認知症症状を呈する疾患の臨床検査

Laboratory tests for dementia

早期に治療を行えば回復が期待できる“治療可能な認知症”を適切に診断することは臨床において極めて重要である．“治療可能な認知症”に該当する疾患群の診断に臨床検査はとりわけ有用であり，適切な検査を行えば比較的容易に診断できることも多いが，診断の遅延は重大な後遺症に直結しうるため注意が必要である．本稿では認知症症状を呈する疾患の臨床検査について述べ，代表的な疾患である甲状腺機能低下症，肝性脳症，チアミン欠乏症について概説する．

Dementia diseases occur from a variety of causes, some of which are reversible, while others not.　Reversible dementia, or treatable dementia, includes infectious, cerebrovascular, endocrine, metabolic, collagen, and toxic diseases.　These potentially treatable conditions can be often diagnosed from specific laboratory results.　However, a delay of correct diagnosis and treatment can lead to devastating disability or even to death.　In this article, we presented a review of treatable dementia, especially hypothyroidism, hepatic encephalopathy, and thiamine deficiency.　We also described the importance of laboratory studies for the early diagnosis of dementia causes.