The circadian rhythm of biliary colic.

We evaluated 50 consecutive patients with symptomatic gallstones for the clinical features of biliary pain with particular reference to the timing of their painful episodes. Thirty-eight of the 50 patients were able to provide the time of onset of biliary pain in the 24-h cycle. The time of onset of biliary pain displays significant circadian periodicity (p = 0.0032), with its peak at 00:25 h. Forty-five patients had more than 1 episode of pain. Of these 84% had either all or over half of their attacks of biliary pain at the same clock time. Twenty-two patients with renal colic (a close parallel to biliary pain) and 31 patients with episodic abdominal pain from miscellaneous causes showed no circadian or other periodicity in the time of onset of pain. In only 1 of these patients did the abdominal pain recur consistently at the same clock time. "Typical" biliary pain has its onset at night and tends to recur at the same clock time. It is steady and relatively mild, lasting 1-5 h, it is felt in the right upper quadrant or the epigastrium, may radiate to a variety of sites, is associated with some additional symptoms, and is not usually related to meals. The chronobiological and other features of biliary pain reported here should be useful in the diagnostic evaluation of abdominal pain.