diverticular perforation should be emphasized. A recent case controlled study by Campbell and Steele showed that severe complications of diverticulitis are significantly more common among persons ingesting nonsteroidal anti-inflammatory drugs (NSAIDs).8 The authors hypothesized ingestion of NSAIDs could mollify or mask early symptoms of mild diverticulitis, hence delaying presentation. This association requires further confirmation, but the results are so striking that it deserves our attention. DIAGNOSTIC EVALUATIONS Contrast Enema
The safety and utility of contrast enema to evaluate acute diverticulitis is controversia1.6, 26 Barium contrast is generally avoided because a free leak could cause severe peritonitis. However, many radiologists have shown that prudent use of this examination can be safely conducted and provide useful information. 16 If indeed a contrast enema is needed, substitution of water soluble contrast logically eliminates the risk of barium. The typical findings of diverticulitis and the radiographic fea-
DIVERTICULITIS
1157
tures distinguishing diverticulitis from inflammatory bowel disease, colon cancer, and ischemic bowel disease are cited in Table 2 and shown in Figures 2 through 4. The diagnosis of diverticulitis is a clinical one that must be differentiated from other intestinal, genitourinary, gynecologic, and neoplastic conditions that can closely mimic diverticulitis. The accuracy of laboratory and clinical findings to correctly diagnose diverticulitis was prospectively evaluated by Hiltuten and coworkers. 22 They studied 53 patients with a strongly suspected clinical diagnosis of diverticulitis with water soluble contrast enema. Surprisingly, the clinical diagnosis of diverticulitis was confirmed in only 47% (25 of 53) of patients. Normal contrast studies were seen in a quarter of patients, whereas 1 had ischemic colitis, 3 had colon cancer, and the remainder had nondiverticular causes for their symptoms. No study-related complications occurred. These results suggest water-soluble contrast enema examination can be a safe and useful adjunct in the evaluation of patients with suspected mild to moderate diverticulitis.
Figure 2. Contrast enema stutly shows colonic diverticuli with strictu ring of the descending colon (A). Magnified view of colonic stricture with extrinsic narrowing caused by peridiverticular abscess (8). Mucosal pattern consistent with diverticulitis: tethered mucosa and a trace of contrast extravasation at the base of the stricture on the right.
1158
FREEMAN & McNALLY
Figure 3. Contrast enema study of the colon showing extensive diverticuli in the sigmoid colon with strictu ring (A). Magnified view of involved sigmoid showing extravasation and tracking of contrast parallel to the colon (B). (Courtesy of John C. Lemon, MD.)
Computerized Tomography
Computerized tomography (CT) has been shown to be as accurate or superior to contrast enemas in the diagnosis of acute diverticulitisY' 37,52 CT has the additional advantage of directly delineating extraluminal complications of diverticulitis and identifying patients with nondiverticular causes of symptoms, for example, colonic ischemia, pancreatitis, mesenteric thrombosis, and tubo-ovarian abscess. For these reasons, many centers have adopted abdominal CT scanning as the diagnostic
DIVERTICULITIS
1159
Figure 4. Contrast enema study showing accumulation of contrast anterior to the rectum and a communicating sigmoid-vaginal fistula. (Courtesy of John C. Lemon, MD.)
test of choice in the evaluation of acute diverticulitis. eT criteria used for diagnosis of acute diverticulitis include localized colonic wall thickening (>5 mm) and inflammation of pericolic fat (poorly marginated, stranding, increased attenuation), or localized wall thickening and presence of pericolic abscess. Ultrasonography
Verbanck and associates59 have shown that ultrasound can also be a helpful test in the evaluation of acute diverticulitis. In their hands, sonography had a sensitivity and specificity of 84% and 80%, respectively. Importantly, false-negative examinations were encountered in 15% of the 54 patients examined. Wilson and Toi62 have defined the sonographic diagnosis of diverticulitis by the presence of two of the following: focal colonic wall thickening (>4 mm), inflamed diverticula, inflammatory changes in the pericolic fat, intramural or pericolic inflammatory mass, and intramural fistulas. 62 The effectiveness of ultrasound is examiner dependent, and reproduction of Verbanck's success in evaluation of diverticular disease may be difficult without a capable and interested ultrasonographer.
