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Acute flank pain
The Journal of Emergency Medicine, Vol 15,1vo 6. pp 85 878, 1997 Copyright 0 1Y97 Elsevier Science Inc. Printed in the USA. All rights reserved 07X6-4679/97 ‘517.00 + 00
ELSiiVIER
PII SO736-4679(97)00198-4
ACUTE FLANK PAIN David F. M. Brown, ‘Departments
of Emergency
MD,*
and Eric S. Nadel, rmt
Medicine, Massachusetts General Hospital and t Brigham & Women’s Emergency Medicine, Harvard Medical School, Boston, Massachusetts
respirations were 18 breaths/mm, and the oral temperature was 36.7”C (98.0’F). The skin was warm and moist, the head and neck were normal, the chest was clear, and heart sounds were regular with no gallops, murmurs, or rubs. The abdomenwas soft and nondistendedwith normal bowel sounds. There were no hernias, masses,or organomegaly. There was moderatetendernessto palpation in the LLQ and left flank with mild tendernessin the left epigastrium and LUQ. There was no guarding or rebound tenderness.There was mild left costovertebral angle tenderness. The rectum was nontender with no masses.The stool was negative for occult blood. The extremities had no edema; pulses were symmetric and full. Neurological examination was normal. Are there any questions regarding the physical examination? Dr. Eric S. Nadel: Was he lying still or moving about on the stretcher?Was there a rash on the left abdomenthat might suggest herpes zoster? Were there any signs of trauma? What did the genitourinary (GIJ) examination show? Dr. Brown: He was moving about as if he were trying to get comfortable on the stretcher. There were no rashes and no external signs of trauma. The GU examination revealed a normal penis, nontender testes with no epididymal tenderness,and no hernias. What laboratory or radiological tests are appropriate at this point? What is the differential diagnosis? Carlo L. Rosen: The leading diagnosis at this point is renal colic due to ureterolithiasis. I would order a urinalysis (UA), a serum BUN and creatinine, and either an i.v. pyelogram (IVP) or an unenhancedhelical computed
David F. M. Brown: Today’s caseis that of a 32-yearold man who presented to the Emergency Department (ED) complaining of left-sided abdominal and flank pain. The pain was severe, sharp, continuous, and abrupt in onset 4 h before presentation. It began at rest, was unrelated to exertion or position, and was nonpleuritic. The patient described nausea,but no vomiting, diarrhea, fever, dysuria, frequency, or hematuria. He had no significant past medical history, had no prior surgery, and was on no medications. He was a physician visiting Boston who did not smoke, had rare alcohol intake, and used no other drugs. Are there any questions regarding the history? Eric L. Legome: Was the pain more severe in the abdomen or in the flank? Was there radiation to the groin? Had he ever had symptomslike these in the past? Dr. Brown: The most severe pain was in the left flank and left lower quadrant (LLQ). There was moderate discomfort in the left upper quadrant (LUQ). There was no radiation to the groin. He had not had similar symptoms previously. Jonathan N. Adler: What was he doing when the symptoms began?Was the pain most severeat its onset?Were there any recent illnesses or trauma? Dr. Brown: He was sitting in a chair at a medical conference when the pain started. The symptoms worsenedjust before presentationbut were severethroughout. He recalled no recent illness or trauma. On physical examination, he was a well-developed man in obvious distress on a stretcher. The blood pressure was 16.5/90mmHg, the heart rate was 80 beats/mm, CasePresentationsis coordinated by David F. M. Brown, Massachusetts RECEIVED:
20 August 1997; ACCEPTED
Hospital, and Division of
20 August 1997 875
MD,
and Eric S. Nadel,
MD
of Harvard Medical School, Boston,
876
