Pancreatic duct obstruction

AP is initiated by premature activation of pancreatic zymogens (inactive enzymes) within the acinar cells, pancreatic ischemia, or pancreatic duct obstruction. 

Pancreatic duct obstruction by a gallstone at the ampulla of Vater. Obstruction can lead to pancreatitis, from induction of bile reflux, which eventually damages acinar cells of the pancreas. 

Obstructive Pancreas divisum, pancreatic duct obstruction... 

Fig. 30.14a,b. Malignant neuroendocrine tumor, a The axial CT image shows a large, inhomogeneous, partially hyper-vascular tumor in the pancreatic head, b The coronal MPR shows the tumor and the lack of pancreatic duct obstruction and sub-... 

Amylase enters the blood largely via the lymphatics. An increase in hydrostatic pressure in the pancreatic ducts leads to a fairly prompt rise in the amylase concentration of the blood. Neither an increase in volume flow of pancreatic juice nor stimulation of pancreatic enzyme production will cause an increase in senm enzyme concentration. Elevation of intraductal pressure is the important determinant. Stimulation of flow in the face of obstruction can, however, augment the entry of amylase into the blood, as can disruption of acinar cells and ducts. A functional pancreas must be present for the serum amylase to rise. Serum amylase determination is indicated in acute pancreatitis in patients with acute abdominal pain where the clinical findings are not typical of other diseases such as appendicitis, cholecystitis, peptic ulcer, vascular disease or intestinal obstruction. In acute pancreatitis, the serum amylase starts to rise within a few hours simultaneously with the onset of symptoms and remains elevated for 2 to 3 days after which it returns to normal. The peak level is reached within 24 hours. Absence of increase in serum amylase in first 24 hours after the onset of symptoms is evidence against a diagnosis of acute pancreatitis (76). 

Malabsorption of protein and fat occurs when the capacity for enzyme secretion is reduced by 90%. A minority of patients develop complications including pancreatic pseudocyst, abscess, and ascites or common bile duct obstruction leading to cholangitis or secondary biliary cirrhosis. 

Cystic fibrosis can obstruct pancreatic ducts due to mucous plugging and impaired secretion of pancreatic enzymes such as lipase and phospholipases, which decreases hydrolysis and uptake oftri-acylglycerols. 

Hirano T, Manabe T. Human urinary trypsin inhibitor, urinastatin, prevents pancreatic injuries induced by pancreaticobiliary duct obstruction with caerulein stimulation and systemic hypotension in the rat. Arch Surg 1993 128 1322-1329. 

It should be noted that deficiency states for some vitamins (e.g., pantothenic acid) are practically unknown in human beings. In such cases, deficiency states may be simulated by feeding the subject an appropriate vitamin antagonist. In another series of situations, vitamin deficiencies can be brought about by interfering with their absorption intentionally or may be the result of a disease process. Thus, fat-soluble vitamin deficiency may develop in cases of fat malabsorption syndromes (steatorrhea) sprue, pancreatic insufficiency, and bile duct obstruction. 

Normally there is very little fat in the feces. However, fat content in stools may increase because of various fat malabsorption syndromes. Such increased fat excretion is steatorrhea. Decreased fat absorption may be the result of failure to emulsify food contents because of a deficiency in bile salts, as in liver disease or bile duct obstruction (stone or tumor). Pancreatic insufficiency may result in an inadequate pancreatic lipase supply. Finally, absorption itself may be faulty because of damage to intestinal mucosal cells through allergy or infection. An example of allergy-based malabsorption is celiac disease, which is usually associated with gluten intolerance. Gluten is a wheat protein. An example of intestinal infection is tropical sprue, which is often curable with tetracycline. Various vitamin deficiencies may accompany fat malabsorption syndromes. 

In cystic fibrosis, the pancreatic ducts become obstructed by viscous mucus. Consequently, digestion of which of the following substances would be most impaired ... 

Obstruction of the pancreatic duct by a calculus or by carcinoma of the pancreas may increase serum LPS activity depending on the location of the obstruction and the amount of remaining functioning tissue. In patients with a reduced glomerular filtration rate, the serum LPS activity is increased. Thus care should be exercised in the interpretation of elevated serum LPS values in the presence of renal disease. Finally, investigation of the biliary tract by endoscopic retrograde pancreatography or treatment with opiates (which causes the sphincter of Oddi to contract) may increase serum LPS activity. 