1160
FREEMAN & McNALL Y
Endoscopy Known acute diverticulitis is generally considered a contraindication to performance of colonoscopy or flexible sigmoidoscopy. The need to insufflate the bowel during these examinations has the risk of worsening any diverticular perforation. Endoscopic evaluation is helpful when the diagnosis of diverticulitis is uncertain and other diagnoses are entertained such as obstructing carcinoma, ischemic bowel, inflammatory bowel disease, and infectious colitis. Under these circumstances, flexible sigmoidoscopy should be conducted by an experienced endoscopist with minimal use of insufflation and only careful passage of the instrument under direct visualization (no slide-by maneuver). Endoscopic examination should be terminated if an edematous or angulated segment cannot be easily passed. The endoscopic findings of diverticulitis include: inability to pass the instrument due to spasm or stricture, peridiverticular erythema, edema, or pus.
TREATMENT Management of a patient diagnosed as having diverticulitis varies according to the severity of the symptoms, duration of the illness, comorbid diseases, and the patient's underlying immune competency. Fortunately, most episodes of diverticulitis are of mild to moderate severity, peridiverticulitis with or without localized abscess, and will resolve satisfactorily with medical management. The most mild cases can be handled adequately on an outpatient basis by means of a clear liquid diet and oral antibiotics (e.g., TMP-SMX plus metronidazole). Many patients, however, should be hospitalized because of the need to provide gastrointestinal tract rest (NPO), intravenous fluids and antibiotics, and perhaps nasogastric suction if the patient is vomiting or has abdominal distention. Hospitalization also allows for frequent reassessment of the patient necessary in the first 48 to 72 hours following diagnosis. Antibiotic selection should provide coverage for enteric gram-negative organisms at a minimum, and often coverage for anaerobic organisms is added (Table 3). Cefoxitin 2 g every 8 hours as a single agent is often recommended for milder disease. An amino glycoside (gentamicin or tobramycin 3 to 5 mg/ kg every 8 hours) with clindamycin 300 to 600 mg, or metronidazole 500 mg, every 6 hours is an adequate regimen for more severe disease. A recent randomized, prospective, multicenter trial demonstrated that a single agent, cefoxitin, was as effective in treating patients with moderately severe diverticulitis as the combination of gentamycin and clindamycin. 27 Most patients correctly diagnosed with diverticulitis and treated medically will improve over 48 to 72 hours with a decrease in fever, leukocytosis, and abdominal pain. Failure to improve after this period of observation or a worsening course despite maximizing medical therapy are indications for abandoning this approach and considering surgery as an alternative.
Table 3. A GUIDE TO ANTIMICROBIAL THERAPY IN THE TREATMENT OF ACUTE DIVERTICULITIS Modifying Circumstances
Mild, nonperforating No high-risk factors
Moderately ill, possible local abscess ± high risk factors
Severely ill, toxic, peritonitis
Etiology
Aerobes E. coli Klebsiella sp. Streptococcus Proteus sp. Enterobacter sp. Anaerobes Bacteroides tragi/is Peptostreptococcus Peptococcus Clostridium Same + Pseudomonas aeruginosa
Same including Pseudomonas aeruginosa
First Choice
Second Choice
TMP/SMX+ Metronidazole
Ciprofloxacin or cephalexin for TMP/SMX, Clindamycin for metronidazole
Outpatient, PO
Ampicillin + Aminoglycoside + Metronidazole or Imipenem Cilastatin or Ampicillin/Sulbactam or Cefoxitin or Ticarcillin clavulanate Same
Ciprofloxacin + Metronidazole
Inpatient, IV + CT + Abscess Catheter drainage Consider surgery
Same
Adapted from Sanford JP: Guide to Antimicrobial Therapy. Dallas, TX, Antimicrobial Therapy, Inc., 1993, p 11; with permission .
..... ..... 0'\
.....
