Découverte fortuite d’un syndrome de Fahr suite à une crise convulsive

Abstract

Le syndrome de Fahr associe des calcifications intracérébrales, non artério-sclérotiques, bilatérales et symétriques à des perturbations métaboliques phosphocalciques. Il doit être distingué de la maladie de Fahr. Les manifestations cliniques sont diverses et comportent en premier lieu des signes neuropsychiatriques mais qui ne correspondent souvent à aucun tableau spécifique. L’examen diagnostique de choix est la tomodensitométrie cérébrale.Nous rapportons les observations de deux enfants ayant un syndrome de Fahr, l’un révélé par des troubles neuropsychiatriques et cognitifs et l’autre par une épilepsie associée à des symptômes neuropsychiatriques. Dans les deux cas, l’imagerie cérébrale et les examens biologiques ont permis de poser le diagnostic. L’évolution, dans les deux cas, a été favorable sous vitamino-calcithérapie associée au traitement substitutif de l’hypothyroïdie dans le premier cas et au traitement antiépileptique dans le deuxième cas.Le syndrome de Fahr est une entité rare. Les anomalies du métabolisme phosphocalcique et les calcifications cérébrales doivent être recherchées en présence de troubles neuropsychiatriques afin d’adopter les mesures thérapeutiques appropriées.Fahr's syndrome is a rare anatomo-clinical entity, defined radiologically by the presence of bilateral, symmetric and non-arteriosclerotic triatopallidodentate calcifications. It should be distinguished from Fahr's disease, which corresponds to calcifications of the basal ganglia without phosphocalcic metabolism abnormalities. Fahr's syndrome is generally difficult to suspect clinically because symptoms are not specific. These are usually neuropsychiatric disorders with changes in personality and behavior, confusion or delirium. Other neurological manifestations include cognitive impairment, intellectual deterioration, mental disability, extrapyramidal involvement, and more rarely pyramidal syndrome, cerebellar syndrome and intracranial hypertension. Fahr's syndrome occurs predominantly in patients with dysparathyroidism, notably hypoparathyroidism. Computed tomography is the preferable method of localizing and assessing the intracerebral calcifications. We report two pediatric cases of Fahr syndrome illustrating the importance of neuro-imaging and the search for disrupted phosphocalcic metabolism in children with neuropsychiatric disorders.Case 1 A 13-year-old boy presented to our outpatient department for academic difficulties and personality disorders such as anxiety and irritability. His past medical history includes delayed language development and several surgical ablations of subcutaneous nodules. Clinical examination showed surgical scars, subcutaneous calcinosis, statural delay and dysmorphic facial features: moon facies, depressed nasal bridge, hypertelorism, short neck and brachydactylie of the fourth finger. CT (computed tomography) scan of the brain revealed symmetrical calcifications in the cerebellar hemispheres, central gray nuclei and subcortical white matter. Laboratory tests revealed hypocalcemia, hyperphosphatemia, high level of parathyroid hormone and hypothyroidism. The diagnosis of Fahr's syndrome revealing pseudohypoparathyroidism was made. Subsequently, a treatment with calcium and 1-alpha-hydroxy-vitamin D was started.Case 2: A 5 years 6 months old boy was referred to the hospital with a history of generalized tonic-clonic seizures partially controlled with Sodium Valproate. His parents reported neuropsychiatric disorders such as memory disturbances, irritability, anxiety, intellectual deterioration and transient dysarthria. The neurological examination revealed psychomotor slowing and ataxia. Electroencephalogram showed bilateral temporal epileptiform activity. Laboratory tests revealed hypocalcaemia, hyperphosphatemia and decreased levels of parathormone. CT scan of brain showed bilateral and symmetrical calcifications in the palidum, striatum, thalamus and white matter. The diagnosis of Fahr's syndrome revealing hypoparathyroidism was made. The patient was supplemented with calcium and vitamin D in combination with antiepileptics. The evolution was marked by the cessation of seizures and the correction of calcium level.Fahr's syndrome is a rare entity contrasting severe and various symptoms with simple and effective treatment. Our cases report emphasize the importance of the search of abnormal phosphocalcic metabolism and cerebral calcifications associated with the presence of neuropsychiatric disorders in order to adopt the appropriate therapeutic measures.