Case Presentation: A 61-year-old male with a medical history of biliary dyskinesia status post cholecystectomy 3 months prior, presented to the hospital with right upper quadrant abdominal pain and outpatient imaging concerning for possible bile leak. The pain was intermittent, occurring several times per week and started after his cholecystectomy. The pain was absent during our initial evaluation. On presentation his vitals were normal, physical exam was benign, and labs were unremarkable. MRCP and HIDA scan were negative for bile leak, retained stones, obvious pancreatic or biliary malignancy, and dilated bile duct. On hospital day 2 he experienced an episode of severe abdominal pain, and labs collected concurrently showed an acute rise of his ALT/AST to 342/421. This acute episode of pain followed by a sharp elevation in liver function tests (LFTs) was concerning for type 1 sphincter of Oddi dysfunction (SOD). Endoscopic retrograde cholangiopancreatography (ERCP) supported findings of dilated common bile duct, and patient underwent a sphincterotomy for empiric treatment. The patient had relief from his abdominal pain and was subsequently discharged.
Discussion: Sphincter of Oddi dysfunction is a rare cause of abdominal pain, that hospitalists should keep in mind, when evaluating patients with chronic abdominal pain after a cholecystectomy. SOD is caused by stenosis or dyskinesia of the sphincter of Oddi (SO) which prevents it from properly relaxing (Current). Classically, SOD was divided into three types based off the Milwaukee Classification, however, these definitions have since come into question. SOD types II and III are largely believed to be functional disorders while type I SOD is believed to be caused by organic stenosis (Cotton). Type I SOD is defined as the presence of both a dilated biliary duct on imaging and abnormal liver function tests. While diagnosis may be assisted by HIDA scans and MRCP the gold standard for diagnosis is ERCP with manometry, however, this is rarely done. Manometry is often technically challenging and not widely available. Therefore, when clinical suspicion for SOD is high, current guidelines support treatment with empiric sphincterotomy. While treatment for SOD is controversial, most sources agree that empiric sphincterotomy for type I SOD is beneficial (Cotton).
Conclusions: This case highlights the importance of maintaining a broad differential in patients with chronic abdominal pain post-cholecystectomy with elevated liver function tests. Of the 10-20% of patients who have post-cholecystectomy syndrome, Sphincter of Oddi Dysfunction occurs in 1.5% of patients (Black). If SOD is suspected, hospitalists must work with their gastroenterology colleagues, to arrange further investigation and definitive treatment with ERCP. SOD is a challenging diagnosis to make but recognizing it can improve chronic abdominal pain in these patients.
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