Comment
Inpatient, IV + CT Consider early surgery
1162
FREEMAN & McNALLY
The indications for surgery for diverticulitis are determined by the particular clinical situation of each patient. Indications for surgery are listed in Table 4. It has been estimated that 20% of patients developing diverticulitis will eventually require surgery.9 With increasing numbers of episodes, the complication rate and mortality rate increases significantly as wel1. 43 For patients for whom a poor long-term prognosis can be anticipated, elective surgery, as in many other situations, is advisable if possible. Patient morbidity and mortality will be much enhanced. Recurrent episodes beyond the initial episode is commonly felt to be an indication for resection. Septic complications such as abscess formation or free perforation are the most common reasons for surgery. Less commonly, obstruction, fistula formation, intractable pain, and inability to exclude colon cancer are reasons for surgery. Because diverticulitis can be unusually severe in certain subgroups, surgery is often recommended earlier than usual for: patients under 40 years of age, patients who are immune compromised (on steroids, post-organ transplant), and patients who have right-sided diverticulitis. Surgical options for diverticulitis include one-, two-, and three-stage procedures, depending on the indications and severity of the illness (Fig. 5). Under optimal conditions and circumstances, a patient requiring surgery can receive a resection of the area of inflammation with primary reanastomosis of the bowel to maintain normal integrity. The circumstances allowing such an approach include those cases in which surgery can be performed totally electively (obstruction from chronic stricture, intractable pain, recurrent episodes medically responsive). Also, a single stage procedure can perhaps be performed in a patient with a moderately severe episode in which the patient can be stabilized medically first, perhaps in recent years to include control of intra-abdominal abscess with eT or ultrasound-directed percutaneous drainage initially. Not uncommonly, a two-stage procedure is performed for the patient requiring urgent surgery not controllable by medical means above. This staged approach involves resection of the involved segment of bowel and diversion of the fecal stream via a proximal colostomy. The colostomy can be taken down and the integrity of the bowel restored following resolution of the infection and inflammation and recovery of the patient, commonly within 3 to 6 months. Occasionally, in the most desTable 4. INDICATIONS FOR SURGERY FOR DIVERTICULITIS Absolute Complication of Disease Sepsis Fistula Obstruction Recurrent disease Failure to improve with medical therapy Clinical deterioration Failure to exclude carcinoma
Modifying Factors Chronic stricture Young age Steroid use/immune compromise Right-sided diverticulitis
DIVERTICULITIS
or
(ft~ '-j';:;
/;;::~
!
1163
tp,i}~1f/'
'i~(~~( j ~ ~
H:!
!:; (
C'ii /;J~~~~/
A
B
c
Figure 5. These drawings illustrate the various surgical options for treating complicated diverticulitis. A. One-stage operation includes resection of diseased bowel and reanastomosis to continue normal bowel continuity. B, Two-stage operation for more complicated disease. This involves fecal diversion via a proximal colostomy and resection of the diseased segment. The distal segment of the colon can be oversewn (Hartman pouch) or brought out as a mucous fistula. This is the operation of choice and most frequently performed operation for diverticulitis complicated by abscess today. C, Three stage operation involves fecal diversion and simple drainage of the involved area at first. Later, the involved area is resected at a second operation and a reanastomosis of the segment is performed, leaving the suture line protected by the diverting colostomy. At a third surgery, the colostomy is taken down and bowel continuity is re-established. (Adapted from Reve RV, Nahrwold DL: Diverticular disease. Curr Probl Surg 26:170, 1989; with permission.)