tomography (CT) scan.A formal renal ultrasound (US) is also an imaging option, but although very sensitive for detecting hydronephrosis, renal US is less accurate in identifying the calculus than IVP or CT scan (l-5). In our facility, we are utilizing helical CT scan rather than IVP to diagnose suspectedrenal colic. Unenhanced helical CT is at least as accurate as IVP in identifying the stone in the GU tract, even when in the bladder, allows for sizing of the stone, is more rapidly performed, does not require administration of i.v. contrast, and provides additional information about other structures in the abdominal cavity (6,7). Dr. Nadel: I agree that ureterolitbiasis is most likely here. The other possible diagnosesthat might account for the sudden onset of symptoms are vascular in origin, specifically aortic dissection with compromise of circulation to the bowel or the left kidney, splenic or left renal vein thrombosis, or an embolus to the left renal artery or the mesenteric circulation. If the UA is negative for hematuria, I would check the blood pressures in both arms and order an electrocardiogram (ECG) to rule out atrial fibrillation as a possible cause of systemic embolization. Dr. Brown: The BUN was 10 mg/dL, the creatinine was 1.1 mg/dL, and the urinalysis was negative for red blood cells with three to five white blood cells/high-powered field and was otherwise unremarkable.The ECG showed normal sinus rhythm with no ischemia. A complete blood count (CBC) revealed a white blood cell (WBC) count of 10.9 K/mm3, a hematocrit of 46%, and a normal platelet count. An unenhancedhelical CT scan was ordered. Ron M. Walls: A CBC at this point in the patient’s evaluation is of no value. There is no reason to suspect anemia or thrombocytopenia and the WBC count is of no diagnostic or prognostic value. The absenceof hematuria in this patient does not exclude the possibility of ureterolithiasis. Five to ten percent of patients with urolithiasis will present without microscopic hematuria, and this is still the leading diagnosis (8). Uncommon presentations of common illnesses are more likely than rare illnesses.In this vein, the ECG could probably have been deferred unless the helical CT scan was negative. Did you perform a bedside US examination yourself to screen for hydronephrosis? Dr. Brown: A bedside emergency US was performed and was negative for signs of hydronephrosis. In addition, no free intraperitoneal fluid was noted on US. We have presenteddata at SAEM that suggestthat in patients with suspectedureterolithiasis, if the UA is negative for microscopic hematuria and the bedsideUS performed by the emergencyphysician does not show hydronephrosis, the likelihood of finding urolithiasis on subsequentimaging study is exceedingly small, approaching 0% (9). Nonetheless, we proceededwith an unenhanced helical
D. F. M. Brown and E. S. Nadel
Figure 1. Unenhanced helical CT scan shows pearing kidneys with no evidence of urolithiasis.
normal-ap-
CT scan,which was negative for urolithiasis and did not show any other abnormalities (Figure 1). Are there any comments at this point? A Resident: Did the patient receive pain medication before the CT scan? If so, was surgical consultation obtained before the administration of analgesia? Dr. Brown: He received 5 mg of i.v. morphine in divided doses and 30 mg of iv. ketorolac before the CT scan. A surgical consultation had not been obtained at this point. Dr. Walls: This raises an important issue regarding the administration of opioid analgesia to patients with abdominal pain. The classical teaching hasbeen that opioid analgesia may mask progression of findings including peritonitis and therefore should not be administered to thesepatients. This datesback to the teaching of Zachary Cope in his classic book, Early Diagnosis of the Acute Abdomen, first published in 1921.Over the past 25 years, this teaching has been modified to allow for administration of opioid analgesiaonly after a surgical consultation, and this is still the teaching of ATLS. However, it has become clear from several carefully performed studies during the past decade that the administration of judicious dosesof parenteral narcotics to patients with acute abdominal pain does not alter the physical findings necessary for accurate diagnosis (10-12). I believe opioid administration facilitates diagnosis, as the patient can cooperatemore easily with the history, physical examination, and any ancillary studies. Furthermore, some patients who clearly need opioid analgesiamay not ultimately require surgical consultation, such as a patient with pain from ureterolithiasis. To withhold analgesiain patients with abdominal pain while awaiting a surgical consultation or other procedure or test is medically and ethically inappropriate.
