We report a longstanding selective memory deficit in a euthyroid 45-year-old woman who was being treated with levothyroxine for Hashimoto thyroiditis. The patient had complained of memory problems and deterioration of her concentration skills for about 2 years. Her endocrinologist thought that she was depressed. The patient’s physical examination was normal. She scored a full 30 points on the Mini-Mental State Examination, but neuropsychological evaluation showed a significant deficit in her verbal memory. Routine blood tests and cerebrospinal fluid analysis showed only antithyroid peroxidase antibodies. Brain magnetic resonance imaging was normal. Electroencephalogram showed scarce intermittent bilateral multifocal theta waves. We increased the patient’s daily dose of levothyroxine and started her on dexamethasone therapy. Five months later, we repeated the entire evaluation and found both her cognitive function and her electroencephalogram to be normal. Autoimmune encephalopathy associated with Hashimoto thyroiditis is already known to present with either stroke-like episodes or diffuse progressive deterioration. Our patient shows that the encephalopathy can present as a chronic selective memory deficit that can spare executive functions and short-term memory. This presentation can be missed or mistaken for depression, but can be diagnosed with a detailed neuropsychological evaluation.
*Cognitive Neurology-Extrapyramidal Disorders Unit, 1st University Department of Neurology, Eginition Hospital, Medical School
†Department of Psychology, University of Athens, Athens, Greece
‡Endocrine Unit, Aretaieion Hospital, Medical School, University of Athens, Greece
The authors declare no conflicts of interest.
Reprints: Christos Koros, MD, PhD, Cognitive Neurology-Extrapyramidal Disorders Unit, 1st University Department of Neurology, Eginition Hospital, University of Athens Medical School, Vassilisis Sofias Avenue 72-74, Athens 11528, Greece (e-mail: firstname.lastname@example.org).
Received October 8, 2011
Accepted May 24, 2012