Purpose. Ceftriaxone is known to induce reversible precipitations, known as pseudolithiasis, in the gallbladder and urinary tract. The aim of this study was to investigate the incidence and predisposing factors that contribute to this side effect. Methods. A prospective study was conducted in 156 children admitted for the treatment of various infections with different daily ceftriaxone doses (50 mg/kg, 75 mg/kg, and 100 mg/kg). Sonographic examinations of the gallbladder and urinary tract were performed before treatment on the third and seventh day of therapy, and at the first and second month after the end of treatment. Patients with positive findings were followed with weekly sonographic examinations until the abnormality resolved. Results. Abnormal gallbladder sonograms were demonstrated in 27 children (17%); 16 of them (10%) had gallbladder lithiasis, 11 had gallbladder sludge (7%) (n = 4 on the third day, n = 23 on the seventh day), and 1 developed urolithiasis (0.6%). Five children (19%) were symptomatic. The abnormalities resolved after a mean of 16 days (range 10-30 days). Patients with pseudolithiasis were older and treated with higher drug doses than those with normal sonographic findings (P< 0.01 and P< 0.05, respectively). Conclusions. Biliary pseudolithiasis (and infrequently nephrolithiasis) usually occurs in children receiving high doses of ceftriaxone. It is generally asymptomatic. When this reversible complication becomes symptomatic, unnecessary cholecystectomy should be avoided. (C) 2006 Wiley Periodicals, Inc.
