ESPE Abstracts

Background: Steroid responsive encephalopathy with autoimmune thyroiditis (SREAT) is a clinically and electrographically heterogeneous steroid-responsive encephalopathy associated with thyroid autoantibodies.

Objective and hypotheses: To investigate, whether children and adolescents with Hashimoto’s Thyroiditis (HT) lacking acute clinical manifestation of SREAT show electroencephalogram (EEG) alterations, and to compare EEGs of HT patients with those of healthy subjects.

Method: EEGs were performed in 31 patients with HT recruited via our paediatric-endocrine clinics and in 28 healthy controls matched for age and gender. Antibodies against thyroperoxidase and thyroglobulin were determined in all subjects. TSH and fT4 in HT were analysed in patients only.

Results: Mean age of HT patients was 14.9 years (range 8.0–18.0 years), mean age of controls 14.3 years (range 10.0–18.0 years), without significant difference. The patients’ fT4 values were all within the age-appropriate normal range. 19 patients had normal TSH values, while 7 had values marginally above, and 5 slightly below the normal range. No thyroid antibodies could be detected in control subjects. 8 out of 31 EEGs in the HT patient and 1 out of 28 EEGs in the control group were found to be abnormal (P<0.05, Fisher’s exact test). While EEG abnormalities such as photoparoxysmal response, focal sharp waves, and bilateral synchronous spike-waves, differed not between the two groups, HT patients showed significantly more often a mild to moderate background slowing than controls (P<0.05, Fisher’s exact test).

Conclusion: Children/adolescents with HT without clinical signs of SREAT present more often with EEG abnormalities compared healthy controls. This could indicate a cerebral concurring in Hashimoto’s thyroiditis. We speculate that those alterations might lead to SREAT as the maximal manifestation. Consequently, we suggest regular EEG checks in patients with HT.