S5705 Acute Liver Injury Associated With Reishi Mushroom Supplementation in a Patient on Chronic Acetaminophen Therapy

Introduction: Reishi mushroom (Ganoderma lucidum) is a traditional Chinese medicinal herb used for promoting health and vitality. There are rare reports from Asia of clinically significant liver injury associated with its use. We present a unique case of acute liver injury in a patient with chronic acetaminophen use who recently started Reishi supplementation. Case Description/Methods: A 59-year-old woman was admitted with epigastric abdominal pain for a week. Initial labs: aspartate aminotransferase (AST) 557 U/L (0-32), alanine aminotransferase (ALT) 487 U/L (0-33), alkaline phosphatase 113 U/L (35-104), bilirubin 0.7 mg/dL (0-1.3), and lipase 226 IU/L (13-60). AST and ALT peaked at 798 and 1261, then declined to 29 and 227 U/L, respectively, in a week. Workup for Epstein Barr virus, cytomegalovirus, hepatitis viruses, and autoimmune markers was negative. Computed tomography (CT) abdomen showed surgically absent gallbladder and biliary dilation. Endoscopic ultrasound showed a diffusely dilated common bile duct without sludge or stones. Liver biopsy: The portal tracts showed mild inflammation with prominent eosinophils, no interface hepatitis. Bile ducts and vascular structures were intact. The hepatic parenchyma was unremarkable, without evidence of inflammation or necrosis. The patient reported chronic acetaminophen use (1,500 mg twice daily) for over a year for back and joint pain. She had also been taking a mushroom complex containing Reishi mushroom for approximately 1.5 months before admission, but stopped a few weeks prior. Alcohol consumption was occasional. Body mass index was 26, stable historically. Discussion: Reishi mushroom has been linked to rare hepatocellular injury, typically manifesting 1–2 months after initiation. Immune-allergic features are uncommon, and liver biopsies often indicate drug-induced injury rather than autoimmune hepatitis. Normal liver enzymes 9 months prior indicate an acute process in our patient. Given the chronic acetaminophen use and recent Reishi supplementation, the liver injury is suspected to be precipitated by the mushroom. Co-ingestion of Reishi and acetaminophen may have synergistically worsened hepatic injury in this patient with no underlying liver disease. Clinicians should be aware of its potential hepatotoxicity, especially in patients with other risk factors such as prolonged acetaminophen exposure or alcohol use. Early recognition and discontinuation of the offending agent are essential to prevent progression to severe liver damage. Further research is needed to better understand the mechanisms and risk factors underlying Reishi-related hepatotoxicity.