Fahr syndrome associated with hypoparathyroidism: Case report

Fahr's syndrome is characterized by bilateral intracranial calcifications involving the cerebellum, basal ganglia, thalamus, radial crown, and subcortical white matter. It is a rare neurological disorder often associated with hypoparathyroidism (HypoPT). HypoPT-induced hypocalcemia triggers calcium-phosphate deposition in brain parenchyma, typically manifesting as tetany, seizures, or extrapyramidal symptoms. Diagnostic challenges arise from overlapping symptom features with neurodegenerative and psychiatric disorders. We present a case of Fahr's syndrome secondary to iatrogenic HypoPT, highlighting pitfalls in long-term misdiagnosis.

A 58-year-old female presented with progressive rigidity, resting tremor, and recurrent tetanic spasms for 2 years. She had undergone neck surgery 18 years ago and had a 15-year diagnosis of epilepsy.

During hospitalization, her laboratory results indicated significant hypocalcemia, accompanied by extensive intracranial calcification on head computed tomography. Combining her symptoms, signs, and test results, we finally diagnosed her with Fahr's syndrome associated with HypoPT.

The patient received intravenous calcium gluconate (1 g/day) and oral 0.5 μg calcitriol with 600 mg calcium carbonate twice daily.

Serum calcium normalized within two weeks, with resolution of tetany and creatine kinase reduction to 210 U/L. In addition, the patient's symptoms, such as rigidity and tremor of extremities, along with bradykinesia, also got relieved by the correction of calcium.

For neurologists, when encountering patients presenting with clinical seizures or movement disorders, prompt head computed tomography scans and assessments of serum calcium, phosphorus, and parathyroid hormone levels are crucial to facilitate early diagnosis.