Although vitamin K deficiency in the adult is uncommon, the risk is increased for fat malabsorption states (bile duct obstruction, cystic fibrosis, and chronic pancreatitis) and liver disease. Risk is also increased by the use of drugs that interfere with vitamin K metabolism, such as the coumarin anticoagulants (e.g., warfarin) and antibiotics containing the N-methylthiotetrazole side chain (e.g., cephalosporin). ... 

Obstruction of the main pancreatic duct as a result of a gallstone lodged in or near to the hepatopancreatic ampulla can result in acute pancreatitis. One theory is that obstruction increases the pressure in the main pancreatic duct. The increase in pressure causes interstitial edema, which impairs the blood flow to the acinus. The lack of blood flow leads to ischemic injury of the acinar cell, resulting in release of the digestive enzymes into the interstitial space. How this leads to premature activation of the proenzymes stored in the acinar cell is unclear. 

Snape, W. J., Long, W. B., Trotman, B. W., Marin, G. A., and Czaja, A. J., Marked alkaline phosphatase elevation with partial common bile duct obstruction due to calcific pancreatitis. Gastroenterology 70, 70-73 (1976). 

Michael was scheduled for endoscopic retrograde cholangiopancreatography (ERCP). (An ERCP involves cannulation of the common bile duct—and, if necessary, the pancreatic duct— through a tube placed through the mouth and stomach and into the upper small intestine.) With this technique, a stone can be snared in the common duct and removed to relieve an obstruction. 

Alcohol excess may produce proteinaceous plugs in the small pancreatic j ducts, causing back pressure injury and autodigestion of the pancreatic acini drained by these obstructed channels. This process causes one form of acute pancreatitis. A1 Martini had an episode of acute alcohol-induced pancreatitis superimposed on a more chronic alcohol-related inflammatory process in the pancreas—in other words, a chronic pancreatitis. As a result of decreased secretion of pancreatic lipase through the pancreatic ducts and into the lumen of the small intestine, dietary fat was not absorbed at a normal rate, and steatorrhea (fat-rich... 

Chronic pancreatitis is a rare entity in children. Amongst the principal causes of chronic pancreatitis are hereditary pancreatitis, autoimmune conditions (sclerosing cholangitis), and CF. CT features of chronic pancreatitis include a focal or diffuse increase in pancreatic size, dilatation of the main pancreatic duct (almost always present), intraductal calcifications, or pseudocyst formation. ERCP can be used in children with unknown pancreatitis to identify and treat cases of biliary obstruction and structural cases of chronic pancreatitis. 

The excretory products of the kidneys and the excretory glands may be eliminated directly through a specific canal into an environment in direct contact with the outside—such as the skin, the mouth, the salivary gland, the intestine, or the pancreatic duct—or they may be collected into reservoirs, such as the gallbladder and the urinary bladder, before they are drained to the outside. Under normal conditions all excretory products remain in solution. Damage to the epithelium of the excretory canals or the reservoirs or changes in the composition of the secretions (because of abnormal intake or metabolic alterations) may lead to the precipitation of the metabolites in solution, causing obstructive masses called stones to be formed. 

Somatic pain responds well to NSAIDs and narcotics. Visceral pain, deep and poorly localized, caused by irritation of the serous or distension or ischemic tissue (for example pain associated with nephrolithiasis or pancreatitis) responds better to narcotics. In some cases, however, the narcotics themselves can exacerbate the problem (for example in case of bile duct obstruction). Neuropathic pain is characterized by excruciating burning pain, and is frequently associated with hypersensitivity. It maybe more responsive to anticonvulsants and antidepressants than to opioids. 

Acute pancreatitis occurs most commonly as a result of obstruction of the pancreatic duct. Diseases of the biliary tract and alcoholism are factors which can lead to this condition. The symptoms of acute pancreatitis include abdominal pain and shock and these are thought to be due to pancreatic enzymes in the abdominal cavity. The biochemical features of acute pancreatitis include raised serum levels of pancreatic enzymes (amylase being the one most commonly measured) and hypo-... 

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