The pancreas

THE PANCREAS
Pancreatic function tests
Pancreatic exocrine function can be assessed by directly measuring pancreatic secretion in response to a standardised stimulus. The stimulus to secretion can be physiological, e.g. ingestion of a test meal, as in the Lundh test, or pharmacological, e.g. intravenous injection of a hormone such as secretin or CCK. Measurement of the enzyme elastase in stool is simple and specific. E-Absence of the enzyme elastase indicates exocrine insufficiency.
Investigation of the pancreas.
Serum enzyme levels
Pancreatic function tests
Morphology Ultrasound scan Computed tomography Magnetic resonance imaging Endoscopic retrograde
Cholangiopancreatography Endoscopic ultrasound
Plain radiography Chest Upper abdomen
Causes of raised serum amylase level other than acute pancreatitis
? Upper gastrointestinal tract perforation ? Mesenteric infarction ? Torsion of an intra-abdominal viscus ? Retroperitoneal haematoma? Ectopic pregnancy
? Macroamylasaemia? Renal failure ? Salivary gland inflammation

CONGENITAL ABNORMALITIES ;Cystic fibrosis
This is inherited as an autosomal recessive condition,and is characterised by elevated sodium and chloride ion concentrations in sweat. The mother may notice that the child is salty when kissed.
Chronic pulmonary disease arises from plugging of bronchi and bronchioles.
The diagnosis can be made by genetic testing (which may be part of prenatal or newborn screening) and by the sweat test. Levels of sodium and chloride ions in the sweat above 90 mmol/L confirm the diagnosis.
Treatment is aimed at control of the secondary consequences of the disease. Pulmonary function is preserved with aggressive physiotherapy and antibiotics. Malabsorption is treated by administration of oral pancreatic enzyme preparations. The diet should be low in fat but contain added salt to replace the high losses in the sweat.

Pancreas divisum
Pancreas divisum occurs when the embryological ventral and dorsal parts of the pancreas fail to fuse . The dorsal pancreatic duct becomes the main pancreatic duct and drains most of the pancreas through the minor or accessory papilla.
The incidence of pancreas divisum ranges from 25 to 50 per cent in patients with recurrent acute pancreatitis, chronic pancreatitis and pancreatic pain. A large volume of secretions flowing through a narrow papilla probably leads to incomplete drainage, which may then cause obstructive pain or pancreatitis. Certainly in patients with idiopathic recurrent pancreatitis, pancreas divisum should be excluded. The diagnosis can be arrived at by MRCP, EUS or ERCP, augmented by injection of secretin if necessary. There may be changes indicative of obstruction or chronic inflammation in the dorsal duct system. Endoscopic sphincterotomy and stenting of the minor papilla may relieve the symptoms. Surgical intervention can take the form of sphincteroplasty, pancreatojejunostomy or even resection of the pancreatic head.
Annular pancreas
This is the result of a failure of complete rotation of the ventral pancreatic bud during development, so that a ring of pancreatic tissue surrounds the second or third part of the duodenum. It is most often seen in association with congenital duodenal stenosis or atresia and is therefore more prevalent in children with Down’s syndrome. Duodenal obstruction typically causes vomiting in the neonate . The usual treatment is bypass (duodenoduodenostomy). The disease may occur in later life as one of the causes of pancreatitis, in which case resection of the head of the pancreas is preferable to lesser procedures.
Ectopic pancreas
Islands of ectopic pancreatic tissue can be found in the submucosa in parts of the stomach, duodenum or small intestine (including Meckel’s diverticulum), the gall bladder, adjoining the pancreas, in the hilum of the spleen and within the liver. Ectopic pancreas may also be found in the wall of an alimentary tract duplication cyst .
Congenital cystic disease of the pancreas
This sometimes accompanies congenital disease of the kidneys and liver, and occurs as part of the von Hippel–Lindau syndrome.