[Hypoparathyroidism and early onset dementia: Fahr syndrome should be suspected].

Fahr syndrome is a rare disorder, whose prevalence is lower than 0.5%. Clinical manifestations are variable ranging from mere behavioral disorders to tetany crises and severe neuropsychiatric manifestations. It may be idiopathic or secondary to numerous causes dominated by phosphocalcium metabolism disorders whose main cause is hypoparathyroidism. Positive diagnosis is based on radiology. We report the case of a 78-year old hypertensive female patient with a history of hypothyroidism, hypoparathyroidism after total thyroidectomy performed 30years before. She was treated with Levothyrox® 100 µg 2 capsules/day , One-Alpha® 1 μg 3 capsules/day and calperos® 2 capsules/day resulting in euthyroidia confirmed by clinical examination and laboratory tests and normal phosphocalcic test. Patient's outcome was marked, in 2010, by the development of rapidly worsening cognitive impairment and of early onset dementia in a few months. Neurological examination showed extrapyramidal syndrome. Cerebral CT scan showed large basal ganglia calcifications, white and gray linear substance near the junction, in the brain bulb and in the cerebellum. The diagnosis of Fahr syndrome, revealed by dementia occurred after a history of hypoparathyroidism, was then retained.