Controversies concerning pathophysiology and management of acalculous biliary-type abdominal pain.

Acalculous biliary-type abdominal pain is a commonly encountered clinical problem whose pathophysiology is unclear and evaluation and management are controversial. Cholecystokinin cholescintigraphy to measure the gallbladder ejection fraction (GEF) has been advocated as a criterion for cholecystectomy. However, there is no consensus regarding the dose and rate of infusion of cholecystokinin, both of which can alter the GEF, and the definition of an abnormal ejection fraction varies among studies. Many but not all studies have concluded that a low GEF predicts good outcomes after cholecystectomy, but most studies suffer from poor methodology and there is only one prospective randomized controlled trial. Also, some patients with a normal GEF have responded to cholecystectomy. Another controversial area has been the role of sphincter of Oddi dysfunction (SOD) in patients with biliary-type pain and gallbladder in situ. Some reports suggest an overlap between SOD and low GEF, although a causal relationship has not been established. Yet another subject of interest is the role of visceral hyperalgesia in patients with acalculous biliary-type pain. We have reviewed the relevant literature relating to these issues and have highlighted the controversial aspects. In the absence of high-quality studies, an evidence-based treatment algorithm is difficult to design but will be proposed. More prospective controlled trials are warranted to better define the appropriate evaluation and management of patients with this syndrome.