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.

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.

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.

If pancreatitis is suspected, amylase and lipase levels should be measured, as they may support a clinical diagnosis. However, these laboratory test findings alone are not reliable or cost effective as a screening tool, and the magnitude of enzyme elevation does not correlate with the severity of pancreatic injury.[12]

Elevated serum or urine amylase levels aid in the diagnosis of pancreatitis and peak 48 hours after onset. Serum amylase levels are typically elevated for as long as 4 days. Amylase levels have been found to be within the reference range in 10-15% of patients with pancreatitis. Amylase levels can be elevated in patients with other abdominal conditions, but typically, they are not as high as levels found in patients with pancreatitis.

Serum lipase is more specific than amylase for acute pancreatitis, and typically, lipase levels remain elevated 8-14 days longer than amylase levels. Serum lipase levels can also be elevated in patients with other diseases or conditions; therefore, all laboratory results should be evaluated in the context of the clinical presentation.

Other laboratory abnormalities found in patients with pancreatitis may include coagulopathies, leukocytosis, hyperglycemia, glucosuria, hypocalcemia, hyperbilirubinemia, and elevated gamma glutamyl transpeptidase.

Urinary levels of trypsin activator peptide (TAP) may help determine the severity of the pancreatitis.

Ultrasonography and CT scanning are the preferred imaging modalities used to diagnose and follow the course of pancreatitis and pancreatic pseudocysts. Ultrasonography is the primary screening tool for evaluation of the pediatric pancreas, due to the absence of ionizing radiation and ability to image without sedation. CT scanning may be better suited for evaluation of chronic pancreatitis and its complications, pancreatic trauma, and neoplastic conditions and is often used to further evaluate abnormalities found on ultrasonography.

Ultrasonography findings may include a focally or diffusely enlarged, hypoechoic, sonolucent, or edematous pancreas; dilated pancreatic ducts; a pancreatic mass; a fluid collection or peripancreatic fluid; an abscess; or a pseudocyst demonstrated as a well-defined, hypoechoic mass, which may be multilocular.

CT scan findings include an enlarged gland with ill-defined margins; peripancreatic fluid; areas of decreased or enhanced density; or pseudocysts with a well-defined wall or capsule and central area of low attenuation. CT scanning is a better modality for evaluating presence and extent of pancreatic necrosis and inflammation of peripancreatic fat. Of note, findings on imaging studies initially appear normal in 20% of children with acute pancreatitis.

MRI is another modality to diagnose pancreatitis and is used for the same indications as CT scanning. 

Endoscopic retrograde cholangiopancreatography (ERCP) is essential for evaluation of pancreatic and biliary anomalies. ERCP can aid in the diagnosis of various ductal abnormalities or obstructions and may serve as a therapeutic intervention (ie, sphincterotomy, stent placement).

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive alternative to ERCP but lacks therapeutic capabilities.

Roentgenography may demonstrate nonspecific findings ranging from a distended loop of small intestine (ie, sentinel loop), calcifications, radio-opaque gallstones, dilation of the transverse colon (ie, cutoff sign), ascites, peripancreatic extraluminal gas bubbles, ileus, left-sided basal pleural effusion, and blurring of the left psoas margin to pancreatic calcifications from chronic or recurrent pancreatitis.

Acute pancreatitis is characterized by enzymatic necrosis and inflammation of the pancreas. Focal areas of fat necrosis are interspersed with areas of interstitial hemorrhage secondary to destruction of blood vessels. In severe cases, large blue-black hemorrhagic foci are interspersed with yellow-white chalky areas of fat necrosis.

Chronic pancreatitis is characterized by irreversible destruction of the pancreatic parenchyma and subsequent replacement with fibrous tissue. Histologic features include intraglandular fibrosis, acinar cell destruction, lymphocytic infiltration, and pancreatic duct obstruction. The pancreatic ducts are dilated and obstructed with protein plugs in their lumens. Grossly, the gland is hard.

Pancreatic pseudocysts are localized collections of pancreatic secretions walled off by granulation tissue that lack a true epithelial lining. The stomach, duodenum, small bowel, colon, or omentum may abut or form part of the pseudocyst capsule.

The goal of medical management of acute pancreatitis is to achieve adequate rehydration, analgesia, and pancreatic rest and to restore normal metabolic homeostasis. In patients with severe pancreatitis, oral intake is restricted and parenteral nutrition is initiated within 3 days to prevent catabolism. In cases of intractable vomiting or ileus, nasogastric suction is indicated to help intestinal-pancreatic rest by eliminating gastric secretions in the duodenum, the most potent activator of pancreatic secretion. Fluid electrolyte and mineral imbalances should be corrected urgently. 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. For alleviation of pain, meperidine is preferred over morphine because of its decreased risk of ampullary spasm.

