[Case of Graves' disease presenting only with rapid consciousness disturbance].

A 79-year-old woman was admitted to our hospital because of forgetfulness for a month followed with rapid development of consciousness disturbance. After admission, the depressed consciousness level fluctuated but continued for more than a month. Thyroid function tests showed increased free T3 and T4 level, lowered level of TSH, and increased anti-TSH receptor antibody titer. A diagnosis of Graves' disease was made but we could find none of thyrotoxic manifestations such as goiter, exophthalmos, tachycardia, high body temperature, or sweating. Administration of thiamazole rapidly improved her consciousness level. It should be kept in mind that hyperthyroidism in elderly could present solely with psychoneurologic symptoms or consiousness disturbance.