Pediatric Pancreatitis and Pancreatic Pseudocyst

Pancreatitis, although uncommon during childhood, is associated with significant morbidity and mortality. Pancreatitis is characterized by inflammation of the pancreas, clinical signs of epigastric abdominal pain, and elevated serum digestive enzymes. Pancreatitis can be local or diffuse and is classified as acute, chronic, inherited, necrotic, or hemorrhagic. Occasionally, pancreatitis is complicated by the formation of a fibrous-walled cavity filled with pancreatic enzymes, termed a pseudocyst. See the images below.

This CT scan of the abdomen in the region of the pancreas demonstrates a large well-marginated cystic structure that represents a pancreatic pseudocyst.

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This real-time ultrasonography of the abdomen, with attention to the right upper quadrant, revealed a loculated fluid collection in the hilum of the liver. This was compatible with a pancreatic pseudocyst. Differential diagnosis included a large choledochal cyst.

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For excellent patient education resources, visit eMedicineHealth's Digestive Disorders Center. Also, see eMedicineHealth's patient education articles Pancreatitis and Abdominal Pain in Children.

Pancreatitis in children is uncommon and represents a diagnostic challenge for clinicians. Although most adult cases of pancreatitis are caused by alcohol abuse or gallstone disease, the etiology for pancreatitis in children is diverse. The predominant causes include abdominal trauma (23%), anomalies of the pancreaticobiliary system (15%), multisystem disease (14%), drugs and toxins (12%), viral infections (10%), hereditary disorders (2%), and metabolic disorders (2%). In up to 25% of cases the etiology of childhood pancreatitis is unknown. In the United States, trauma is responsible for 15-37% of cases. ^[1]

In general, the prognosis of children with acute pancreatitis is excellent, although pseudocysts have been reported to complicate 10-23% of acute episodes. In addition, when associated with abdominal trauma, the frequency rate of pseudocyst identification is higher than 50%. Approximately 60% of pancreatic pseudocysts that are caused by blunt trauma require surgical intervention.

Pancreatitis is uncommon in the pediatric population. Importantly, clinicians evaluating patients with symptoms of abdominal pain should have a high index of suspicion for pancreatitis. Pancreatitis originates with blockage or disruption of the collecting ducts and damage to the pancreatic acinar cells, which leads to activation and release of digestive enzymes. The activated enzymes autodigest the pancreatic parenchyma, causing inflammation and, potentially, necrosis. Localized collections of pancreatic secretions may become walled off by granulation tissue and form a pseudocyst either within the pancreatic tissue or immediately adjacent to it.

Frequency

As a result of limited case reporting and underdiagnosis by physicians, the frequency and true incidence of pancreatitis in children is unknown. Pseudocysts complicate acute pancreatitis in approximately 10-23% of cases. The incidence of pancreatic pseudocysts is greater than 50% when associated with traumatic injury to the abdomen.

Common causes of pancreatitis are extensive but include blunt abdominal trauma (eg, motor vehicle collision, abuse, bicycle accident where the abdomen is compressed by the handlebars), systemic infection (eg, mumps, rubella, coxsackie virus B, cytomegalovirus [CMV], human immunodeficiency virus [HIV]), pancreaticobiliary malunion, congenital anomalies of the pancreato-biliary junction, pancreas divisum, congenital sphincter of Oddi abnormality, choledochal cysts, or choledocholithiasis.

Use of hyperalimentation, medications (eg, azathioprine, tetracycline, L-asparagine, valproic acid, steroids and immunosuppressive agents), and metabolic abnormalities (eg, hypertriglyceridemia, hypercalcemia, cystic fibrosis) may incite pancreatitis.

Hereditary pancreatitis in children, the second most common congenital pancreatic disorder following cystic fibrosis, is characterized by an alteration in the long arm of chromosome 7, which yields an aberrant trypsinogen protein that may induce autodigestion of the pancreas.

The specific inciting factors causing pancreatitis remain to be elucidated. Pancreatitis may be induced by primary acinar cell injury as a result of viral infections, drugs, ischemia, and direct trauma.

Pancreatitis may originate from a disruption of the ductal system and subsequent excretion of digestive enzymes from the acinar cells of the pancreas. Normally these cells release inactive enzymes into collecting ducts, which then drain into the main or accessory pancreatic ducts emptying directly into the duodenal lumen. If obstruction or disruption of these ducts occurs, the pancreatic secretions are activated within the parenchyma of the pancreas and initiate autodigestion of the pancreatic tissue.

Interstitial edema is an early finding. Exacerbation of pancreatitis may result in pancreatic necrosis, blood vessel occlusion or disruption inciting hemorrhage, and systemic inflammatory response syndrome with multiorgan failure. Collections of pancreatic secretions often become walled off by granulation tissue to form a pseudocyst either within or adjacent to the pancreas. Predominantly, the pseudocyst is localized in the lesser sac behind the stomach. The stomach, duodenum, colon, small bowel, or omentum may abut or form part of the pseudocyst capsule.

Classically, pancreatitis in adults presents with midepigastric pain radiating to the back. In children, the presenting signs and symptoms can be quite varied. Most commonly, a child with acute pancreatitis presents with abdominal pain (87%) with vomiting (64%) and abdominal tenderness (77%) with abdominal distension (18%). Other, less common clinical signs include fever, tachycardia, hypotension, jaundice, abdominal guarding, rebound tenderness, and decreased bowel sounds. Eating may exacerbate the abdominal pain. Acutely ill children may lie on their side with the hips and knees flexed. The pain typically increases in intensity for 24-48 hours. The clinical course for acute pancreatitis is variable. Often, children may require hospitalization for analgesia, bowel rest, and rehydration with fluid and electrolyte therapy.