Acute Flank Pain
a77
Figure 2. Repeat CT scan with oral and i.v. contrast same level as used in Fiiure 1 reveals wedge-shaped in the posterolateral segment of the left kidney.
at the infarct
Richard E. Wolfe: So at this point, you had a patient with a normal UA and a normal unenhanced helical abdominal CT scan who still was in acute distress with left sided flank and abdominal pain. You did not obtain a chest radiograph, but the abdominal CT scan would have picked up an occult pneumothorax, which is part of the differential diagnosis. I am now most concerned about an intra-abdominal vascular event, specifically an aortic dissection or perhaps a splenic or renal vein thrombosis or arterial embolus. A pulmonary embolus is also
Figure 3. Coronal
reformation
of contrast-enhanced
possible, although the presentation is quite atypical. What did the repeat abdominal examination reveal? Dr. Brown: He was still uncomfortabie and complaining of left flank and left abdominal pain. He had vomited once without hematemesis. The repeat abdominal examination revealed persistent tenderness in the left flank and left mid-abdomen with no findings of peritoneal irritation. A pulmonary embolus was considered very unlikely, as the pain was abdominal and nonpleuritic, there was no associated dyspnea, he was not tachypneic or tachycardic, and his oxygen saturation was 100% without supplemental oxygen. We were also worried about a vascular problem involving the left kidney, the spleen, or the gastrointestinal tract now that urolithiasis had been excluded. Are there any thoughts on how to proceed? Dr. Rosen: Your options at this point are to proceed with contrast angiography, contrast enhanced CT scan. or Doppler US of the abdomen. The US is least invasive and avoids contrast administration, but will give only limited information about blood flow in the renal and splenic arteries and veins. Unless venous thrombosis is at the top of your differential, I would not choose this imaging option. Contrast administration really should not be an issue in this otherwise healthy young man with a normal creatinine. Angiography is most invasive, but is the gold standard test for aortic dissection. In this case, with the CT scan immediately available, I would proceed with an i,\t. contrast-enhanced CT scan of the abdomen.
CT scan shows
posterolateral
infarct
of the left kidney.
878
D. F. M. Brown and E. S. Nadel
Dr. Brown: This is the logic we followed as well. We were more concernedwith an arterial problem than with venous thrombosis, as the patient had no evidence of trauma, malignancy, or nephrotic syndrome, all of which are risk factors for venous thrombosis. He went for a repeat CT scan of the abdomen with oral and i.v. contrast. Before this he received a parenteral antiemetic and an additional dose of a parenteral opioid analgesic. The CT scanrevealed a wedge-shapedperfusion defect of the left kidney (Figures 2 and 3). No abnormality was noted in the abdominal aorta or in the splenic and renal arteries and veins. He was diagnosedwith a left renal segmental infarction secondary to an embolus and was started on i.v. heparin. Admission to the hospital was recommended,but he preferred to return to his own hospital in New York for further evaluation and left against medical advice. Renal embolus is an uncommon but important cause of flank pain that mimics the clinical presentation of acute ureterolithiasis. Risk factors include atrial fibrillation, valvular heart disease,infective endocarditis, cardiac mural thrombi, and ulcerating atherosclerosisof the aorta. Although small infarcts may be clinically silent, larger infarcts present with acute unremitting flank or abdominal pain usually associatedwith gross or microscopic hematuria, leukocytosis, and fever. For small seg-
mental infarcts such as this one, there is generally no long-term effect on renal function, and treatmentconsists of a period of anticoagulation and managementof the underlying cause of embolization. Bilateral emboli or a larger single embolus causing total or near-total truncal occlusion of the renal artery require more aggressive treatment with surgical embolectomy or fibrinolytic therapy (13,141. Mark Davis: Did you consider sending him out on low molecular weight heparin, which would provide longer lasting anticoagulation than standard heparin while he returned to New York? Dr. Brown: We did not consider this, but I think it is a very good suggestion. The patient underwent an extensive negative evaluation in New York for a source of embolus. Holter monitoring revealed no evidence of paroxysmal atrial fibrillation. A cardiac US demonstrated normal valves with no vegetations and no mural thrombus; a bubble study was negative for a patent foramen ovale. Lower extremity venous Doppler US was negative for deep venous thrombosis. An aortogram and renal angiogram were negative except for the segmental left renal infarction. Work-up for a hypercoagulable state was entirely negative as well, as was hemoglobin electrophoresis. At present, he is doing well on warfarin anticoagulation and has returned to work.
