Echolalia: Presentation of Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis

Excerpt

To the Editor: A 12-y-old, previously healthy boy presented with acute onset echolalia for 10 d. There was no history of prodromal febrile illness, impaired socialization with peers, emotional apathy or mood lability, encephalopathy, seizure, or any other abnormal movements. On further questioning, the parents revealed the child had impaired sleep and easy forgettability for simple instructions recently, though the physical examination was grossly normal and the child was oriented, without any delusion, illusion, hallucination, or impaired mood. He had poor attention, executive function, and impaired recent and working memory. Mini-mental status examination score was 18 suggestive of moderate impairment. Magnetic resonance imaging (MRI) of the brain, electroencephalography (EEG), and cerebrospinal fluid (CSF) examination were normal. Work up for neuronal surface autoantibodies including anti-N-methyl-D-aspartate (anti-NMDA) receptor antibody, antineuronal antibodies, anti-nuclear antibodies (ANA), anti-nuclear cytoplasmic antibodies (ANCA), and serum anti-streptolysin O (ASO) were negative. The anti-thyroid peroxidase (anti-TPO) antibody was strongly positive 728 IU/ml, whereas the thyroid function test was normal. The child was started on intravenous methylprednisolone pulse therapy for five days followed by oral prednisolone for two weeks, with a diagnosis of steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) or Hashimoto encephalopathy. At 4 wk follow-up, he showed near-complete resolution of echolalia, memory, and sleep disturbance and had slight impairment in executive function. His repeat (at 4 wk) anti-TPO antibody levels were mildly elevated (31 IU/ml) with normal FT3 (1.24 ng/dl), FT4 (7.6 ng/dl) and thyroid stimulating hormone (TSH, 3.13 mU/L) levels. …