A case of Hashimoto's encephalopathy misdiagnosed as viral encephalitis.

Patient: Male, 61 FINAL DIAGNOSIS: Hashimoto's encephalopathy Symptoms: Neuropsychiatric or neurological manifestations Medication: Steroids and immunoglobulins Clinical Procedure: Immunoglobulin combined with corticosteroid therapy Specialty: Neurology.

Objective: Mistake in diagnosis.

Background: Hashimoto's encephalopathy is a rare autoimmune syndrome characterized by various neuropsychiatric or neurological manifestations and associated with Hashimoto's thyroiditis, responsive to steroids. Until now, misdiagnosis and delay of treatment of Hashimoto's encephalopathy are very common because of the diversity of the symptoms.

Case Report: This recent case of a 61-year-old man presented with unconsciousness, spasms and a previous misdiagnosis as viral encephalitis. Response to anti-viral and steroid therapy was unsatisfactory, but treatment with immunoglobulin combined with corticosteroid therapy achieved rapid and complete recovery.

Conclusions: Any patient presenting with acute or subacute unexplained encephalopathy should be considered Hashimoto's encephalopathy, even if the thyroid function is normal. Thyroid antibody testing should be performed because this may be the most important clue to diagnosis. As soon as the diagnosis is made, steroid therapy is the first choice. If the steroid therapy does not lead to immediate improvement, IVIG is an effective alternative treatment.