REFERENCES 1. Sinclair D, Wilson S, Toi A, et al. The evaluation of suspected renal colic: ultrasound scan versus excretory urography. Ann Emerg Med. 1989;18:556-9. 2. Saita H, Matsukawa M, Fukushima H, et al. Ultrasound diagnosis of ureteral stones:its usefulnesswith subsequentexcretory urography. J Urol. 1988;140:28-31. 3. Erwin BC, Carroll BA, Sommer FG. Renal colic: the role of ultrasound in initial evaluation. Radiology. 1984;152: 147-50. 4. Hill MC, Rich JI, Mardiat JG, et al. Sonography vs. excretory urography in acute flank pain. Am J Roentgenol. 1985;144: 1235-8. 5. Svedstrom E, Alanen A, Nurmi M. Radiologic diagnosis of renal colic: the role of plain films, excretory urography and sonography. Em J Radio]. 1990;11:180-3. 6. Smith RC, Rosenfield AT, Choe KA, et al. Acute flank pain: comparison of noncontrast-enhancedCT and intravenous urography. Radiology. 1985;194:789-94. 7. Smith RC, Verga M, McCarthy S, et al. Diagnosis of acute flank
pain: value of unenhancedhelical CT. Am J Roentgenol. 1996; 166:97-101. 8. PressSM, Smith AD. Incidence of negative hematuria in patients with acute urinary lithiasis presenting to the emergencyroom with flank pain. Urology. 1995;45:753-7. 9. Brown DFM, Rosen CL, Chang YC, et al. Efficacy of a clinical pathway for suspectedureteral colic in reducing IV pyelogram utilization. Acad Emerg Med. 1996,3:482.Abstract. 10. Zoltie N, Cust MP. Analgesia in the acute abdomen.Ann R Co11 Surg Engl. 1986;68:209-10. 11. Attard AR, Corlett MJ, Kidner NJ, et al. Safety of early pain relief for acute abdominal pain. Br Med J. 1992;305:554-6. 12. Pace S, Burke TF. Intravenous morphine for early pain relief in patients with acute abdominal pain. Acad Emerg Med. 1994;3: 1086-92. 13. Walters BL, GrunauCF, ParmanSC. Renal artery obstruction.Ann Emerg Med. 1985;14:607-10. 14. Bouttier S, Valverde JP, Lacombe M, et al. Renal artery emboli: the role of surgical management.Ann Vast Surg. 1988;2:161-8.
ELSiiVIER
PII SO736-4679(97)00198-4
ACUTE FLANK PAIN David F. M. Brown, ‘Departments
of Emergency
MD,*
and Eric S. Nadel, rmt
Medicine, Massachusetts General Hospital and t Brigham & Women’s Emergency Medicine, Harvard Medical School, Boston, Massachusetts
respirations were 18 breaths/mm, and the oral temperature was 36.7”C (98.0’F). The skin was warm and moist, the head and neck were normal, the chest was clear, and heart sounds were regular with no gallops, murmurs, or rubs. The abdomenwas soft and nondistendedwith normal bowel sounds. There were no hernias, masses,or organomegaly. There was moderatetendernessto palpation in the LLQ and left flank with mild tendernessin the left epigastrium and LUQ. There was no guarding or rebound tenderness.There was mild left costovertebral angle tenderness. The rectum was nontender with no masses.The stool was negative for occult blood. The extremities had no edema; pulses were symmetric and full. Neurological examination was normal. Are there any questions regarding the physical examination? Dr. Eric S. Nadel: Was he lying still or moving about on the stretcher?Was there a rash on the left abdomenthat might suggest herpes zoster? Were there any signs of trauma? What did the genitourinary (GIJ) examination show? Dr. Brown: He was moving about as if he were trying to get comfortable on the stretcher. There were no rashes and no external signs of trauma. The GU examination revealed a normal penis, nontender testes with no epididymal tenderness,and no hernias. What laboratory or radiological tests are appropriate at this point? What is the differential diagnosis? Carlo L. Rosen: The leading diagnosis at this point is renal colic due to ureterolithiasis. I would order a urinalysis (UA), a serum BUN and creatinine, and either an i.v. pyelogram (IVP) or an unenhancedhelical computed
