Cardiovascular Collapse Secondary to Beta-Blocker Administration in a Setting of Coexisting Thyroid Storm and Atrial Fibrillation: A Case Report

A thyroid storm is a rare endocrinological emergency caused by severe hyperthyroidism. Reducing circulating levels of free T3 in blood and beta-adrenergic inhibition are the basis of medical treatment for thyroid storms. Propranolol, due to its additional effect of preventing the peripheral conversion of dormant T4 to active form T3, is the chosen drug for blockade in hyperthyroidism and thyroid storm. We describe a rare clinical case of cardiovascular collapse following propranolol administration in a setting of thyroid storm. The patient presented with symptoms of dyspnea and palpitations and had an ejection fraction of 10%. He was started on a calcium channel blocker (diltiazem). Further investigations revealed that the patient also had a thyroid storm and was immediately shifted to methimazole and propranolol. However, following the administration of a beta-blocker, the patient developed circulatory failure as a result of cardiac arrest, necessitating the use of vasopressors and inotropes. This implores the need for further investigations and treatment regimens for cardiovascular conditions, especially atrial fibrillation arising in thyrotoxicosis, as there are no solid treatment guides in the literature to the best of our knowledge.