North Shore-Long Island Jewish Health System, New Hyde Park, New York, USA.
Received 9 April, 2009
Accepted 11 August, 2009
Address correspondence and reprint requests to Yonathan Fuchs, North Shore-Long Island Jewish Health System, 269-01 76th Avenue, New Hyde Park, NY 11040 (e-mail: firstname.lastname@example.org).
The authors report no conflicts of interest.
Splenic artery pseudoaneurysm (SAP) formation is an uncommon complication of pancreatitis. It is believed to be the result of vascular erosion by pancreatic enzymes, a process that compromises the integrity of the splenic artery wall. The final result is a weak, expanded vessel wall that may hemorrhage into the peritoneal cavity or retroperitoneal space (1). There are no known reports of SAP in the pediatric population or in patients with hereditary pancreatitis. We report a case of SAP formation in a 5-year-old child with hereditary pancreatitis that was successfully managed via transcatheter coil embolization of the splenic artery.
The patient is a 5-year-old male who was brought to medical attention in his home country of Niger, Africa, secondary to a long-standing history of poor weight gain and recurrent abdominal pain. An initial workup was remarkable for an elevated amylase and lipase, 200 and 188 μ/L, respectively. Hepatic enzymes were reported to be 2.5 times above the normal range. He was brought to our institution for further care. At presentation to our institution, the patient was found to be thin appearing (BMI <5%), but in no acute distress. He would periodically complain of severe, diffuse abdominal pain. Initial laboratory evaluation and pancreatic ultrasound confirmed the diagnosis of pancreatitis. Persistently elevated pancreatic enzymes and ongoing, at times severe, abdominal pain prompted a comprehensive evaluation for chronic pancreatitis. Genetic testing revealed 2 mutations consistent with the diagnosis of hereditary pancreatitis: an R122H mutation in the PRSS1 gene as well as a c.1-41G>A mutation in the SPINK1 gene. The patient ultimately gained weight with total parenteral nutrition and later via a low-fat elemental formula administered through a nasogastric tube. His oral intake was minimal, even on days when he was comfortable, presumably because he had developed a food aversion secondary to a long-standing association with eating and abdominal pain.
Magnetic resonance cholangiopancreatography demonstrated pancreatitis with mild dilatation of the main pancreatic duct, surrounding inflammation, and a small fluid collection at the pancreatic tail. It was believed that a strictured segment proximal to the area of dilatation may be present, potentially contributing to the patient's ongoing pancreatitis. Given this clinical picture, the decision was made to have the child undergo an endoscopic retrograde cholangiopancreatography for possible sphincterotomy or balloon dilatation followed by stent placement. The endoscopic retrograde cholangiopancreatography revealed proteinaceous material in the pancreatic duct but no gallstones. A sphincterotomy was performed and a stent was placed in the pancreatic duct. The patient was discharged to a chronic care facility where he was enrolled in a feeding therapy program while continuing to receive nasogastric tube feeds.
The patient was readmitted within 2 weeks secondary to severe abdominal pain and fever. A computed tomography scan revealed an ill-defined pancreas with heterogeneous enhancement as well as a small pseudocyst. The spleen was large and contained irregular hypodense regions most consistent with an intraparenchymal hematoma (Fig. 1). In addition, a moderate amount of intermediate density ascites, possibly representing hemoperitoneum, was visualized. A splenic ultrasound demonstrated an atypical color Doppler of the splenic artery, prompting a computed tomography angiogram, which confirmed the presence of a small splenic pseudoaneurysm (Fig. 2). The area was selectively catheterized and embolized via the deployment of 3 coils in the distal splenic artery (Fig. 3). The patient's postprocedure course was remarkable for intermittent right upper quadrant pain possibly secondary to ongoing splenic infarction. The severity of his symptoms ultimately diminished and he returned to the chronic care facility where he resumed feeding therapy.
Pancreatitis is a known risk factor for splenic artery pseudoaneurysm (SAP) formation and is believed to be the result of weakening of the blood vessel wall by pancreatic enzymes. This process ultimately results in the formation of a vascular cystic structure generally referred to as a “pseudoaneurysm.” A pseudoaneurysm wall comprises only intima and media as opposed to a true aneurysm, which also contains the outermost connective tissue covering, or adventitia (1).
Several pathogenic mechanisms have been suggested. Flati et al (2) posit that in the early phase of acute pancreatitis severe pancreatic inflammation and pancreatic necrosis initiate damage that is characterized by elastolytic erosion of any vascular structure that is near the necrotizing process. Such activity leaves the vessel wall vulnerable to rupture or pseudoaneurysm formation. Other proposed mechanisms include vascular erosion from enzymes within a long-standing pseudocyst, or direct compression from the pseudocyst itself resulting in ischemia (2).
Affected vessels are typically in close proximity to the pancreas, most commonly the splenic artery. The hepatic, gastroduodenal, and pancreaticoduodenal arteries can also be affected. Ahmed et al (3) reported a rare case of pancreatic pseudoaneurysm formation involving the superior mesenteric artery in a 6-year-old female with hereditary pancreatitis.
The diagnosis of SAP is established most commonly by computed tomography, which may detect a cystic structure in the pancreas (3). The appearance is similar to that of a pseudocyst; however, contrast serves to enhance a surrounding region of fluid that represents an enclosed area of hemorrhage. Ultrasound can identify a pseudoaneurysm, but this test is operator dependent and may be limited because of obesity and shadowing from bowel gas. Direct catheter angiography is considered to be the criterion standard for diagnosis. In addition to confirming the diagnosis it can provide a means of therapy because embolization of the pseudoaneurysm can be accomplished during this procedure (4).
Treatment should be initiated without delay because the risk of spontaneous rupture is high and resultant hemorrhage confers a high rate of mortality. Before the refinement of endovascular techniques, treatment relied on surgery. Simple excision involved proximal and distal ligation of the artery, conserving the branches arising from the short gastric vessels and the dorsal branch of the pancreas, or direct ligation of the pseudoaneurysm. Partial or total splenectomy was considered as well as resection of pancreatic parenchyma depending on the extent and location of the lesion (5).
Recently, transcatheter embolization has become more common. Although success rates of approximately 85% are lower than those of direct surgical intervention, associated operative morbidity and mortality rates are significantly reduced (1). If transcatheter embolization of the pseudoaneurysm is chosen, then most authors recommend embolization of only the feeding vessels, which results in pseudoaneurysm thrombosis. For this procedure, the artery from which the pseudoaneurysm originates is selectively catheterized and embolized with coils just distal and proximal to the lesion. This effectively excludes the aneurysm from circulation and enables thrombosis (5).
An extensive literature search using the complete OVID database revealed 147 reported cases of SAP formation in the English-language literature. In a large series from the Mayo Clinic, 10 SAPs were compiled in 18 years (4). The youngest patient was 35 years of age. Srinivas et al (6) reported a case of SAP in a 12-year-old boy with chronic calcific pancreatitis who was managed surgically.
Here, we report a rare case of SAP in a 5-year-old child with hereditary pancreatitis that was managed via transcatheter embolization.
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3. Ahmed HK, Hagspiel KD, McGahren ED III. Pancreatic pseudoaneurysm in a child with hereditary pancreatitis: diagnosis with multidetector CT angiography. Pediatr Radiol 2004; 34:656–659.
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6. Srinivas M, Kataria R, Bhatnagar V. Intra-pancreatic splenic pseudoaneurysm. A rare complication of chronic calcific pancreatitis. Pediatr Surg Int 1998; 13:171–174.
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