David F. M. Brown: Today’s caseis that of a 32-yearold man who presented to the Emergency Department (ED) complaining of left-sided abdominal and flank pain. The pain was severe, sharp, continuous, and abrupt in onset 4 h before presentation. It began at rest, was unrelated to exertion or position, and was nonpleuritic. The patient described nausea,but no vomiting, diarrhea, fever, dysuria, frequency, or hematuria. He had no significant past medical history, had no prior surgery, and was on no medications. He was a physician visiting Boston who did not smoke, had rare alcohol intake, and used no other drugs. Are there any questions regarding the history? Eric L. Legome: Was the pain more severe in the abdomen or in the flank? Was there radiation to the groin? Had he ever had symptomslike these in the past? Dr. Brown: The most severe pain was in the left flank and left lower quadrant (LLQ). There was moderate discomfort in the left upper quadrant (LUQ). There was no radiation to the groin. He had not had similar symptoms previously. Jonathan N. Adler: What was he doing when the symptoms began?Was the pain most severeat its onset?Were there any recent illnesses or trauma? Dr. Brown: He was sitting in a chair at a medical conference when the pain started. The symptoms worsenedjust before presentationbut were severethroughout. He recalled no recent illness or trauma. On physical examination, he was a well-developed man in obvious distress on a stretcher. The blood pressure was 16.5/90mmHg, the heart rate was 80 beats/mm, CasePresentationsis coordinated by David F. M. Brown, Massachusetts RECEIVED:
20 August 1997; ACCEPTED
Hospital, and Division of
20 August 1997 875
MD,
and Eric S. Nadel,
MD
of Harvard Medical School, Boston,
876
tomography (CT) scan.A formal renal ultrasound (US) is also an imaging option, but although very sensitive for detecting hydronephrosis, renal US is less accurate in identifying the calculus than IVP or CT scan (l-5). In our facility, we are utilizing helical CT scan rather than IVP to diagnose suspectedrenal colic. Unenhanced helical CT is at least as accurate as IVP in identifying the stone in the GU tract, even when in the bladder, allows for sizing of the stone, is more rapidly performed, does not require administration of i.v. contrast, and provides additional information about other structures in the abdominal cavity (6,7). Dr. Nadel: I agree that ureterolitbiasis is most likely here. The other possible diagnosesthat might account for the sudden onset of symptoms are vascular in origin, specifically aortic dissection with compromise of circulation to the bowel or the left kidney, splenic or left renal vein thrombosis, or an embolus to the left renal artery or the mesenteric circulation. If the UA is negative for hematuria, I would check the blood pressures in both arms and order an electrocardiogram (ECG) to rule out atrial fibrillation as a possible cause of systemic embolization. Dr. Brown: The BUN was 10 mg/dL, the creatinine was 1.1 mg/dL, and the urinalysis was negative for red blood cells with three to five white blood cells/high-powered field and was otherwise unremarkable.The ECG showed normal sinus rhythm with no ischemia. A complete blood count (CBC) revealed a white blood cell (WBC) count of 10.9 K/mm3, a hematocrit of 46%, and a normal platelet count. An unenhancedhelical CT scan was ordered. Ron M. Walls: A CBC at this point in the patient’s evaluation is of no value. There is no reason to suspect anemia or thrombocytopenia and the WBC count is of no diagnostic or prognostic value. The absenceof hematuria in this patient does not exclude the possibility of ureterolithiasis. Five to ten percent of patients with urolithiasis will present without microscopic hematuria, and this is still the leading diagnosis (8). Uncommon presentations of common illnesses are more likely than rare illnesses.In this vein, the ECG could probably have been deferred unless the helical CT scan was negative. Did you perform a bedside US examination yourself to screen for hydronephrosis? Dr. Brown: A bedside emergency US was performed and was negative for signs of hydronephrosis. In addition, no free intraperitoneal fluid was noted on US. We have presenteddata at SAEM that suggestthat in patients with suspectedureterolithiasis, if the UA is negative for microscopic hematuria and the bedsideUS performed by the emergencyphysician does not show hydronephrosis, the likelihood of finding urolithiasis on subsequentimaging study is exceedingly small, approaching 0% (9). Nonetheless, we proceededwith an unenhanced helical
D. F. M. Brown and E. S. Nadel
Figure 1. Unenhanced helical CT scan shows pearing kidneys with no evidence of urolithiasis.