perate circumstances, and when injury to vital abdominal structures such as major vessels and ureters is believed to be at significant risk due to the extent of inflammation, a three-stage procedure is performed. In this approach, the initial surgery will include a diverting colostomy and simple drainage of the area of involvement. At a second operation within 2 to 8 weeks, as determined by the patient's clinical course, the involved segment of bowel is resected. An anastomosis restoring bowel integrity is performed while maintaining a diverting colostomy; at a third surgery, within 2 to 4 weeks, the colostomy is taken down and normal integrity
1164
FREEMAN & MeN ALLY
of the bowel is restored. The three-stage approach was the standard approach for much of the 20th century but large reviews 13, 17 published in the past two decades have convincingly established the superiority of the two-stage procedure involving early resection of the involved segment. Mortality from the three-stage approach ranges from 12% to 32% whereas mortality for the two-stage procedure ranges from 1% to 12%?' 17 The two-stage procedure is presently considered to be the procedure of choice for treatment of perforated diverticulitis. Special Considerations
Management of fistulous complications of diverticulosis is a management problem with which clinicians occasionally are faced. The most common fistulous complication is the colo-urinary bladder or colovesical fistula, making up two thirds of all such complications.64 Other types of fistulae, in order of decreasing frequency are colocutaneous fistula, colovaginal fistula, and coloenteric fistula. 14 Colovesical fistula occurs with much greater frequency in men than women. The reasons for this surprising difference are unclear but the presence of a uterus in the female may offer some protection to the bladder. Miller36 pointed out that 61% of colovesical fistulas in women occurred in women who had undergone a hysterectomy. These fistulas are diagnosed by symptoms of recurrent urinary infections, fecaluria, and occasionally pneumaturia. Demonstration of the fistula can be difficult and the means of diagnosis were discussed earlier in this article. It is generally held that a well-documented colovesical fistula should be treated with surgery. Occasionally, in the high risk patient who is tolerating the condition with minimal symptoms, the condition can be treated nonsurgically.35 Surgery can be performed as a one-stage procedure in 90% of patients with very low mortality.46 Colovaginal fistulas and colocutaneous fistulas are also commonly treated with surgery with good success and low mortality but some surgeons find that these fistulae often will close with conservative medical management. 35 Those coloenteral fistulas which are sufficiently symptomatic to require surgery can usually be performed as a one-stage procedure with an en-block resection of the involved segment of the colon and small intestine. 46 CONCLUSIONS
While the majority of elderly Americans have diverticulosis, fortunately a small minority suffer the complication of diverticulitis. Most patients with this disease are able to be successfully treated medically by means of antibiotics and bowel rest, perhaps to include percutaneous catheter drainage of localized abscess. Some patients, however, are ill enough that surgical therapy is required that may be accomplished in a
DIVERTICULITIS
1165
single stage or require up to three separate procedures. Interesting new information regarding this well-known disease have been discussed: inflammatory bowel disease-like extraintestinal manifestations such as pyoderma gangrenosum and arthritis are now reported to be associated with diverticulitis; the association of unexplained back or leg pain and fever may suggest a retroperitoneal perforation and abscess from diverticulitis; not only corti co steroids, but NSAIDs may place a patient at higher risk for diverticulitis and its complications. Diverticulitis is a disease well known to clinicians which still demands understanding and careful good judgement for good patient outcome. The disease continues to offer challenging problems for the internist as well as the surgeon. References 