Statin-Induced Liver Injury Mimicking Autoimmune Hepatitis

Abstract

Introduction: HMG CoA reductase inhibitors (statins) are known to be a cause of hepatic dysfunction, with an incidence of transaminimitis from 0.5 to 3 percent, usually within the first 3 to 4 months of initiating therapy. Here we present a case of acute statin induced liver injury mimicking autoimmune hepatitis. Case Patient is a 70 year old male who initially presented with fatigue, scleral icterus, and a 50 pound weight loss over 3 months. Four months before, he had been started on atorvastatin 40 mg daily which was held on admission. Initial workup showed AST 113 IU/L, ALT 197 IU/L, alkaline phosphatase 944 IU/L (with elevated GGT), and total bilirubin 7.6 g/dL. His INR was 1.15 and creatinine and blood urea nitrogen were 9.53 mg/dL and 121 mg/dL, respectively (no preceding renal dysfunction). Viral hepatitis serologies were negative, and the patient denied any alcohol or acetaminophen use. An MRCP was negative for any biliary obstruction. Urinalysis showed granular casts consistent with acute tubular necrosis. He also had positive smooth muscle antibody, elevated IgG at 2458 mg/dL, positive ANA with 1:1280 titer in a speckled pattern, and positive C-ANCA with a 1:320 titer. P-ANCA, anti-glomerular basement membrane antibody, liver-kidney microsomal antibody, and anti-mitochondrial antibody were negative. Liver biopsy revealed mild mixed portal inflammation and reactive changes with portal fibrosis consistent with a drug reaction, without evidence of autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, or hypotensive changes. Kidney biopsy showed mild acute tubulointerstitial nephritis. His AST and ALT also normalized within 3 weeks, to 24 and 38 IU/L, respectively. His alkaline phosphatase improved more slowly, down to 476 IU/L within 3 weeks and total bilirubin improved to 1.3 g/dL. His renal function recovered with supportive care, with creatinine of 0.85 mg/dL within 3 weeks. At outpatient follow up 1 month later, the patient had already gained back 10 pounds, with no residual scleral icterus and improved fatigue. Discussion Statin-associated drug induced liver injury triggering autoimmune hepatitis is rare, with only ten such cases encountered in literature review. These reports often note a liver biopsy consistent with autoimmune hepatitis, which we did not observe. Most cases have required treatment with immunosuppressant medications, while our patient has so far recovered just by holding the statin medication.