Fahr's syndrome in a patient with unknown hypoparathyroidism
Joana Nicolau Ramis, Anna Espino Ibáñez, Carla Francés Artigas, Rosmeri Rivera Irigoin, Josefina Olivares Alcolea, Luis Alberto Gómez Gómez, Irene Rodríguez Rodríguez & Lluis Masmiquel Comas
Introduction: Fahrs syndrome in characterized by bilateral calcifications in basal ganglia, dentate nucleus and semioval center. Its clinical manifestations are a rigid hypokinetic syndrome, mood disorders and cognitive impairment. The most frequent aetiology of this syndrome is, together with idiopatic causes and congenital infections, calcium disorders, mainly primary hypoparathyroidism, accounting for up to 80% of all causes.
Case report: A 57-year-old woman was admitted to the Neurology Unit for study of parkinsonian features that had worsened over the last 6 months. She had a medical history of dyslipidemia, 6-year-history of depressive syndrome. She reported no family history of interest. She related a progressive 6-month self-limiting walking disorder along with cramps and stiffness in lower limbs. On physical exam, the most important findings were: cogwheel rigidity and absence of reflexes; Chvostek and Trousseau signs were positive. Laboratory findings were: calcium 3.8 mg/dl (reference range 8.410.5 mg/dl), phosphorus 6.8 mg/dl (2.54.5 mg/dl), CK 693 IU/l (20135), 25-OH vitamin D 32 ng/ml (2054), PTH 6.3 pg/ml (1179.5), calcium urine 81.4 mg/24 h (100300). The electromyogram showed spontaneous and continuous muscular activity in lower limbs. CT scan showed diffuse, symmetric parenchymal calcifications involving the dentate nuclei, basal ganglia and deep cerebral white matter. All these findings were ascribed to Fahrs syndrome due to a primary hypoparathyroidism. The patient was treated with intravenous calcium and after restoring normal plasmatic levels she continued with 1000 mg calcium carbonate orally and 0.5 μg/day calcitriol, maintaining normocalcemia. Other endocrine disorders were excluded as well as Huntingtons disease and viral infections. Calcium sensing receptor and antiparathyroid tissue antibodies were also negative. Chvostek and Trousseau became negative. Stiffness and cramps disappeared and electromyogram became normal; however, no changes in walking were seen. Six months later, the patient continued normocalcemic. No improvements in parkinsonian walking were seen despite normocalcemia and treatment with levodopa.
Conclusions: Primary hypoparathyroidism should be ruled out when diagnosing a Fahrs syndrome. Restoring normocalcemia improves cramps and myoclonus; however, it has little effect on mood or parkinsonism.