Disorders of the Pancreas

Abstract

The pancreas is a complex retroperitoneal organ that has both major digestive and endocrine functions. In fact, the totality of the role of the pancreas has not been fully defined. Disorders of the pancreas can result from a congenital anatomic abnormality or dysfunction of either the digestive or endocrine components. The endocrine function of the pancreas is centered in the cells of the islets of Langerhans. Although the islet cells make up only approximately 2% of the pancreatic mass, they play a much larger physiologic role. There are four major types of cells within the islets, each secreting one or more specific peptides. Disorders related to each cell type or peptide can occur. The most common of these disorders is related to the Beta cells, which regulate insulin secretion. This significant topic will be covered separately. We will cover the anatomic, non-insulin endocrine, and inflammatory disorders of the pancreas.

Appendices

Summary Points

Tumors arising from cells in the islets of Langerhans can produce symptoms by oversecretion of peptides normally produced by these cells: insulinoma, gastrinoma, glucagonoma, VIPoma.

Hyperinsulinsm is the most common endocrine disorder of the pancreas in children.

Gastrinoma causes peptic ulcer disease and diarrhea (Zollinger-Ellison syndrome) due to hypergastrinemia.

Gastrinomas are often very small, can arise within the pancreas or the wall of the small bowel, and may be multiple or malignant with metastases.

Single islet-cell tumors can be enucleated or removed by partial pancreatectomy, while multifocal or metastatic disease is treated medically or, for gastrinoma, near-total gastrectomy.

Acute pancreatitis in children can be caused by gallstones, anatomic abnormalities such as pancreas divisum, or idiopathic.

Acute pancreatitis is managed with supportive measures and attempts to treat the underlying cause.

Pancreatic pseudocysts are the result of a contained pancreatic fistula and usually resolve spontaneously.

Surgical therapy of pancreatic pseudocyst is by establishing drainage into the stomach, duodenum, or jejunum.

Editor’s Comment

The pancreas is an organ that is treated with a great deal of respect by surgeons. Most of the pancreatic disorders commonly seen in adults are much less prevalent in children but are much better tolerated by children. Annular pancreas is probably not a cause of duodenal obstruction but rather an anatomic variant that occurs in the setting of duodenal atresia. Although previous concerns about the risks of dividing the pancreas are probably exaggerated, there is no reason to disturb it while creating a duodenoduodenostomy for repair of the duodenal atresia. Pancreas divisum is probably a normal anatomic variant and not a frequent cause of acute pancreatitis. Nevertheless, some patients with recurrent or chronic pancreatitis appear to benefit from endoscopic sphincterotomy.

Most cases of acute pancreatitis in children are idiopathic though the workup should include a search for gallstones, severe hyperlipidemia, toxins (L-asparaginase chemotherapy), anatomic abnormalities, cysts, and a positive family history. Treatment is supportive and individualized but Ranson’s criteria are relatively useless and imaging does not correlate with severity. Pancreatic necrosis is uncommon and infected pancreatic necrosis requiring intervention is exceedingly rare. If the patient is relatively stable, percutaneous drainage or laparoscopic debridement might be reasonable before embarking on a morbid and protracted course of serial surgical resections.

Given enough time, pancreatic pseudocysts almost always eventually resolve spontaneously. Indications for intervention include persistent symptoms or a cyst that persists for more than 6 weeks. Radiology-guided percutaneous drainage and placement of internal stents is gaining in popularity and seems to work in many cases. When indicated, surgical therapy should be performed using a minimally invasive approach whenever possible. Chronic pancreatitis with a dilated pancreatic duct responds well to Roux-en-Y pancreatico-jejunostomy (Puestow procedure) but the drainage should be extended to include the head of the pancreas (Frey procedure).

Pancreatic tumors include not only endocrine tumors such as insulinoma and gastrinoma but also pancreatoblastoma, solid-cystic papillary tumor, inflammatory myofibroblastic tumor, and sarcoma. The treatment is primarily surgical but should be coordinated with an experienced pediatric oncologist. The operations are the same as those used in adults, namely distal pancreatectomy for lesions in the body or tail and Whipple procedure for lesions in the head of the pancreas. These are very rarely performed but very well tolerated in children. Aggressive attempts to balance negative margins and normal function of adjacent organs should be made. Nevertheless, depending on the tumor type, recurrence and a poor prognosis are relatively common.

Preoperative Preparation

• Intravenous fluid resuscitation

• Parenteral nutrition

• Resolution of acute pancreatitis

Diagnostic Studies

• Abdominal MRI

• Abdominal CT scan

• Ultrasonography

• MRCP

• ERCP

Technical Points

It is unnecessary and potentially dangerous to disturb the pancreas in the case of duodenal atresia with annular pancreas.

A Puestow procedure is for chronic pancreatitis and allows drainage of an enlarged and chronically obstructed pancreatic duct by way of a Roux-en-Y panreatico-jejunostomy.

Pancreatic pseudocysts that do not resolve spontaneously should be drained by creating an anastomosis between the wall of the pseudocyst and an adjacent hollow viscus, namely stomach, duodenum, or jejunum, depending on which organ the cyst has adhered to.

Intra-operative exploration for an islet cell tumor should be systematic and thorough, with mobilization of the spleen and body of the pancreas to allow for bimanual palpation.

Intra-operative ultrasound is useful for the localization of islet-cell tumors.

Pancreatic necrosis can be treated non-operatively except when they become infected, in which case surgical debridement and drainage are required.

Large closed-suction drains should be used in all procedures in which the pancreatic duct is entered.