1. Abramson ST, Berdon WE, Laffey K, et al: Colonic diverticulosis in young patients with chronic renal failure and transplantation. Pediatr Radiol 21:352-354, 1991 2. Adachi A, Gold M: Vaginography for enterovaginal fistulae. Am J Obst Gynecol 131:227-228,1978 3. Adams DB, Perry TG: Tandem colovaginoscopy in the diagnosis of colovaginal fistula. Dis Colon Rectum 31:653-654, 1988 4. Almy TP, Howell DA: Medical progress: Diverticular disease of the colon. N Engl J Med 302:324-331, 1980 5. Arsura EL: Corticosteroid-associated perforation of colonic diverticula. Arch Intern Med 150:1337-1338, 1990 6. Balthazar El, Megibow A, Schinella RA, et al: Limitations in the CT diagnosis of acute diverticulitis: Comparison of CT, contrast enema, and pathologic findings in 16 patients. Am J RoentgenoI154:281-285, 1990 7. Bohrer SP, Lewis EA: Diverticula of the colon in Ibadan. Nigeria. Trop Geogr Med 26:9-14,1974 8. Campbell K, Steele RJC: Non-steroidal anti-inflammatory drugs and complicated diverticular disease: A case-controled study. Br J Surg 78:190-191, 1991 9. Chappuis CW, Cohn I Jr: Acute colonic diverticulitis. Surg Clin North Am 68:301-313, 1988 10. Chia JG, Wilde Cc, Ngoi SS, et al: Trends in diverticular disease of the large bowel in a newly developed country. Dis Colon Rectum 34:498-501,1991 11. Cho KC, Morehouse HT, Alterman DD, et al: SigmOid diverticulitis: Diagnostic role of CT-comparison with barium enema studies. Radiology 176:111-115, 1990 12. Coder A: Steroids, non-steroidal anti-inflammatory drugs and serious complications of diverticular disease. Br Med J 295:1238, 1987 13. Eng K, Ranson JH, Localeo GA: Resection of the perforated segment: A significant advance in the treatment of diverticulitis with free perforation of abscess. Am J Surg 133:67-72, 1977 14. Fazio VW, Church JM, Jagelman DG, et al: Colocutaneous fistulas complicating diverticulitis. Dis Colon Rectum 30:89, 1987 15. Galbraith P, Bagg MN, Schabel SI, et al: Diverticular complications of renal disease. Gastrointest RadioI15:259-262, 1990 16. Greenall Ml, Levine AW, Nolan DT: Complications of diverticular disease: A review of the barium enema findings. Gastrointest RadioI8:353-358, 1983 17. Greif JM, Fried G, McSherry CK: Surgical treatment of perforated diverticulitis of the Sigmoid colon. Dis Colon Rectum 23:483-487, 1980 18. Grisson R, Snyder TE: Colovaginal fistula secondary to diverticular disease. Dis Colon Rectum 34:1043-1049,1991 19. Hafner CD, Ponka LL Brush BE: Genitourinary manifestations of diverticulitis of the colon: A study of 500 cases. JAMA 179:76, 1962
1166
FREEMAN & MeN ALL Y
20. Haiart DC, Stevenson P, Hartley RC: Leg pain: An uncommon presentation of perforated diverticular disease. J R Coll Surg Edinb 34:17-20, 1989 21. Hannan CE, Knightly JJ, Coffey RJ: Diverticular disease of the colon in the younger age group. Dis Colon Rectum 4:419-423,1961 22. Hiltuten KM, Kolehmainen H, Vuorinen T, et al: Early water-soluble contrast enema in the diagnosis of acute colonic diverticulitis. Intern J Colorect Dis 6:190-192, 1991 23. Horner JL: Natural history of diverticulosis of the colon. Am J Dig Dis 5:343-350,1958 24. Hulnick DH, Megibow AI, Balthazar EJ, et al: Computerized tomography in the evaluation of diverticulitis. Ann Surg 204:128-132,1984 25. Ihekwaba FN: Diverticular disease in black Africa. J R Coll Surg Edinb 37:107-109,1992 26. Johnson CD, Baker ME, Rice RP, et al: Diagnosis of acute colonic diverticulitis: Comparison of barium enema to CT. Am J RoentgenoI148:541-546, 1987 27. Kellum JM, Sugerman HJ: Randomized, prospective comparison of cefoxitin and gentamicin-clindamycin in the treatment of acute colonic diverticulosis. Clin Ther 14:376384, 1992 28. Klein S, Mayer L, Present DH, et al: Extraintestinal manifestations in patients with diverticulitis. Ann Intern Med 108:700-702, 1988 29. Markham NI, Li AKC: Diverticulosis of the right colon-experience from Hong Kong. Gut 33:547-549,1992 30. Marshak RH: Granulomatous colitis in association with diverticula. N Engl J Med 285:1080, 1970 31. McConnell DB, Sasaki TM, Vetto RM: Experience with colovesical fistula. Am J Surg 140:80,1980 32. Mendeloff AI: A critique of "fiber defiency." Am J Dig Dis 21:109-112,1976 