Endocrine Abstracts

Background: Hashimoto’s encephalopathy is a rare steroid-responsive condition associated with high antithyroid antibody titres. We report a case of autoimmune thyroiditis presenting with status epileptics.

Case: A 36-year-old non-epileptic Caucasian lady presented as an emergency with uncontrolled generalised seizures requiring sedation, short-term ventilation and maintenance sodium valproate therapy. Further enquiry revealed a 3–4 week history of personality change, loss of memory and easy fatiguability, and a 1 week history of facial twitching. She had no previous history to suggest an underlying tendency to seizures and her past medical history was unremarkable. There was a family history of autoimmune thyroid disease. Physical examination was normal but higher mental functions were significantly impaired (initial Addenbrooke’s cognitive examination (ACE) score 74/100).

Investigations revealed normal full blood count, clotting, ESR, liver and renal function, calcium and glucose. Anti-nuclear antibodies were detectable at 1:100 but anti-dsDNA, ENA and ANCA were all negative. CT scan of the head was normal as was a subsequent MRI including a T1 coronal volume sequence. The EEG showed no focal abnormalities. Cerebrospinal fluid protein was marginally raised but no organisms were seen and culture was negative. Anti-voltage gated potassium channel antibodies and anti-neuronal antibodies were negative. Thyroid function tests showed normal FT4 of 15.8 pmol/l and raised TSH of 30.23 mU/l; anti-TPO antibodies were markedly elevated (>1300 kU/l; normal <60). She was treated with thyroxine replacement, pulsed methylprednisolone and maintenance high-dose oral prednisolone. Her memory improved markedly with a rise in ACE score to 86/100 at discharge.

Discussion: Although seizures are a well-recognised feature of Hashimoto’s encephalopathy, it is rarely considered in the differential diagnosis of epilepsy. Our case illustrates the importance of thyroid function assessment in patients with unexplained status epilepticus and reinforces the value of high dose corticosteroid therapy in the treatment of Hashimoto’s encephalopathy.