Endocrine Abstracts

Global encephalopathy is a rare complication of Hashimoto’s thyroiditis. It typically presents with seizures, ataxia and tremors and responds to steroid therapy. Limbic encephalitis (LE) is even less well described in paediatric population. It presents with medio-temporal lobe symptoms (memory impairment, temporal lobe seizures and disturbances of affect) caused by inflammation within the hippocampus, amygdala, hypothalamus, insular and cingulate cortex. LE most commonly presents as a paraneoplastic phenomenon, although non-paraneoplastic LE has been described. To date, LE in thyroiditis has not been described in children.

A previously healthy nine-year old-boy presented to hospital in status epilepticus, with subsequent encephalopathy. Encephalopathy screen confirmed hypothyroidism (TSH >100, FT₄ 8.6, FT₃ 4.7) and ruled out alternative pathology. Thyroid peroxidise antibodies were 711 IU/l and ultrasound scan confirmed a vascular goitre. A presumptive diagnosis of Hashimoto’s encephalopathy (HE) was made. He developed expressive aphasia, impaired short-term memory and psychosis. MRI scan confirmed evidence of medio-temporal encephalitis with symmetrical progressive high T2 signalling in the hippocampi consistent with LE. EEG showed high amplitude slow waves over posterior quadrant of the left hemisphere. He was subsequently managed with levothyroxine (75 μg daily) and prednisolone. He showed slow clinical improvement and is currently undergoing neuro-rehabilitation.

A recent case series on limbic encephalitis described 10 cases from 12 European centres. Although thyroid peroxidase antibodies were detected in three out of the seven patients, there was no other clinical or biochemical evidence to suggest LE secondary to Hashimoto’s disease. Hereby we describe the first paediatric case of limbic encephalitis in Hashimoto’s thyroiditis. We propose that MRI scan is the diagnostic method required to confirm this association.