Encephalopathy associated to autoimmune thyroid disease: a more appropriate term for an underestimated condition?

Hashimoto's encephalopathy is a severe and rather infrequent clinical condi tion initially described in patients suffering from chronic lymphocytic thy roiditis. Its origin is still controversial but it can be agreed to have an autoimmune etiology. In fact, its most characteristic finding is the high titre of antithyroid antibodies, especially antimicrosomal. We describe thr ee cases of Hashimoto's encephalopathy and establish a relationship between the clinical status, the antithyroid antibody levels and its response to c orticosteroid treatment. There was an excellent response to corticosteroid treatment in all three cases. Interestingly, one case was associated with C raves' disease. Given this, and after the review of the literature, we beli eve that the term 'encephalopathy associated to autoimmune thyroid disease' could be more appropriate to define this entity. Finally, we suggest that autoimmune thyroid encephalopathy must be suspected in the face of unaccoun ted acute or subacute encephalopathy with high levels of antithyroid antibo dies. (C) 2000 Elsevier Science B.V. All rights reserved.