Composition of gallstones in Coimbatore District of Tamil Nadu State

BACKGROUND: Gallstones in northern India are predominantly of the cholesterol type; such information on gallstones in southern India is scant. AIM: To analyze the composition of gallstones from patients residing in Coimbatore District in Tamil Nadu State. METHODS: The stones were classified using the Bernhoft criteria and was correlated with the morphological characteristics. RESULTS: Of the 105 gallstones analyzed, 67 (63.8%) were of the pigment variety and 36 (34.8%) of the intermediate/mixed type. There were only two cholesterol stones. The mean proportions of cholesterol, bilirubin and calcium in the pigment and intermediate stones were 7.1%, 26.1% and 7.8% and 30.2%, 18.4% and 6.3%, respectively. The mean proportion of bilirubin in the pigment stones was higher than in the intermediate type. Morphologically, pigment stones were black in 55% and amorphous in 63%; the intermediate stones were hard in 50% and of variegated color ranging from yellow to ivory white in 61%; both cholesterol stones were multiple, hard and brown. CONCLUSIONS: There is a predominance of pigment and intermediate gallstones (98%) in this district. These stones have reduced cholesterol and an increase in bilirubin and calcium proportions.