Convulsive Seizures Revealing Hashimoto’s Encephalopathy

Introduction: Hashimoto encephalopathy (HE) is an autoimmune disease with different neurological and psychiatric characteristics. It is associated with in-creased thyroperoxidase autoantibodies. The diagnosis of HE is clinical and in-volves the detection of serum thyroperoxidase (TPO) antibodies and the exclusion of other etiologies. A clinical response to corticosteroid therapy supports the diagnosis. We report a case of HE revealed by convulsive seizures and cognitive and behavioral disorders. Observation: She is a 7-year-old child followed in a neurology unit for convulsive seizures for one year. Clinical examination performed in the endocrinology unit later found tachycardia without goiter, behavioral disorders, difficulties to concentrate as well as psychomotor agita-tion. Biological work up revealed subclinical hypothyroidism, positive anti-TPO antibodies with normal thyroid ultrasound and brain MRI. The cerebrospinal fluid was clear, normotensive and absence of pleocytosis. The sleep-wake electroencephalogram was well organized for her age with a paroxysmal dis-charge in the left parieto-temporal region. Based on these clinical, biological and morphological data, the diagnosis of HE was retained. Corticosteroid therapy with prednisone at 1 mg/kg/day was initiated for 6 weeks while reducing the dose progressively. There was a good clinical and biological progress under treatment. Conclusion: Hashimoto’s encephalopathy is a rare, but probably unrecognized entity. Over the past decades, knowledge about thyroid, brain, immunity interactions has increased. This indicates the importance of a multidisciplinary approach of endocrinologists, neurologists, psychiatrists and pediatricians for early recognition and treatment.