Clinical significance of the tests used in the diagnosis of pancreatic diseases

: Different methods available for investigating patients for pancreatic disease are discussed. They first include measurement of pancreatic enzymes in biological fluids. Basal amylase and/or lipase in blood are truly diagnostic in acute pancreatitis but their utility is low in chronic pancreatic diseases. Evocative tests have been performed to increase the sensitivity of blood enzyme measurement. The procedure is based on enzyme determination following administration of pancreozymin and secretin, and offers a valuable aid in diagnosis of chronic pancreatitis and cancer of the pancreas. They are capable of discerning pancreatic lesions but are not really discriminatory because similar changes are observed in both diseases. The measurement of urinary enzyme levels in patients with acute pancreatitis is a sensitive indicator of disease. The urinary amylase excretion rises to abnormal levels and persists at significant values for a longer period of time than the serum amylase in acute pancreatitis. The fractional urinary amylase escretion seems to be more sensitive than daily urinary measurement. The pancreatic exocrin function can be assessed by examining the duodenal contents after intravenous administration of pancreozymin and secretin. Different abnormal secretory patterns can be determinated. Total secretory deficiency is observed in patients with obstruction of excretory ducts by tumors of the head of the pancreas and in the end stage of chronic pancreatitis. Low volume with normal bicarbonate and enzyme concentration is another typical pattern seen in neoplastic obstruction of escretory ducts. In chronic pancreatitis the chief defect is the inability of the gland to secrete a juice with a high bicarbonate concentration; but in the advanced stage diminution of enzyme and volume is also evident. Diagnostic procedures for pancreatic diseases include digestion and absorption tests. The microscopic examination and chemical estimation of the fats in stool specimens in different conditions of intake are still important screening tests. Isotopic estimates of steatorrhea and distinction between labeled triolein and oleic acid absorption do not provide greater diagnostic discrimination than traditional procedures. 131I labeled proteins permit a good evaluation of a negative nitrogen balance. Sophisticated procedures to estimate exocrine pancreatic insufficiency are based on the study of endoluminal digestive processes at several times and different level of the small intestine. They permite esclusion of extrapancreatic factors interfering in digestion and absorption functions. The endocrin pancreatic function is evaluated by mean of oral tolerance test an radioimmunoassay of blood insulin. It is generally agreed that "diabetes" caused by insulin deficiency and digestion and absorption defects are the result of diffuse pancreatic destruction. Many methods are now available investigating patients with pancreatic disease but the single use of one of them is never satisfactory...