Abstract
Fosfomycin is an antibiotic often used to treat urinary tract infections
(UTIs) with only rare transient hepatotoxicity. We present a case of
fosfomycin-induced liver injury and describe the histopathologic
findings on biopsy. A 64 year-old female patient with no prior liver
disease or risk factors was started on fosfomycin as prophylaxis for
recurrent UTIs. Within a week of her first dose she presented with
fatigue, jaundice, and mixed liver enzyme elevation. Clinical workup for
acute liver injury was unremarkable, and biopsy showed panacinar and
portal necroinflammation with predominantly lymphocytic infiltrate and
cholestasis. This was thought to be likely related to fosfomycin
exposure. While liver enzymes trended down, bilirubin initially remained
elevated. However, within three months the patient achieved clinical and
biochemical recovery. Only two other reports of fosfomycin-induced liver
injury requiring biopsy were found. Both developed acute cholestatic
hepatitis within days of exposure, and subsequent biopsy similarly
showed lymphocytic necroinflammation. Although one patient initially
developed acute liver failure, both recovered fully within few months.
Overall, these cases suggest likely an idiosyncratic or immune-mediated
liver toxicity of fosfomycin which is typically self-limited with rapid
recovery. Liver biopsy may be useful in confirming the diagnosis.