Myxedema Heart Disease in a Teenage Child

Myxedema heart disease is an exceptionally rare condition with few reported cases. We present a rare case of a child who presented with severe congestive heart failure secondary to myxedema heart disease complicated by preexisting valvular heart disease. The patient was admitted to the pediatric intensive care unit and medical management. An echocardiogram showed severe biventricular dysfunction and severe valvular disease. She was started on levothyroxine and liothyronine. During the patient's hospitalization, the thyroxine level normalized but the thyroid-stimulating hormone continued to remain elevated. Likewise, her cardiac ventricular function improved, though it did not return to baseline. Our case highlights the importance of maintaining a broad differential diagnosis in a child who presents with congestive heart failure, to include thyroid disease, which necessitates a rare but specific management strategy.