Prevalence of Silent Gallstones on Ultrasound in a Nigerian Population

Gallstones detected incidentally during imaging are termed 'silent' or asymptomatic gallstones and they account for 80% of all gallstones. About 1-2% of patients with silent gallstones develop symptoms yearly; however, determining those who will develop symptoms is a major challenge. Ultrasonography is the most sensitive and specific method of detecting gallstones with an accuracy greater than 95%. The study aims to determine the prevalence of ultrasound-diagnosed silent gallstones in a Nigerian population and to determine its association with age and gender.

This was a retrospective analysis of abdominal ultrasound scans performed at the Radiology department of a tertiary institution between January 2013 and December 2015. Data retrieved included age, sex, and sonographic findings. Data analysis was done by simple proportions and percentages using the Statistical Package for Social Sciences version 20.0 software.

Two thousand, one hundred and thirty-eight patients had abdominal ultrasound scans for various reasons during the study period. These included 915 males and 1223 females. Incidental findings of gallstones were observed in 52 patients, giving a prevalence of 2.4%. The prevalence of gallstones increased with age (p=0.051) with the highest prevalence seen in the 5th decade. Gallstones prevalence was higher in females with a male-to-female ratio of 1:3.5.

The prevalence of silent gallstones is low in our environment, but given the complications that may arise, follow-up for early detection of complications in the patients is therefore strongly recommended.