(See also Overview of Biliary Function.)
Biliary colic can occur in the absence of gallstones, particularly in young women. Acalculous biliary pain accounts for up to 15% of laparoscopic cholecystectomies. Common causes of such biliary pain include the following:
Microscopic stones—not detected by routine abdominal ultrasonography
Abnormal gallbladder emptying (gallbladder dyskinesia)
Biliary tract hypersensitivity
Sphincter of Oddi dysfunction (including stenosis and biliary dyskinesia )
Hypersensitivity of the adjacent duodenum
Gallstones that have spontaneously passed
The best diagnostic approach remains unclear.
Acalculous biliary pain is suspected in patients with biliary colic when diagnostic imaging cannot detect gallstones. Imaging should include ultrasonography and, where available, endoscopic ultrasonography (for small stones < 1 cm).
Abnormal laboratory tests may reveal evidence of a biliary tract abnormality (eg, elevated alkaline phosphatase, bilirubin, alanine aminotransferase, or aspartate aminotransferase) or a pancreatic abnormality (eg, elevated lipase) during an episode of acute pain. Cholescintigraphy with cholecystokinin infusion measures gallbladder emptying (ejection fraction); potentially interfering drugs such as calcium channel blockers, opioids, and anticholinergics should not be used. ERCP with biliary manometry detects sphincter of Oddi dysfunction.
Laparoscopic cholecystectomy improves outcomes for patients with microscopic stones and possibly abnormal gallbladder motility. Otherwise, the role of laparoscopic cholecystectomy or endoscopic sphincterotomy remains unclear. Drug therapies have no proven benefit.