Hyperthyroidism and Liver Dysfunction: A Review of a Common Comorbidity

Deranged liver enzymes due to hyperthyroidism rather than intrinsic liver pathology are not uncommon. The reported prevalence of liver biochemical abnormalities in patients with untreated thyrotoxicosis varies widely ranging from 15% to 76%. The suggested causes of liver dysfunction include direct hepatocyte injury, co-morbid heart failure, associated autoimmune conditions (especially in the setting of Graves' Disease), preexisting liver disease and drugs including antithyroid medications. Although, some patients may have a pattern of mild liver injury, about 1% to 2% can have fulminant hepatitis. Liver enzymes can return to normalcy in as many as 77% to 83% of patients once the initiations of thionamides are started in a timely fashion, which can help forestall complications and prevent or minimize multi-organ dysfunction. Clinicians should maintain a high index of suspicion for underlying hyperthyroidism in patients presenting with unexplained liver dysfunction or unexplained jaundice.