Endocrine Abstracts

Case history: A 35-year-old female presented to a district general hospital with convulsive status epilepticus. In the two weeks preceding the seizure, she complained of migrainous-type headaches, transient aphasia and ataxia. Her general practitioner organised a confusion screen, revealing hypothyroidism and commenced levothyroxine 50 μg. She had no other medical history and denied illicit drug use or alcohol-excess. Examination revealed mild pyrexia (38.2°C), clonus and brisk reflexes. Following termination of seizures, the patient was intubated.

Investigations: Admission bloods and arterial gases found no abnormality other than raised c-reactive protein (35.1 mg/l). Chest X-ray, CT head and MRI head/neck were reported normal. Lumbar puncture found normal opening pressure, clear fluid and high-normal protein on analysis with negative viral polymerase-chain-reaction studies. Further bloods on day two revealed hypothyroidism (thyroid stimulating hormone 13.2 mU/l, free-thyroxine 13.8 pmol/l), low vitamin-B12 (129.0 ng/l) and low folate (3.0 ug/l). Complement and auto-antibody screen found anti-thyroid peroxidase levels of 1130.0 IU/l.

Treatment: Prior to cerebro-spinal fluid (CSF) analysis, the patient received 24 h of intravenous aciclovir. On ITU, her condition rapidly improved and she was extubated just 40 h post-intubation. A diagnosis of Hashimoto’s Encephalopathy (HE) was suspected by neurologists and levothyroxine was increased to 100 μg. Following extubation, intravenous co-amoxiclav was commenced for aspiration pneumonia and hydroxocobalamin was administered. On day three, she was remarkably well and discharged home.

Conclusions: Brain et al. [1] first described HE in 1966 following a case of neuropsychiatric impairment in a middle-aged man with Hashimoto’s thyroiditis. Since then, there have been over 100 published case studies [2]; although pathophysiology of the condition is still poorly understood. HE is a rare diagnosis, predominantly affecting middle-aged women with a sub-acute onset over weeks [3]. A 2011 systematic review of reported cases found seizures (60%), myoclonus (65%), transient aphasia (80%) and ataxia (65%) were the most common presentations of the disease [2]. The diagnosis is one of exclusion in addition to some key diagnostic features including high titres of anti-thyroid antibodies in serum/CSF, encephalopathy and rapid response to steroids [4]. However, spontaneous recovery has been reported in over ten cases [2]. We explore the controversies surrounding a diagnosis of HE, draw parallels and review differences in our case study compared to the current literature and discuss key learning points.