Histologic Characterization of Kratom Use-Associated Liver Injury

Kratom is an herbal product derived from the leaves of Southeast Asian Mitragyna speciosa trees. It has traditionally been used by indigenous people to relieve fatigue and manage pain, diarrhea, or opioid withdrawal. The use of kratom has become more commonplace in the United States for similar purposes. Only rare reports of kratom liver toxicity exist in the literature but without histologic characterization. Herein, we report one case of kratom use-associated liver toxicity in a 38-year-old patient. The patient complained of dark colored urine and light colored stools after using kratom. He had unremarkable physical examination. Laboratory testing at presentation revealed elevated alanine aminotransferase (389 U/L), aspartate aminotransferase (220 U/L), total bilirubin (5.1 mg/dL), and alkaline phosphatase (304 U/L). There was no serology evidence of viral hepatitis A, B, and C. The acetaminophen level at presentation was below detectable limits. Ultrasound examination of the right upper quadrant revealed normal echogenicity and contour of the liver without bile ductal dilatation or disease of the gallbladder. The patient underwent liver biopsy 4 days after the initial presentation which revealed a pattern of acute cholestatic liver injury including zone 3 hepatocellular and canalicular cholestasis, focal hepatocyte dropout, mild portal inflammation, and bile duct injury. Kratom was stopped, the patient improved clinically and biochemically and was discharged 8 days after the initial presentation. To our best knowledge, this is the first case report detailing the histology of kratom use-associated liver injury.