Clinical Worsening Despite Various Imunotherapy In Hashimoto- Antibodies-Associated-Encephalopathy

Background: In 1966, first description of a “Steroid-Responsive Encephalopathy Associated with autoimmune Thyroiditis (SREAT)” syndrome was described. Since then, lots of cases emerged with two major kinds of presentations: “vasculitic” and “diffuse progressive”. Patients respond variably to corticoids. Methotrexate, plasmatic exchange or intravenous imunoglobulins (IvIG) have only been anecdotically used. Case Report: A 63 years old man presented with mild words finding difficulties evolving for 5 years in 2000. He lost appetite and was tired despite sleeping 10 hours/day for 3 years. He presented bradypsychia and his MMSE was 28/30. Diagnosis of depression was made and treated. At this time, he fell asleep while eating or watching TV. EEGs and usual blood investigations were normal. During the next three years, he presented left extinction and extra-pyramidal gait followed by spontaneous myoclonus. Both lumbar puncture and brain MRI were normal despite atrophy. Diagnosis of cortical posterior atrophy due to possible corticobasal degeneration was then set up. Cognitive decline rapidly progressed and anti-TPO antibodies were positive at >3000 UI/ml. Treatment by oral methylprednisolone (64mg/day during 1 month) was then initiated and followed by a delirious major depressive disorder requiring hospitalization. Over the next years, cognitive decline persisted and treatments by methotrexate, prednisolone and even IvIG were all followed by worsening of myoclonus and psychosis relapses. Conclusion: This case of clinical worsening after immunotherapy highlights the necessity to cautiously study the response of SREAT to immune-therapies.