Cardiology Fellow HCA Florida Orange Park Hospital Jacksonville, Florida, United States
Background: Thyroid storm is a rare, life-threatening medical emergency which may present as high-output heart failure (HF) with cardiogenic shock (CS). These cases can be challenging, as hemodynamics in such conditions are not well understood and initiation of mechanical circulatory support (MCS) is often delayed leading to grave outcomes.
Methods: Clinical
Case: A 49-year-old man with a history of untreated hyperthyroidism presented to the emergency room with atrial fibrillation (AF) with rapid ventricular rate (RVR) and concerns for new onset HF. Bedside echo showed biventricular HF with an ejection fraction of 29%, severe diffuse hypokinesis, and mitral regurgitation. A bedside Swan-Ganz catheter showed Fick cardiac index 7.1 L/min/m2 and mixed venous oxygen saturation of 84.4% which were consistent with high output HF. He was also found to have thyrotoxicosis with thyroid stimulating hormone < 0.01, elevated T4 4.23, free T3 211 and positive thyroid stimulating immunoglobulin. Burch-Wartofsky score on arrival was 55, highly suggestive of thyroid storm.
Outcome: Clinical Decision Making: The patient was initially managed with amiodarone and diuresis. Amiodarone was discontinued due to risk of precipitating further thyroid hormone synthesis. He was started on methimazole, steroids and cholestyramine to help achieve a euthyroid state. He became hypotensive, requiring pressor support and was intubated. In the setting of decreased SVR and tachyarrhythmia, norepinephrine was switched to phenylephrine. Esmolol drip and oral propranolol were used for beta blockade and to inhibit peripheral conversion of T4 to T3. Digoxin was used intermittently for rate control. Anticoagulation was contraindicated due to thrombocytopenia. He was trialed on intravenous immunoglobulin, and methimazole was switched to propylthiouracil, with transient improvement. However, he acutely decompensated and required increasing ventilatory and pressor support. Direct current cardioversion was performed with successful conversion to normal sinus rhythm; however, he soon reverted back to AF with RVR. Since he was in a refractory thyroid storm and continued to deteriorate due to acute respiratory distress syndrome and profound cardiogenic shock, the decision was made to transfer the patient to an ECMO center due to non-availability of ECMO care at our hospital. During the process the patient went into asystole and despite cardiopulmonary resuscitation attempts, the patient expired.
Conclusion: Thyroid storm creates a unique hemodynamic profile with decreased systemic vascular resistance, severe tachyarrhythmia and increased cardiac output. Management in such patients involves control of underlying tachyarrhythmia and antithyroid treatment. Due to rapid deterioration in such cases, early decision for MCS as a bridge to recovery can be pivotal.
