UNCOMMON CAUSE OF COMPLETE ATRIOVENTRICULAR BLOCK PRESENTING WITH DYSPNEA

Abstract

SESSION TITLE: Wednesday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Myxedema coma is defined as severe hypothyroidism leading to decreased mental status, hypothermia, hypotension, bradycardia, hyponatremia, hypoglycemia, hypoventilation and other symptoms related to slowing of function in multiple organs. Severe hypothyroidism is associated with bradycardia, decreased myocardial contractility, a low cardiac output, hypotension however, ventricular function is rarely compromised. Atrioventricular (AV) block is defined as a delay or interruption in the transmission of an impulse from the atria to the ventricles due to an anatomical or functional impairment in the conduction system. The conduction disturbance can be transient or permanent, with conduction that is delayed, intermittent, or absent. In the third degree, complete AV block, no atrial impulses reach the ventricle. We present a case with the uncommon manifestation of complete AV block secondary to myxedema coma. CASE PRESENTATION: A 66-year-old man with no past medical history and no medical follow up presented to our urgency room complaining of dyspnea at rest, lightheadedness, reduced exercise tolerance that was getting worse since 1 moth prior to seek for medical help. On physical examination he had altered mental status with vital sign with BP in 92/56mmHg, heart rate of 35 beats per minute, temperature of 35 Celsius degrees, respiratory rate of 12 per minute. He is obese, bald and dry skin. His electrocardiogram (ECG) showed evidence of complete heart block. Labs remarkable for a thyroid stimulating hormone of greater than 100 mIU/L. No other apparent cause for AV block. DISCUSSION: Due to hypoventilation patient developed a hypercapnic respiratory failure that required endotracheal intubation ad mechanical ventilation. He was admitted to intensive care unit and placed on a transvenous pacemaker. After the treatment with intravenous levothyroxine for 6 days patient was successfully extubated, and the ECG returned to normal sinus rhythm without any other treatment. The transvenous pacemaker was discontinued and transitioned to oral levothyroxine. He was successfully treated and discharged home with complete resolution of symptoms. CONCLUSIONS: This case showed an uncommon and reversible cause of complete AV block secondary to severe hypothyroidism. With adequate recognition and treatment, we successfully treat this condition with high morbidity and mortality if not treated. The AV block was completely resolved with the thyroid hormone replacement. Reference #1: Kwaku MP, Burman KD. Myxedema coma. J Intensive Care Med 2007; 22:224. DISCLOSURES: No relevant relationships by Marlene Farinacci Vilaro, source=Web Response No relevant relationships by Ricardo Fernandez, source=Web Response No relevant relationships by Luis Gerena Montano, source=Web Response