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Findings: The initial ultrasound of the gallbladder demonstrates multiple small shadowing gallstones within the dependent portion of the gallbladder. At a follow-up visit, all but a single gallstone remain within the gallbladder.
Diagnosis: Cholelithiasis complicating ceftriaxone therapy.
Discussion: Ceftriaxone, a third-generation cephalosporin, is commonly used for the treatment of a wide variety of bacterial infections in both the adult and pediatric patient populations. An unusual complication of long term therapy with this drug was first reported almost ten years ago by Schaad et al. Gallbladder precipitates were reported to develop in 3% of children treated for serious infections with ceftriaxone. These resolved spontaneously with cessation of therapy.
The primary route of excretion for ceftriaxone is renal. However, up to 40% of the drug may be excreted into bile, where the formation of calcium-ceftriaxone precipitates can take place. Thus the shadowing "stones" seen on ultrasound are actually precipitates of the antibiotic itself, leading some investigators to term this condition biliary pseudolithiasis. Further, with complete cessation of the antibiotic, spontaneous resolution of these "stones" is commonly seen, as in this case. This patient was treated with 1 gram/day of ceftriaxone for six weeks. Following the initial sonogram, the therapy was discontinued completely. It should be noted that with doses less than 1 g/day, precipitates have not been shown to occur.
References:
Schaad UB, Tschappeler H, Lentze MJ. Transient formation of
precipitations in the gallbladder associated with ceftriaxone
therapy. Pediatric Infectious Dis J, 1986; 5:708-710.
Kirejczyk WM, Crowe HM, Mackay IM, Quinitilliani R, Cronin EB.
Disappearing "Gallstones": Biliary Pseudolithiasis Complicating
Ceftriaxone Therapy. AJR 159:329-330, 1992.
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