33. Mendeloff AI: Dietary fiber and gastrointestinal diseases. Med Clin North Am 62:165171,1978 34. Mendeloff AI: Thoughts on the epidemiology of diverticular disease. Clin Gastroenterol 15:855-877,1986 35. Milesa WJ, Joehl RI, Rege RV, et al: One stage resection and anastomosis in the management of colovesical fistula. Am J Surg 153:75, 1987 36. Miller RE: Role of hysterectomy in predisposing the patient to sigmoidovesical fistula complicating diverticulitis. Am J Surg 147:660, 1984 37. Morris J, Stellato JA, Haaga JR, et al: The utility of computerized tomography in colonic diverticulitis. Ann Surg 204:128-132,1986 38. Omojola MF, Mangete E: Diverticula of the colon in three Nigerian siblings. Trop Geogr Med 10:45-57, 1988 39. Ouriel K, Schwartz SI: Diverticular disease in the young patient. Surg Gynecol Obstet 156:1-5,1983 40. Painter NS: Diverticular disease of the colon. Br Med J 3:475-479,1968 41. Painter NS, Burkitt DP: Diverticular disease of the colon: A deficiency disease of western civilization. Br Med J 2:450-454, 1971 42. Painter NS, Truelove SC: The intraluminal pressure patterns in diverticulosis of the colon: Resting pattern of pressure. Gut 5:201-203,1964 43. Parks TG: Natural history of diverticular disease of the colon. Clin Gastroenterol 4:53, 1975 44. Parks TG: Natural history of diverticular disease of the colon. A review of 521 cases. Br Med J 4:693, 1969 45. Parks TG: Post-mortum studies on the colon with special reference to diverticular disease. Proc R Soc Med 61:932-934,1968 46. Reve RV, Nahrwold DL: Diverticular disease. Curr Prob Surg 26:136, 1989 47. Rosen AM, Fleischer DE: Lower GI bleeding: Updated diagnosis and management. Geriatrics 44:49-60, 1989 48. Ryan P: Two kinds of diverticular disease. Ann R Coll Surg Engl 73:73-79, 1991 49. Scheff RT, Zuckerman G, Harter H, et al: Diverticular disease in patients with chronic renal failure due to polycystic kidney disease. Ann Intern Med 92:202-204, 1980 50. Scully RE, Mark El, McNeely WF, et al: Case records of the Massachusetts General Hospital. N Engl J Med 327:40-44,1992 51. Sikirov BA: Etiology and pathogenesis of diverticulosis coli: A new approach. Medical Hypothesis 26:17-20, 1988
DIVERTICULITIS
1167
52. Smith TR, Cho Ke, Morehouse HT, et al: Comparison of computed tomography and contrast enema evaluation of diverticulitis. Dis Colon Rectum 33:1-6,1990 53. Stabile BE, Puccio E, vanSonnenberg E, et al: Preoperative percutaneous drainage of diverticular abscess. Am J Surg 159:99-111, 1990 54. Sugihara K, Muto T, Morioka Y, et al: Diverticular disease of the colon in Japan: A review of 615 cases. Dis Colon Rectum 27:531,1984 55. Terry JH: Unusual cases of perforated diverticulitis of colon. J Fla Med Assoc 77:814816, 1990 56. Toombs JP, Caywood DD, Lipowitz AJ, et al: Colonic perforation following neurosurgical procedures and corticosteroid therapy in four dogs. J Am Vet Med Assoc 177:6872, 1980 57. Tranaeus A, Heimburger 0, Granqvist S: Diverticular disease of the colon: A risk factor for peritonitis in continuous peritoneal dialysis. Nephrol Dial Transplant 5:141-147, 1990 58. Vajrabukka T, Saksornchai K, Jimakorn P: Diverticular disease of the colon in a far eastern community. Dis Colon Rectum 23:151, 1980 59. Verbanck I, Lambrecht 5, Ruteerts L, et al: Can sonography diagnose acute colonic diverticulitis in patients with acute intestinal inflammation? A prospective study. J Clin Ultrasound 17:661-666, 1989 60. Wehmann TW, Rongaus VA: Diverticular disease in young adults. J Am Osteopath Assoc 89:791-793, 1989 61. Weinrich I, Anderson D: Intraluminal pressure in the sigmoid colon. Patients with sigmoid diverticular and related conditions. Scand J GastroenteroI1l:581-586, 1976 62. Wilson SR, Toi A: The value of sonography in the diagnosis of acute diverticulitis of the colon. Am J RoentgenoI154:1199-1202, 1990 63. Wolf AV: Demonstration concerning pressure - tension relations in various organs. Science 115:243-244, 1952 64. Woods RI, Lavery le, Fazio VW, et al: Internal fistulas in diverticular disease. Dis Colon Rectum 31:591-596,1988
Address reprint requests to COL Stephen R. Freeman, MC, MD Department of Medicine Building 403-W Fitzsimons Army Medical Center Aurora, CO 80045-5001