Acute hemorrhagic pancreatitis rarely occurs in children. This is a life-threatening condition with a mortality rate approaching 50% because of shock, systemic inflammatory response syndrome with multiple organ dysfunction, acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation, massive GI bleeding, and systemic or peritoneal infection. Physical examination findings associated with hemorrhagic pancreatitis may include a bluish discoloration of the flanks (ie, Grey Turner sign) or periumbilical region (ie, Cullen sign) because of blood accumulation in the fascial planes of the abdomen. Additional signs include pleural effusions, hematemesis, melena, and coma.

Chronic pancreatitis in children is associated with trauma, systemic disease, and pancreaticobiliary malformations, most commonly pancreatic divisum. In the United States, the most common cause of chronic relapsing pancreatitis in children is hereditary pancreatitis. Patients with this disease typically present with chronic abdominal pain that can be difficult to treat. These patients have recurrent episodes of upper abdominal pain associated with varying degrees of pancreatic dysfunction and have increased risk of developing pancreatic insufficiency, adenocarcinoma, and pancreatic pseudocysts.

Children with pancreatic pseudocysts may present with localized abdominal pain and a palpable tender epigastric mass or abdominal fullness. Additional symptoms include jaundice, chest pain, nausea, vomiting, anorexia, weight loss, fever, ascites, and rarely, GI hemorrhage.

Medical management

Medical management of acute pancreatitis aims to achieve adequate rehydration, analgesia, and pancreatic rest and to restore normal metabolic homeostasis. Antacids or H2-histamine blockers are useful to prevent gastritis and reduce duodenal acid exposure. In severe pancreatitis, oral intake is restricted and parental nutrition is started within 3 days to prevent catabolism. In cases of intractable vomiting or ileus, nasogastric suction is beneficial to prevent vomiting, manage ileus, and provide pancreatic rest. Antibiotic therapy is indicated for systemic infections or sepsis. Acute pancreatitis should resolve in 2-7 days with adequate resuscitation. In the setting of chronic relapsing pancreatitis, pancreatic enzyme supplementation, insulin, and elemental or low-fat diets are useful adjuncts to maximize nutritional status. ^{[2, 3, 4]}

Surgical management

Surgical intervention is indicated for the management of congenital anatomic defects (eg, pancreatic divisum) and other complications associated with acute pancreatitis (eg, pancreatic ascites, intra-abdominal abscess collections, pancreatic pseudocyst). Acute pancreatic pseudocysts are managed with observation for 4-6 weeks because most resolve spontaneously. Chronic pancreatic pseudocysts (>3 mo) are best treated by surgical interventions such as ultrasonography-guided or CT-guided percutaneous drainage, ^[5] endoscopic drainage, or internal drainage via cyst gastrostomy or enterostomy. Surgery for pancreatic ductal disruption or compromise (ie, acute traumatic pancreatitis with ductal injury) is indicated after medical failure. Endoscopic retrograde cholangiopancreatography (ERCP) or intraoperative pancreatic ductography is invaluable in determining the site of ductal disruption and directs surgical decision-making to the most appropriate operative procedure. ^{[6, 7, 8, 9]}

Operative management of chronic pancreatitis in children is controversial. Indications for operative intervention include unsuccessful conservative medical therapy, intractable pain, impaired nutrition, and narcotic addiction. Surgical options include distal pancreatectomy with Roux-en-Y pancreaticojejunostomy (ie, Duval procedure), lateral pancreaticojejunostomy (ie, Puestow procedure), or ERCP sphincteroplasty. Recently, a few pediatric patients with chronic pancreatitis and chronic abdominal pain were successfully treated with total pancreatectomy and islet cell transplantation. ^{[10, 11]}

Treatment of pediatric patients with chronic pancreatitis requires the collaborative efforts of multispecialty teams that include gastroenterologists, surgeons, pharmacologists, nutritionists, child life specialists, psychologists, and psychiatrists.

The pancreas is divided up into a head, body, and tail, although no distinct anatomic borders indicate these divisions. Most of the pancreas is extraperitoneal, with just a portion of the tail coming through the mesenteric folds. The head is to the right of L2, the body overlies L1, and the tail rises up to the left of T12. The abdominal aorta and vena cava function to cushion the pancreas from injury against the vertebral bodies. However, with crushing or blunt abdominal trauma, the pancreas can be injured by compression against the vertebra.

Numerous congenital abnormalities of the pancreatic biliary system have been described. Pancreatic divisum, which occurs in 5-15% of the population, results from unsuccessful fusion of the embryonic ventral and dorsal pancreatic buds. As a result, the accessory duct of Santorini derived from the dorsal bud drains the majority of the pancreas. Because the accessory duct is smaller in caliber than the duct of Wirsung, inadequate pancreatic drainage may result in chronic pain and recurrent pancreatitis.

Sphincteroplasty is contraindicated in patients with evidence of intrapancreatic ductal obstruction. Pancreatic pseudocysts with associated major ductal disruption or a transected pancreas require operative therapy with cyst enterostomy. Definitive management with subtotal or total pancreatectomy is associated with considerable morbidity and mortality due to loss of both endocrine and exocrine functions of the pancreas. Generally, surgery is not indicated in children; however, it may be considered in cases of intractable pain and diffuse parenchymal damage without ductal dilation.