pancreas diseases : Sphincter of Oddi dysfunction

SOD is a common cause of unexplained pancreatitis in patients seen in referral centres.[9] Endoscopic manometry can demonstrate separate biliary and pancreatic sphincters and there can be a discordance between the basal pressures in the two sphincters, with one normal and the other elevated. Silverman et al[10] reviewed the results of manometry in 111 patients with pancreaticobiliary pain, most of whom had normal liver and pancreatic chemistries. Manometry was possible in both sphincters in 88 (79%) patients; 28 (32%) patients had elevated pressure in both sphincters; and 15 (17%) patients demonstrated a discordance, with elevated pressure in one of the two sphincters. The clinical implication is that dual-sphincter manometry may be required when evaluating for unexplained pancreatitis and pancreatic sphincterotomy rather than biliary sphincterotomy may be required in some patients to relieve the pain.

A classification of pancreatitis-associated SOD has been proposed that is analogous to biliary SOD[11] : type I patients have recurrent attacks of pancreatitis (confirmed clinically and biochemically) with a dilated pancreatic duct and slow drainage. These patients appear to have stenotic lesions, do not require sphincter of Oddi manometry for diagnosis, and have the best results from sphincterotomy. Type II patients have acute relapsing pancreatitis and no evidence for stenosis other than tonic sphincter of Oddi pressures more than 40 mm Hg on manometric testing. Type III patients have pancreatic type of pain and no evidence of pancreatitis but an abnormal sphincter of Oddi manometry. Type III patients are least likely to respond to sphincterotomy. Pancreatic sphincterotomy should not be undertaken lightly because it is associated with a postprocedural pancreatitis in 11% of patients and a 14% restenosis rate.

by R BAIJAL