Gone (From the Physicians' Desk Reference) But Not Forgotten: Propylthiouracil-Associated Hepatic Failure: A Call for Liver Test Monitoring

A 19-year-old female diagnosed with Graves' disease had treatment initiated with propylthiouracil (PTU). Pretreatment complete blood count and liver-associated enzymes (LAEs) were normal, but no further LAEs were obtained, reflecting US guidelines written in 1995. Three months later, she presented with nausea, vomiting, abdominal pain, and jaundice. LAEs were markedly elevated with: total bilirubin, 6.5 mg/ dl; aspartate aminotransferase (AST), 1747 IU/L; and alanine aminotransferase (ALT) 1589 UL/L. After 6 days at an outside hospital, she was transferred to our tertiary care center in acute liver failure with coagulopathy and stage II encephalopathy. Liver transplant evaluation was promptly initiated and she was listed as status 1. PTU was the only medication she had taken; and all serologic, autoimmune, and metabolic studies were negative. She demonstrated rapid clinical deterioration, and on hospital day 7 she underwent orthotopic liver transplant but succumbed to tonsillar herniation immediately after surgery. Pathology from her explanted liver revealed marked necrosis and collapse, consistent with her acute liver failure. PTU-associated hepatotoxicity and myelotoxicity have been well-recognized serious adverse effects for more than 50 years. However, as deaths related to hepatic injury from PTU are rare, American Thyroid Association guidelines do not call for routine monitoring of LAEs, although monitoring of white blood cell count levels is advised. Given the wide spectrum of PTU-related liver injury, ranging from asymptomatic elevations in ALT to fatal acute liver failure, we urge consideration of an LAE monitoring program to prevent irreversible liver damage and call for a reappraisal of monitoring guidelines in the United States.