Hindawi Publishing Corporation Case Reports in Medicine Volume 2012, Article ID 782127, 2 pages doi:10.1155/2012/782127 Case Report Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis Presenting as Confusion, Dysphasia, and Myoclonus S. A. Ryan, C. Kennedy, and H. J. Harrington Department of Neurology, Mercy University Hospital, Cork, Ireland Correspondence should be addressed to S. A. Ryan, stephenryan0@gmail.com Received 29 January 2012; Accepted 17 April 2012 Academic Editor: Walter Schulz-Schaeﬀer Copyright © 2012 S. A. Ryan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Steroid response encephalopathy associated with autoimmune thyroiditis (SREAT), or Hashimoto’s encephalopathy, is a rare disorder believed to be immune-mediated. It is most often characterized by a subacute onset of confusion with altered level of consciousness, seizures, and myoclonus. We describe the case of a 48-year-old gentleman who presented with confusion and dysphasia. Speciﬁc clinical features and laboratory results led to a diagnosis of Hashimoto’s encephalopathy. This case highlights the core features of this condition and the potential for complete response to steroid therapy. 1. Introduction Steroid response encephalopathy associated with autoim- mune thyroiditis (SREAT) is a rare disorder ﬁrst described in 1966. It can present acutely with multiple recurrent focal neurological events or with a progressive, diﬀuse pattern characterized by cognitive impairment. It is under- recognized by physicians, and the purpose of this report is to add to the literature and highlight the potential for excellent clinical outcome with appropriate therapy. 2. Case Presentation A 48-year-old gentleman presented to the emergency depart- ment with a six-hour history of confusion and dysphasia. He was a smoker of ﬁve cigars a day and consumed 40 units of alcohol per week. His past medical history was notable for an episode of pancreatitis. His son had type 1 diabetes mellitus; family history was, otherwise, unremarkable. His wife described two discrete episodes of bizarre behaviour in the year prior to his current admission. She reported behaviour such as shaking salt into his tea and mixing up various household utensils. The ﬁrst of these episodes lasted three days and was associated with ataxia. The second, six months later, was associated with an expressive dysphasia. Investigations at that time included routine bloods, ANA, ANCA, CT brain, MRI brain, and EEG, all of which were normal. A lumbar puncture during the second episode yielded CSF with normal cytology but an elevated protein of 1 g. His work colleagues also reported some intermittent unusual behaviour and subtle personality changes in recent months. His clinical condition improved spontaneously on both of these occasions and a presumptive diagnosis of transient ischaemic attacks was made. When reviewed in the emergency department on this occasion, he was agitated. Vital signs were normal. He had an expressive dysphasia and appeared disorientated and confused scoring 26/30 on the minimental state score (MMSE). Cranial and peripheral nerve examinations were normal, as was fundoscopy. There was no meningism. Cardiorespiratory and abdominal examinations were nor- mal. Initial investigations revealed normal full blood count, inﬂammatory markers, electrolytes, and renal function. Liver function tests, alpha-feto protein, and ammonia levels were normal. CK was mildly elevated at 211. CT brain and MRI brain using a 1.5 Tesla machine were normal. CSF analysis revealed an elevated protein of 0.81 with normal cytology and glucose. EEG revealed intermixed theta activity. Over the following days, he developed myoclonus, a marked startle reﬂex, diﬀuse rigidity, hyperreﬂexia, and a ﬁne tremor. He also developed generalised seizures. Further laboratory tests including VDRL, TPHA, ANCA, anti-GBM, heavy metal screen, antineuronal antibodies, red cell transketolase, brucella, mycoplasma, and lyme serology