Convulsive Seizures Revealing Hashimoto’s Encephalopathy

Abstract

Introduction: Hashimoto encephalopathy (HE) is an autoimmune disease with different neurological and psychiatric characteristics. It is associated with increased thyroperoxidase autoantibodies. The diagnosis of HE is clinical and involves 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 agitation. 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 discharge 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.