Abstract
Background/Objectives Hashimoto’s encephalopathy is a neuroimmunological disease associated with anti-thyroid antibodies. Cognitive dysfunction and behavioural change are prominent, though clinical manifestations are wide and include seizures, movement disorders, cerebellar dysfunction and altered consciousness. The entity, including its nomenclature, is a source of some debate and consequently, a treatment consensus is lacking.
Tocilizumab, an interleukin-6-receptor inhibitor, has demonstrated benefit in the treatment of autoimmune encephalitis, however its use in Hashimoto’s encephalopathy has not previously been reported.
Methods Case report.
Results A 64-year-old female with a history of psoriatic arthritis developed rapidly progressive global cognitive dysfunction and mood disturbance. She scored 52/100 in the ‘Addenbrookes cognitive examination revised’ (ACE-R) with severe impairment of memory and executive function. The patient additionally had headache, dystonic head tremor and non-epileptic events characterised by behavioural arrest and repetitive movements. Her MRI showed white matter hyperintensities. FDG PET of the brain was normal, the CSF was normal but prolonged EEG showed diffuse slowing consistent with encephalopathy and serum thyroglobulin and thyroid peroxidase antibodies were identified, with titres of 28.2 kIU/L and 70 kIU/L respectively. Intravenous and oral steroids only had a modest effect and cognition deteriorated on weaning. Monthly intravenous Tocilizumab was started and led to a rapid and sustained improvement in symptoms over 12 months (ACE-R score of 87/100).
Conclusion Hashimoto’s encephalopathy is typically steroid-responsive, presumably due to the reduction of pro-inflammatory cytokines. In this refractory case, blocking interleukin-6 led to a rapid and more pronounced recovery than treatment with steroids.
