Gallbladder stone recurrence after medical treatment. Do gallstones recur true to type?

Medical treatments that dissolve or remove gallbladder stones but leave the gallbladder in situ have the disadvantage of gallstone recurrence. Little is known about the composition of recurrent stones or whether they recur true to type. In 21 patients with recurrent stones detected 5-74 months (mean +/- SEM, 26 +/- 4 months) after being rendered stone-free with dissolution therapy (N = 15) or percutaneous cholecystolithotomy (N = 6), we compared pretreatment and postrecurrence gallstone number, maximum gallstone attenuation scores measured by computed tomography (CT) and, in 13, the dissolvability of the recurrent stones with oral bile acids +/- extracorporeal shock-wave lithotripsy. Before treatment, five patients had solitary and 16 had multiple stones but on recurrence, the gallstones differed in number from the primary stones in 10 of the 21 patients. As a result of patient selection, before dissolution, the primary stones were all radiolucent with maximum CT scores of < 100 Hounsfield units (HU) (mean 45, range 10-84 HU). On recurrence, the stones were again CT-lucent in 13 of the 15 patients but were CT-dense in the remaining two (118 and 176 HU). Initially, all six patients treated by percutaneous cholecystolithotomy had radio-opaque stones, with a mean CT score of 459 (range 100-969) HU. However, on recurrence, only one had calcified stones (HU 140); the remaining five had CT-lucent stones (16-98 HU, P < 0.05). Of the 13 patients whose recurrent, plain x-ray-lucent and CT-lucent stones were treated with oral bile acids +/- lithotripsy, 12 (92%) showed evidence of gallstone dissolution. We conclude that gallbladder stones do not recur true to type in up to two thirds of patients. However, irrespective of original gallstone composition, recurrent stones are usually radio- and CT-lucent, presumed cholesterol-rich, and therefore potentially dissolvable with oral bile acids.