Background: Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) also known as Hashimotos encephalopathy (HE), is a rare immune-mediated complication independent of functional status of thyroid, which leads to either stroke-like symptoms, or presents as diffuse progressive symptoms of altered mental status, seizures, and cognitive dysfunction. Here we present a case of SREAT in a female with recurrent episodes.
Case history: A 54-year-old female was brought in by ambulance after a prolonged tonic-clonic generalised seizure, requiring intubation with a Glasgow coma scale (GCS) of 6/15. Her past medical history was significant for autoimmune hyperthyroidism, epilepsy, smoker and alcohol excess. She did have previous ITU admissions with a similar episodes and after ruling out all possible causes of encephalitis; was treated as SREAT (based on EEG, thyroid history and cerebrospinal fluid (CSF) raised protein); with a 5 day course of i.v. methylprednisolone with good response. Her medications included propylthiouracil (PTU) 50mg twice-a-day and levetiracetam 1250 mg twice-a-day.
Investigations on admission: Renal and liver function tests and full blood cout were normal. TSH 0.29, T4 23, T3 3.2; normal CSF biochemistrymicrobiology/virology (except CSF protein raised at 0.7 g/l), and normal CT head. Antibodies for other causes of encephalitis were negative. Her Anti-TPO antibodies and TSH-receptor antibodies were both positive.
Treatment: While sedated she continued to be in non-convulsive status. Due to the background of autoimmune thyroiditis/possible SREAT and the above mentioned investigations, a trial of methylprednisolone 1 g i.v. was given for 5 days. She improved dramatically achieving usual mental status and GCS within 24 h.
Discussion: SREAT or HE is a rare diagnosis but the recognition of this uncommon condition is essential for early diagnosis and treatment.