Mood disorder as a manifestation of primary hypoparathyroidism: a case report

Primary hypoparathyroidism is a rare condition caused by parathyroid hormone deficiency and characterized by hypocalcemia. The clinical manifestations of primary hypoparathyroidism include tetany, seizures, paresthesias, dementia, and parkinsonism. Psychiatric manifestations such as mood disorders are unusual and may constitute a major diagnostic challenge, especially if the typical manifestations caused by hypocalcemia are absent.

The patient was a 22-year-old Caucasian man with a history of chronic omeprazole use and periodic seizures, who presented to the emergency department of a secondary hospital in Southern Brazil with symptoms of major depression (sadness, anhedonia, loss of appetite, insomnia, and fatigue) associated with paresthesias affecting his toes. The initial electrocardiogram revealed a prolonged QTc interval. A computed tomography scan of his brain revealed bilateral, nonenhancing hyperdense calcifications involving the putamen and caudate nucleus. An electroencephalogram showed generalized bursts of slow spikes. Blood laboratory study results indicated serum hypocalcemia, hypomagnesemia, and hyperphosphatemia associated with a low parathyroid hormone level. His serum levels of albumin, 25-hydroxyvitamin D, thyroid-stimulating hormone, T3 and T4 thyroid hormones, as well as the results of kidney function tests, were normal. The definitive diagnosis was primary hypoparathyroidism with psychiatric manifestations due to chronic hypomagnesemia induced by proton pump inhibitor use.

In some cases, to differentiate between a primary psychiatric disorder and primary hypoparathyroidism with neuropsychiatric symptoms may represent a challenge given that the classical manifestations of hypocalcemia, especially tetany, may be absent in the setting of chronic hypoparathyroidism. Clinicians and psychiatrists should consider primary hypoparathyroidism part of the differential diagnosis during the evaluation of patients with mood symptoms, especially in the context of atypical presentations associated with hypocalcemia.