Is Hypocalcaemia Secondary to Iatrogenic Hypoparathyroidism a Possible Cause of Dilated Cardiomyopathy? A Case of Reversible Hypocalcemia-induced Cardiomyopathy

Abstract

Dilated cardiomyopathy (DCM) is a heterogeneous myocardial disorder frequently linked to ischemic, hypertensive, or idiopathic etiologies. However, metabolic causes such as hypocalcemia, though rare, can lead to reversible myocardial dysfunction. Hypocalcemia-induced cardiomyopathy (HIC), particularly secondary to iatrogenic hypoparathyroidism, is an underrecognized but treatable condition. We report the case of a 51-year-old woman with a history of breast and thyroid cancer, who developed recurrent symptomatic hypocalcemia following total thyroidectomy, consistent with iatrogenic hypoparathyroidism. She presented with paresthesias, muscle cramps, and positive Chvostek and Trousseau signs, repeatedly requiring hospitalizations. Her poor adherence to calcium and vitamin D therapy was identified as the main cause of recurrent hypocalcemic episodes. She was admitted for decompensated heart failure with a left ventricular ejection fraction (LVEF) of 25%. Cardiac MRI excluded ischemic, valvular, or toxic causes of cardiomyopathy. Severe hypocalcemia (serum calcium 54 mg/L) was again noted during admission. Following intravenous calcium replacement and optimized oral supplementation, her LVEF improved to 55% at three months, confirming the diagnosis of HIC.Hypocalcemia should be considered in the differential diagnosis of unexplained DCM, especially in patients with a history of thyroidectomy. The pathophysiology involves impaired myocardial excitation-contraction coupling due to calcium deficiency. If recognized early, HIC has an excellent prognosis with normalization of cardiac function upon calcium correction. This case underscores the importance of identifying reversible metabolic causes of DCM. Hypocalcemia secondary to hypoparathyroidism, although rare, should not be overlooked, particularly in non-compliant patients. Prompt recognition and correction of calcium levels can lead to full recovery of cardiac function.