Sweat chloride levels in fibrocystic disease of pancreas-
Ans. is 'a' i.e., Elevated * Fibrocystic disease of pancreas is the same as mucoviscoidosis i.e. Cystic fibrosis. In other words the question is referring to the levels of sweat chloride in patients with cystic fibrosis.Diagnosis of Cystic fibrosis* The diagnosis of CF rests on the combination of clinical criteria and abnormal CFTR function as documented by sweat tests, nasal PD measurements, and CFTR mutation analysis.* Elevated sweat Cl values are nearly pathognomonic for CF.* The sweat concentration values for CL (and Na+) vary with age, but, typically, a Cl concentration of >70 meq/L in adults discriminates between CF and other diseases.* DNA analysis of the most common mutations identify' CF mutations in >90% of affected patients.* The nasal PD measurement can document CFTR dysfunction if the sweat Cl" test is normal or borderline and two CF mutations are not identified.* DNA analysis is performed routinely in patients with CF, because pancreatic genotype-phenotype relationships have been identified and mutation class-specific treatments are being developed.Gastrointestinal effects of Cystic Fibrosis* The gastrointestinal effects of CF are diverse.* In the exocrine pancreas, the absence of the CFTR Cl- channel in the apical membrane of pancreatic ductal epithelia limits the function of an apical membrane Cl--HCO3- exchanger to secrete bicarbonate and Na+ (by a passive process) into the duct.* The failure to secrete Na+ HCO3- and water leads to retention of enzymes in the pancreas and destruction of virtually all pancreatic tissue.* Because of the lack of Cl- and water secretion, the CF intestinal epithelium fails to flush secreted mucins and other macromolecules from intestinal crypts.* The diminished CFTR-mediated liquid secretion may be exacerbated by excessive absorption of liquid, reflecting abnormalities of CFTR-mediated regulation of Na+ absorption (both mediated by Na+ channels and possibly other Na+ transporters, e.g., Na+-H+ exchangers).* Both dysfunctions lead to dehydrated intraluminal contents and intestinal obstruction.* In the hepatobiliary system, defective hepatic ductal salt (C1-) and water secretion causes thickened biliary secretions, focal biliary cirrhosis, and bile-duct proliferation in approximately 25-30% of patients with CF,* The inability of the CF gallbladder epithelium to secrete salt and water can lead to both chronic cholecystitis and cholelithiasis.
Elevated
Decreased
First elevated then decreased
First decreased then elevated
G.I.T.