• ' . Aortic dissection in acute pancreatitis CDR WALTER B. GOFF II, Me, USN CDR DAVID p, LAWRENCE, Me, USN CDR THOMAS K. BURKHARD, Me, USN Extrapancreatic fl~id collec­ sect the wall of the abdominal aorta. This is tions are frequently seen in acute pancre­ the first known case of this kind documented atitis. Vascular damage with life-threaten­ with computed tomography (CT). ing hemorrhage is also a known compli­ cation. In the case report presented, we Report of case include documentation by computed to­ A 54-year-old man was hospitalized with severe mography of an apparent abdominal right upper quadrant and abdominal pain. His se­ aortic wall dissection by fluid in a patient rum amylase level was elevated to 3000 + U/dL. with acute pancreatitis. Conservative ther­ A complete blood cell count revealed normal he­ apy resulted in complete resolution with­ moglobin and hematocrit values and elevation of the white blood cell count. There was no previous out hemorrhage or aneurysm formation. history of pancreatitis; however, alcohol abuse was (Key words: Extrapancreatic fluid col­ a known contributing factor. A routine acute ab­ lection, pancreatitis, aortic dissection) dominal x-ray series revealed an ileus pattern with bilateral pleural effusions. Ultrasonography of the Acute pancreatitis is frequently accompa­ abdomen revealed gallstones, but the pancreas nied by fluid collections-either intrapan­ could not be visualized because of bowel gas. A CT creatic or extra pancreatic. 1 These fluid collec­ scan of the abdomen (Figures 1 and 2) revealed an tions are thought to be precursors of a pancre­ extrapancreatic fluid collection that appeared to atic pseudocyst. However, once the acute epi­ dissect caudally along the superior mesenteric ar­ tery into the substance of the abdominal aorta. This sode is over, many fluid collections resolve spon­ dissection extended for a distance of about 4 cm 2 taneously and cause no long-term problems. and appeared to separate the layers of the aortic Another rarer, but frequently lethal, compli~ wall. A surgical opinion was sought and it was de­ cation of pancreatitis is massive hemorrhage. cided that any invasive procedure was contraindi­ Hemorrhage may occur within the substance cated because of a high risk for aortic rupture. The of the pancreas or from damage to adjacent patient was treated conservatively with supportive blood vessels. The overall mortality rate of therapy and bed rest. A follow-up CT scan 6 weeks these complications in one large series was later showed complete resolution of the fluid col­ 52.3%.2 lection with no evidence of aneurysmal dilation. Following is a case report of an extrapan­ Discussion creatic fluid collection that appeared to dis- Fluid collections occurring during acute pan­ From the Departments ofRadiology~nd Clinical Investi­ creatitis must be distinguished from a true pseu­ gation (Commanders Goff and Burkhard), Naval Hos­ docyst. The persistence of a fluid collection be­ pital, San Diego, Calif, and the Radiology Department, Naval Hospital, Bethesda, Md (Commander Lawrence). yond the acute phase, with the development The Chief, Navy Bureau of Medicine and Surgery, ofa well-defined wall, constitutes the accepted Washington, DC, Clinical Investigation Program spon­ criterion for a pseudocyst. Because most fluid sored this care report No , 84-16-1968-198, The views ex­ collections regress as the acute pancreatitis sub­ pressed in this article are those of the authors and do not reflect the official policy or position of the Depart­ sides, a watchful, nonsurgical approach can be ment of the Navy, Department of Defense, nor the US taken in the case of the stable patient. This Government. case demonstrates that even potentially life­ Reprint requests to CDR W. B. Goff II; MC, USN, c/o Clinical Investigation Dept, Naval Hospital, San Diego, threatening complications may undergo com­ CA 92135-5000. plete resolution. Case report • Goff et al JAOA • Vol 92 • No 7 • July 1992 • 921 Figure 1. Computed tomography scan, with intravenous contrast, at the level of the superior mesenteric artery (SMA). Note the low attenuation fluid collec­ tion by the SMA (arrow). Figure 2. Computed tomography scan at a slightly lower level in which the extrapancreatic fluid collection appears to have dissected the substance of the abdominal aorta (arrow). In most cases of acute pancreatitis, the fat Formation of a pseudoaneurysm in pancreati­ surrounding the superior mesenteric artery tis has been documented by CT. It has been and the superior mesenteric vein remains un­ estimated to occur in as high as 10% of pa­ affected.3 This fact has been used in difficult tients with pancreatitis. The mortality rate is cases to differentiate between inflammatory estimated at 37%.5 In a series by Stroud and and neoplastic disease. Pancreatic neoplasia coworkers,6 the overall mortality rate in 15 more commonly affects the vascularity by in­ patients was 57% when hemorrhage compli­ vasion and obliterates the fat planes. Only an cated pancreatitis. Hemorrhage has been de­ occasional case report is found in the litera­ scribed from leaking pseudoaneurysms of the ture in which the periarterial fat is obliter­ splenic, gastroduodenal, pancreaticoduodenal, ated in acute pancreatitis.4 left gastric, and hepatic arteries. 2 922 • JAOA • Vol 92 • No 7 • July 1992 Case report • Goff et al Ligation and transcatheter em­ bolization have been the pro­ cedures of choice for these pseu­ doaneurysms.2 Additionally, hemorrhage has been de­ scribed from inflammatory tis­ sue in a cyst wall or by erosion of the duodenum or colon by pancreatic enzymes. This case also suggests that larger ves­ sels may potentially be in­ volved. With increased imaging of patients with pancreatitis, new and unusual patterns of disease are being found. Many of these complications have the potential for a poor patient outcome. However, if the pa­ tient is stable, a course of sup­ portive measures and watchful waiting may be the best ther­ apy. Figure 3. Magnified view offZuid collection and its relationship to abdomi­ nal aorta. References 1. Casolo F, Bianco R, Frencishelli N: Per­ irenal fluid collection complicating pan­ creatitis: CT demonstration, gastrointes­ tinal. Radiology 1987;12: 117 -120. 2. Siegelman SS, Fishman EK: Computed tomography of pancreatitis, in Siegelman SS (ed): Computed Tomography ofth e Pan­ creas. New York, NY, Churchill Living­ stone, 1983, pp 83-93. 3. Lee JKT, Sagel SS, Stanley RJ: Com­ puted Body Tomography, ed 2. New York, NY, Raven Press, 1989. 4. Luetmer PH, Stephens DH, Fischer AP: Obliteration of periarterial retropan­ creatic fat on CT in pancreatitis: An ex­ ception to the rule. Am J Radiol 1989;153:63-64. 5. Burke JW, Erickson SJ, Kellum CD, et al: Pseudoaneurysms complicating pan­ creatitis: Detection by CT. Radiology 1986;161:447-450. Figure 4. S econd contrast computed tomography scan at the same level as 6. Stroud WH, Collom JW, Anderson MC : Figure 2, six weeks later. There has bee n complete resolution of the aortic Hemorrhagic complications of severe pan­ dissection with no residual aneurysm. creatitis. Surgery 1981;4:657-665. Case report • Goff et al JAOA • Vol 92 • No 7 • July 19f12 • 923 .