Influenza A: Associated Severe Cholestatic Liver Injury in a Patient With Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD).

Influenza A infection typically causes mild hepatocellular liver enzyme elevations, while clinically significant cholestatic liver injury is rare. We report a case of severe intrahepatic cholestasis associated with Influenza A infection in a patient with pre-existing metabolic dysfunction-associated steatotic liver disease (MASLD). A 65-year-old female with MASLD and chronic prosthetic hip infection presented with confusion, hypoglycemia, and sepsis. One month prior, liver function tests were normal. On admission, laboratory evaluation demonstrated a cholestatic pattern with total bilirubin 3.6 mg/dL (direct 3.2 mg/dL), alkaline phosphatase (ALP) 300 U/L, and international normalized ratio (INR) 2.0. Rapid testing confirmed Influenza A infection. Imaging, including abdominal ultrasound and hepatobiliary iminodiacetic acid (HIDA) scan, showed a dilated common bile duct without obstruction but markedly impaired hepatic uptake and excretion. Despite biliary stenting, total bilirubin and ALP peaked at 8.5 mg/dL and 817 U/L. Liver biopsy revealed steatosis, lobular inflammation, cholestasis, and stage 2 fibrosis consistent with MASLD and superimposed acute cholestatic injury. With oseltamivir and supportive care, liver function tests gradually normalized. Influenza A may rarely precipitate severe intrahepatic cholestasis, particularly in patients with underlying steatotic liver disease.