normal-ap-
CT scan,which was negative for urolithiasis and did not show any other abnormalities (Figure 1). Are there any comments at this point? A Resident: Did the patient receive pain medication before the CT scan? If so, was surgical consultation obtained before the administration of analgesia? Dr. Brown: He received 5 mg of i.v. morphine in divided doses and 30 mg of iv. ketorolac before the CT scan. A surgical consultation had not been obtained at this point. Dr. Walls: This raises an important issue regarding the administration of opioid analgesia to patients with abdominal pain. The classical teaching hasbeen that opioid analgesia may mask progression of findings including peritonitis and therefore should not be administered to thesepatients. This datesback to the teaching of Zachary Cope in his classic book, Early Diagnosis of the Acute Abdomen, first published in 1921.Over the past 25 years, this teaching has been modified to allow for administration of opioid analgesiaonly after a surgical consultation, and this is still the teaching of ATLS. However, it has become clear from several carefully performed studies during the past decade that the administration of judicious dosesof parenteral narcotics to patients with acute abdominal pain does not alter the physical findings necessary for accurate diagnosis (10-12). I believe opioid administration facilitates diagnosis, as the patient can cooperatemore easily with the history, physical examination, and any ancillary studies. Furthermore, some patients who clearly need opioid analgesiamay not ultimately require surgical consultation, such as a patient with pain from ureterolithiasis. To withhold analgesiain patients with abdominal pain while awaiting a surgical consultation or other procedure or test is medically and ethically inappropriate.
Acute Flank Pain
a77
Figure 2. Repeat CT scan with oral and i.v. contrast same level as used in Fiiure 1 reveals wedge-shaped in the posterolateral segment of the left kidney.
at the infarct
Richard E. Wolfe: So at this point, you had a patient with a normal UA and a normal unenhanced helical abdominal CT scan who still was in acute distress with left sided flank and abdominal pain. You did not obtain a chest radiograph, but the abdominal CT scan would have picked up an occult pneumothorax, which is part of the differential diagnosis. I am now most concerned about an intra-abdominal vascular event, specifically an aortic dissection or perhaps a splenic or renal vein thrombosis or arterial embolus. A pulmonary embolus is also
Figure 3. Coronal
reformation
of contrast-enhanced
possible, although the presentation is quite atypical. What did the repeat abdominal examination reveal? Dr. Brown: He was still uncomfortabie and complaining of left flank and left abdominal pain. He had vomited once without hematemesis. The repeat abdominal examination revealed persistent tenderness in the left flank and left mid-abdomen with no findings of peritoneal irritation. A pulmonary embolus was considered very unlikely, as the pain was abdominal and nonpleuritic, there was no associated dyspnea, he was not tachypneic or tachycardic, and his oxygen saturation was 100% without supplemental oxygen. We were also worried about a vascular problem involving the left kidney, the spleen, or the gastrointestinal tract now that urolithiasis had been excluded. Are there any thoughts on how to proceed? Dr. Rosen: Your options at this point are to proceed with contrast angiography, contrast enhanced CT scan. or Doppler US of the abdomen. The US is least invasive and avoids contrast administration, but will give only limited information about blood flow in the renal and splenic arteries and veins. Unless venous thrombosis is at the top of your differential, I would not choose this imaging option. Contrast administration really should not be an issue in this otherwise healthy young man with a normal creatinine. Angiography is most invasive, but is the gold standard test for aortic dissection. In this case, with the CT scan immediately available, I would proceed with an i,\t. contrast-enhanced CT scan of the abdomen.
CT scan shows
posterolateral
infarct
of the left kidney.
