Cardiac Failure Secondary to Idiopathic Hypoparathyroidism: A Case Report

Hypoparathyroidism causes low calcium levels due to insufficient Parathyroid Hormone (PTH). This can lead to cardiovascular issues, including arrhythmias and rarely, hypocalcaemic cardiac failure. In cardiac failure, calcium dysregulation impairs contractility and increases myocardial stress. Hypoparathyroidism-induced hypocalcaemic cardiac failure is an exceptionally rare cause of heart failure, often unresponsive to standard treatments. This report highlights a case of a young female with undiagnosed idiopathic hypoparathyroidism who developed acute cardiac complications postoperatively after an appendectomy. Sixteen hours postsurgery, she experienced sudden onset breathlessness, with her oxygen saturation dropping to 50%. A chest X-ray showed bilateral homogeneous opacities consistent with pulmonary oedema. She was intubated, placed on invasive mechanical ventilation, and required pressor support before being transferred to the medicine unit. Initial Electrocardiography (ECG) findings were unremarkable. On the second day, carpal spasm was observed, prompting serum calcium testing, which revealed significantly low levels, as did serum PTH. Subsequent ECG demonstrated changes associated with hypocalcaemia, including a short PR interval and prolonged QT interval. Echocardiography indicated left ventricular hypokinesia with an ejection fraction of 25-30%, although cardiac enzymes were normal. N-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels were elevated, and arterial blood gas analysis showed metabolic alkalosis and hypokalemia. The hypocalcaemia was aggravated by metabolic alkalosis due to gastric drainage. A diagnosis of heart failure secondary to hypocalcaemia from idiopathic hypoparathyroidism was established after excluding other aetiologies. Treatment focusing on heart failure management and calcium correction led to significant clinical improvement, and the patient was successfully extubated. This case highlights the importance of measuring serum calcium in all patients presenting with heart failure, as hypocalcaemia is a treatable cause. A comprehensive evaluation of endocrine and metabolic factors is essential in young patients with unexplained heart failure for accurate diagnosis and effective management.