Surgical management of acute pancreatitis is rarely required. Surgical intervention is only needed if the symptoms are severe and prolonged or complicated by necrosis or abscess formation that requires debridement. Peritoneal lavage has been used in adults in an effort to reduce the incidence of secondary infection; however, this has not been through trials with children to test its efficacy. If underlying pancreaticobiliary disease is present, surgical intervention is required for cure. Most surgical interventions are used in patients with chronic or relapsing pancreatitis. The goal of surgery in this instance is to alleviate pain and preserve the exocrine and endocrine functions of the pancreas. Surgical therapies include longitudinal pancreaticojejunostomy, distal pancreatectomy with Roux-en-Y pancreaticojejunostomy, decompression of pancreatic ducts, repair of pancreatic divisum, and sphincteroplasty.

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 essential to identify the ductal disruption, and findings direct definitive surgical therapy.

Acute pancreatic pseudocysts smaller than 5 cm in diameter are managed with observation for 4-6 weeks because most resolve spontaneously. Pancreatic pseudocysts larger than 5 cm in diameter may require surgical intervention; however, conservative therapy is required for approximately 4-6 weeks to allow the cyst wall to mature. Results from a study by Ford et al indicate that pancreatic pseudocysts larger than 10 cm in diameter in children are associated with increased risk for spontaneous rupture and, thus, require aggressive monitoring.[13]

Chronic pancreatic pseudocysts (>3 mo duration) are best treated by surgical interventions. Ultrasonography-guided or CT-guided percutaneous drainage, endoscopic drainage, and internal drainage have been used with success. Surgical approaches for internal drainage are largely determined by the anatomic location of the pseudocyst. If the pseudocyst is adherent to the posterior wall of the stomach, cystogastrostomy is performed. If the cyst is present in the head of the pancreas, cystoduodenostomy is considered. For other cysts not adherent to the stomach or duodenum, cystojejunostomy is preferred. Distal pancreatectomy is considered when the pseudocyst is in the tail of the gland.

Managing pancreatic pseudocysts with endoscopic treatment has been an increasing trend. Recent evidence has demonstrated that, in skilled hands, endoscopic treatment is safe and effective (for short-term and long-term treatment). Some authors suggest that endoscopic treatment should be the first choice. Success rate is as high as 85%. Surgical treatment can be reserved for those cases that fail endoscopic treatment.

Preoperative studies with ultrasonography and CT scanning, the preferred imaging modalities used to diagnosis and follow the course of pancreatitis and pancreatic pseudocysts, are important to assess the character and size of the pseudocyst. ERCP is essential to assess various ductal abnormalities or pseudocyst communication with the pancreatic duct to determine definitive operative therapy.

Although pseudocyst formation is an uncommon sequela of acute or chronic pancreatitis in children, complications of pancreatic pseudocysts include spontaneous rupture, hemorrhage, and infection. Pseudocysts can be medically managed with pancreatic rest or surgically by internal or external drainage. While under medical therapy, rupture is the major complication associated with pseudocysts larger than 10 cm.

Cases of uncomplicated acute pancreatitis usually resolve within 2-4 days. The management of acute pancreatitis is predominately supportive medical therapy, with intravenous hydration, pain control, and bowel rest. Parenteral nutrition may be required for prolonged episodes. Diagnosis of the specific cause of pancreatitis is important to elucidate, as there is a 9% recurrence rate, most of which are diagnosed with idiopathic recurrent pancreatitis or structural anomalies.

The most frequent cause of acute pancreatitis in pediatrics is related to medication administration. If a medication is suspected, it should be stopped immediately and other alternatives should be investigated. Etiologies related to trauma, systemic disease, or anatomic variants are important to determine and direct further medical or surgical interventions. Surgical management is used to address complications of pancreatitis, including hemorrhage, necrosis, ductal fistulae, and pseudocysts.

Surgical management of pancreatic pseudocysts is highly successful. Recurrence rates and mortality rates are low. Internal drainage is associated with lower recurrence rates compared to percutaneous or endoscopic drainage. Transendoscopic and percutaneous drainage of pancreatic pseudocysts have been predominately performed in the adult population, and further investigation and comparison of these techniques in children is warranted to determine the optimal management of this disease.

The use of total pancreatectomy with islet cell transplantation is undergoing evaluation for the treatment of chronic abdominal pain in children with chronic pancreatitis.