878
D. F. M. Brown and E. S. Nadel
Dr. Brown: This is the logic we followed as well. We were more concernedwith an arterial problem than with venous thrombosis, as the patient had no evidence of trauma, malignancy, or nephrotic syndrome, all of which are risk factors for venous thrombosis. He went for a repeat CT scan of the abdomen with oral and i.v. contrast. Before this he received a parenteral antiemetic and an additional dose of a parenteral opioid analgesic. The CT scanrevealed a wedge-shapedperfusion defect of the left kidney (Figures 2 and 3). No abnormality was noted in the abdominal aorta or in the splenic and renal arteries and veins. He was diagnosedwith a left renal segmental infarction secondary to an embolus and was started on i.v. heparin. Admission to the hospital was recommended,but he preferred to return to his own hospital in New York for further evaluation and left against medical advice. Renal embolus is an uncommon but important cause of flank pain that mimics the clinical presentation of acute ureterolithiasis. Risk factors include atrial fibrillation, valvular heart disease,infective endocarditis, cardiac mural thrombi, and ulcerating atherosclerosisof the aorta. Although small infarcts may be clinically silent, larger infarcts present with acute unremitting flank or abdominal pain usually associatedwith gross or microscopic hematuria, leukocytosis, and fever. For small seg-
mental infarcts such as this one, there is generally no long-term effect on renal function, and treatmentconsists of a period of anticoagulation and managementof the underlying cause of embolization. Bilateral emboli or a larger single embolus causing total or near-total truncal occlusion of the renal artery require more aggressive treatment with surgical embolectomy or fibrinolytic therapy (13,141. Mark Davis: Did you consider sending him out on low molecular weight heparin, which would provide longer lasting anticoagulation than standard heparin while he returned to New York? Dr. Brown: We did not consider this, but I think it is a very good suggestion. The patient underwent an extensive negative evaluation in New York for a source of embolus. Holter monitoring revealed no evidence of paroxysmal atrial fibrillation. A cardiac US demonstrated normal valves with no vegetations and no mural thrombus; a bubble study was negative for a patent foramen ovale. Lower extremity venous Doppler US was negative for deep venous thrombosis. An aortogram and renal angiogram were negative except for the segmental left renal infarction. Work-up for a hypercoagulable state was entirely negative as well, as was hemoglobin electrophoresis. At present, he is doing well on warfarin anticoagulation and has returned to work.
REFERENCES 1. Sinclair D, Wilson S, Toi A, et al. The evaluation of suspected renal colic: ultrasound scan versus excretory urography. Ann Emerg Med. 1989;18:556-9. 2. Saita H, Matsukawa M, Fukushima H, et al. Ultrasound diagnosis of ureteral stones:its usefulnesswith subsequentexcretory urography. J Urol. 1988;140:28-31. 3. Erwin BC, Carroll BA, Sommer FG. Renal colic: the role of ultrasound in initial evaluation. Radiology. 1984;152: 147-50. 4. Hill MC, Rich JI, Mardiat JG, et al. Sonography vs. excretory urography in acute flank pain. Am J Roentgenol. 1985;144: 1235-8. 5. Svedstrom E, Alanen A, Nurmi M. Radiologic diagnosis of renal colic: the role of plain films, excretory urography and sonography. Em J Radio]. 1990;11:180-3. 6. Smith RC, Rosenfield AT, Choe KA, et al. Acute flank pain: comparison of noncontrast-enhancedCT and intravenous urography. Radiology. 1985;194:789-94. 7. Smith RC, Verga M, McCarthy S, et al. Diagnosis of acute flank
pain: value of unenhancedhelical CT. Am J Roentgenol. 1996; 166:97-101. 8. PressSM, Smith AD. Incidence of negative hematuria in patients with acute urinary lithiasis presenting to the emergencyroom with flank pain. Urology. 1995;45:753-7. 9. Brown DFM, Rosen CL, Chang YC, et al. Efficacy of a clinical pathway for suspectedureteral colic in reducing IV pyelogram utilization. Acad Emerg Med. 1996,3:482.Abstract. 10. Zoltie N, Cust MP. Analgesia in the acute abdomen.Ann R Co11 Surg Engl. 1986;68:209-10. 11. Attard AR, Corlett MJ, Kidner NJ, et al. Safety of early pain relief for acute abdominal pain. Br Med J. 1992;305:554-6. 12. Pace S, Burke TF. Intravenous morphine for early pain relief in patients with acute abdominal pain. Acad Emerg Med. 1994;3: 1086-92. 13. Walters BL, GrunauCF, ParmanSC. Renal artery obstruction.Ann Emerg Med. 1985;14:607-10. 14. Bouttier S, Valverde JP, Lacombe M, et al. Renal artery emboli: the role of surgical management.Ann Vast Surg. 1988;2:161-8.