[Hypocalcemia-induced heart failure as the initial symptom of hypoparathyroidism].

Hypocalcemia is a relatively uncommon reversible cause of congestive heart failure. There are a few reports of hypocalcemic children who developed congestive heart failure associated with hypoparathyroidism. In all these patients, however, cardiac failure did not occur before the age of nine years. In addition, other striking noncardial manifestations of hypoparathyroidism, e.g., convulsive seizures, had been present prior to cardiac symptoms. We report on a 3.7 year old girl with mitral insufficiency and severe cardiac failure due to hypocalcemia secondary to familial hypoparathyroidism. The infant's mother was suffering from idiopathic hypoparathyroidism, but her own history lacked any evidence for parathyroid hormone deficiency. On admission, she presented with fatigue, dyspnea, and pedal edema. Liver edge was palpable 4 cm below the right costal margin, and a 3/6 systolic murmur was heard. A chest x-ray showed cardiac enlargement; electrocardiogram demonstrated a prolonged QTc interval of 0.46 s. The echocardiography revealed a cleft in the mitral valve with mitral insufficiency and markedly reduced contractility of the left ventricle. Laboratory studies demonstrated a low total serum calcium level of 1.3 mmol/l; serum magnesium level was slightly decreased (0.5 mmol/l), and parathyroid hormone level was not detectable. Partial monosomy of chromosome 22 was excluded. Ophthalmological examination, audiometry, and renal ultrasonogram were normal. Oral calcium supplementation and anticongestive therapy with metildigoxin, furosemid, and captopril was initiated but no improvement of the heart failure occurred. However, normalization of serum calcium level by calcium infusions caused prompt clearing of the clinical symptoms, complete normalization of liver size, reduction of cardiac enlargement (thoracic ratio decreased from 0.68 to 0.57), and marked improvement in contractility (left ventricular shortening fraction increased from 21% to 34%). The QTc interval decreased to 0.39 s. The successful treatment following normalization of serum calcium level proved the superiority of hypocalcemia over mitral valve insufficiency in the etiology of the cardiac failure. To our knowledge, this is the first report of congestive heart failure due to hypocalcemia as the first manifestation of hypoparathyroidism in childhood. Hypocalcemia should be kept in mind in any congestive heart failure in children with or without underlying cardiac malformation.