Courvoisier's gallbladder: law or sign?

BACKGROUND: Variously described as Courvoisier's law, sign, or even gallbladder, this eponymous "law" has been taught to medical students since the publication of Courvoisier's treatise in 1890.
METHODS: We reviewed Courvoisier's original "law," the modern misconceptions surrounding it, and the contemporary evidence supporting and explaining his observations.
RESULTS: Courvoisier never stated a "law" in the context of a jaundiced patient with a palpable gallbladder. He described 187 cases of common bile duct obstruction, observing that gallbladder dilatation seldom occurred with stone obstruction of the bile duct. The classic explanation for Courvoisier's finding is based on the underlying pathologic process. With the presence of gallstones come repeated episodes of infection and subsequent fibrosis of the gallbladder. In the event that a gallstone causes the obstruction, the gallbladder is shrunken owing to fibrosis and is unlikely to be distensible and, hence, palpable. With other causes of obstruction, the gallbladder distends as a result of the back-pressure from obstructed bile flow. However, recent experiments show that gallbladders are equally distensible in vitro, irrespective of the pathology, suggesting that chronicity of the obstruction is the key. Chronically elevated intraductal pressures are more likely to develop with malignant obstruction owing to the progressive nature of the disease. Gallstones cause obstruction in an intermittent fashion, which is generally not consistent enough to produce such a chronic rise in pressure.
CONCLUSION: We hope that reminding clinicians of Courvoisier's actual observations will reestablish the usefulness of this clinical sign in the way he intended.