Teaching NeuroImages: Fahr syndrome caused by hypoparathyroidism.

A57-year-old woman with a remote history of thyroidectomy but no prior neurologic symptoms developed seizures, fever, and coma. Limited evaluation at her local hospital in rural Haiti demonstrated serum hypocalcemia (4 mg/dL) and extensive bilateral subcortical calcification in the cerebral and cerebellar hemispheres on CT (figure). This pattern of calcification can occur in inherited conditions such as familial idiopathic basal ganglia calcification (Fahr disease) and acquired conditions (referred to as Fahr syndrome) including parathyroid dysfunction and intrauterine infection. Given our patient’s severe hypocalcemia, Fahr syndrome was attributed to presumed hypoparathyroidism related to prior thyroidectomy in her case.