How often are Ghananian gallbladder stones cholesterol-rich

Although the prevalence of symptomatic gallbladder stone disease in Ghana increased almost four-fold between 1966 and 1991, little is known about the composition of and aetiopathogenesis of these stones, nor about their suitability for non-surgical (dissolution) treatments.

To study this, gallstones from 67 out of 90 patients coming to cholecystectomy were retrieved and, based on their external appearance, classified provisionally as cholesterol(chol) (n = 8), black pigment (n = 28) and brown pigment (n = 31) stones. The gallstones were then homogenised, their cholesterol(chol) content measured chemically and the stones re-classified as cholesterol-poor (< 10% chol by weight), intermediate (10-75% chol) and cholesterol-rich (> 75% chol). The relationship between the initial and the definitive classifications was then examined and the biliary bacteriology (carried out on fresh samples of gallbladder(GB) bile obtained by fine needle aspiration) on gallstone composition, analysed.

The external appearance correctly predicted stone composition in the 28 thought, initially, to have black pigment stones (all of whom had stones containing < 10% chol by weight, on chemical analysis) and the eight believed, originally to have "cholesterol" stones (all of whom had stones with > 75% chol) but it proved unreliable in the 31 considered, at the time of surgery, to have brown pigment stones (mean chol content 58+ SEM 35%; range 0-98%. By chemical analysis, more than half the patients 35 of 67 or 52% had cholesterol-poor stones, nine (13% of the total) had intermediate stones, while 23 (34%) had cholesterol-rich stones. Cholesterol-rich gallstones were also more frequent in women than in men (p < 0.03). Only nine of 43 patients (21%) whose GB bile was aspirated, had positive bacterial cultures. There was no obvious difference in stone composition between those with positive, and those with negative, cultures.

Since the majority of Ghanaian patients with cholecystolithiasis have gallbladder stones with < 75% chol by weight, when active treatment is indicated surgery is more appropriate than dissolution therapy. However contrary to common belief, cholesterol-rich gallstones do occur in West Africa: 34% of the present series had stones with > 70% chol by weight.