Endocrine Abstracts

History: A 33-year-old man presented to emergency with weight loss of 3 months duration, intermittent sweating and heat intolerance. He had a brother with thyroid disease treated with levothyroxine and did not smoke. He was tremulous and short of breath, with a regular heart rate of 115b/min and blood pressure of 143/71mmHg. Initial assessment showed mildly diffuse non-tender goitre with a bruit, no cervical lymphadenopathy, mild proptosis with mild scleral congestion. TSH 0.01; FT4 88 pmol/l and FT3 30 pmol/l, normal blood glucose and PH, renal function, electrolytes and complete blood count. Inflammatory screen was normal. He was commenced on carbimazole 40mg daily, propranolol 20mg twice daily, and discharged home. Two days later, he re-presented with generalised tonic-clonic seizures during an afternoon nap. His girlfriend described the event during which he was unresponsive. This lasted for few minutes. There was no tongue biting or incontinence. He denied headaches, nor visual phenomena and had no aura, and had been taking his new medications. Post event, he was drowsy, disoriented and had no recollection of events. During his admission, he had two further seizures as described above, witnessed by staff, with full recovery over some hours. Each time, there was no demonstrable neurological deficits.

Results: Further investigations as below: CT brain normal. Echo: Non-dilated chambers, LV ejection fraction is >55% with no diastolic dysfunction. Immunoglobulins: within normal, no serum paraprotein detected. TPO abs >1300.0 iu/ml (0.0 - 60.0) TSH receptor antibodies and TG antibodies present. MRI head: normal EEG: Occasional faster activity over the frontal region. No epileptiform activity and no focal change.

Diagnosis: A diagnosis of autoimmune thyrotoxicosis was made and patient continued carbimazole 40 mg daily, titrated according to biochemical response. He completed twelve-month anti-thyroid therapy, and was successfully weaned off medications, maintaining euthyroidism off carbimazole. He has remained seizure free and did not require treatment with anti-epileptic medications.

Points for Discussion:: 1) It is well known that hyperthyroidism is associated with central nervous system dysfunction like hyperexcitation, irritability and disturbance in consciousness but clear-cut seizure disorder is rare prompting us to do a literature search which returned under 15 case reports.2) Moreso, our patient was started on propranolol to control his symptoms. Although it was only a small dose, it is unclear what role this played in precipitating the seizures as propranolol has been named as a drug that could lower seizure threshold in overdose.