Thyroid storm presenting as jaundice and complete heart block

Thyroid storm is a difficult diagnosis in "apathetic" variant of hyperthyroidism. The clinical features may not be evident. Abnormal atrioventricular (AV) conduction, such as complete heart block, in thyrotoxicosis is uncommon. We report a case of a 16-year-old girl presenting with fever, jaundice, heart failure and complete heart block in whom the diagnosis of thyroid storm was initially missed because of the unusual presenting features. Prompt resolution of the conduction abnormality occurred when treatment with carbimazole, intravenous iodide and dexamethasone was instituted.