Isolated Primary Congenital Hypoparathyroidism Presenting as Recurrent Neonatal Hypocalcemic Seizures: A Case Report

Abstract

Aims: Congenital hypoparathyroidism is a rare cause of severe neonatal and early-infantile hypocalcaemia and may present with recurrent seizures. We report a case to highlight the importance of early metabolic evaluation in infants with unexplained recurrent seizures and to review the diagnostic approach to primary hypoparathyroidism. Presentation of Case: We report the case of a two-month-old male infant, born at 36 weeks of gestation, who was admitted after recurrent afebrile convulsive episodes first occurring on day 8 and again around day 30 of life. Severe hypocalcaemia had been documented previously but remained difficult to control. At 40 days of age, laboratory evaluation showed marked hypocalcaemia (61 mg/L), hyperphosphataemia (107 mg/L), and a low parathyroid hormone concentration (6 pg/mL), with normal magnesium, normal renal function, and no evidence of systemic inflammation or hypoglycaemia. Maternal calcium-phosphate metabolism was normal. Cardiac evaluation, electrocardiography, brain magnetic resonance imaging, and electroencephalography were unremarkable. Evaluation for a 22q11.2 deletion and selected chromosomal abnormalities was negative, while lymphocyte subsets and immunoglobulin levels were normal. Isolated primary congenital hypoparathyroidism was therefore diagnosed. Discussion: Treatment with intravenous and oral calcium and vitamin D therapy led to a favourable clinical course. The combination of severe hypocalcaemia, hyperphosphataemia, and an inappropriately low parathyroid hormone concentration in the setting of normal renal function and magnesium supports the diagnosis. This case emphasises the need to investigate congenital and syndromic causes of hypoparathyroidism in infants presenting with unexplained recurrent seizures. Conclusion: Congenital hypoparathyroidism should be considered in infants with recurrent or unexplained seizures, particularly when hypocalcaemia is severe or difficult to correct. Early biochemical evaluation (calcium, phosphate, magnesium, and parathyroid hormone) and investigation for syndromic and genetic causes can facilitate timely treatment and reduce the risk of recurrent hypocalcaemic seizures.