Endocrine Abstracts

Neurological complications of thyroid disease are well recognised; however the distinct clinical entity of encephalopathy associated with autoimmune thyroid disease has been only occasionally reported in the paediatric population. We describe a case of Hashimoto’s encephalopathy (HE) in a teenage girl.

A 13-year-old girl presented with seizures and prolonged confusion. Baseline blood tests, CSF analysis and CT Brain were essentially normal. She was discharged with the diagnosis of possibly an epileptic seizure. Over the next 3 weeks she re-presented with 2 further episodes of prolonged periods of confusion and visual hallucination. Extended investigation examining infective, metabolic and auto-immune causes of encephalopathy were negative except for much raised thyroid peroxidise antibodies (anti-TPO levels of 2767 IU/ml; Normal range 0–60 IU/l). Her thyroid function tests showed hypothyroidism: TSH – 12.51 mU/l (0.35–5.5), T₄ – 9.4 pmol/l (11–19.5) and T₃ – 4.8 pmol/l (3.5–6.5). She was commenced on thyroxine and a tapering course of prednisolone as treatment for presumed HE.

She has remained symptom free for over 8 months now.

HE is a disorder with persisting or fluctuating neurological symptoms in a patient with high anti-TPO antibody levels. Diagnosis is based on the triad of neuropsychiatric symptoms, detection of anti-TPO antibodies in blood and the elimination of other causes. Clinical response to corticosteroid therapy also supports the diagnosis. There is no correlation between antibody levels and clinical severity of illness. HE is unrelated to thyroid function status and affected individuals are usually euthyroid or mildly hypothyroid. Long-term prognosis is good, with 90% of patients in remission after 10 years. HE is likely to be under-diagnosed in children due to a low level of suspicion. Awareness of this disease is important as most patients respond to steroid therapy.