Hashimoto Encephalopathy and Neuralgic Amyotrophy – Causal Link or Chance Association?

Introduction Hashimoto encephalopathy (HE) is a syndrome consisting of encephalopathy and high serum antithyroid antibodies fi rst described in 1966 [1] . Two subtypes have been proposed: (i) a diffuse progressive type clinically dominated by psychosis or dementia and seizures and (ii) a vasculitic type with stroke-like episodes. Laboratory fi ndings are abnormal electroencephalography with diffuse slowing and/or ictal discharges and a high CSF protein concentration [2, 3] . Magnetic resonance imaging (MRI) may be normal or reveal reversible diffuse white matter hyperintensities also in the temporal lobes or brainstem on T 2 -weigthed and diffusion-weighted images as well as atrophy [4, 5] . So far, symptoms reported in HE have been confi ned to the central nervous system. Here, we report a case of HE with concurrent affection of the brachial plexus (neuralgic amyotrophy; NA) and later mild sensory neuropathy, suggesting that the disease may also involve the peripheral nervous system.