筋萎縮性側索硬化症との鑑別を要したヒトTリンパ球向性ウイルス脊髄症（HAM）の1例

Differentiating Between HTLV-1 Associated Myelopathy and Amyotrophic Lateral Sclerosis: A Case Report

緩徐進行性の下肢の痙性麻痺と有痛性筋痙攣を主訴とした72歳女性を経験した。痙性麻痺は左下肢から始まり，4カ月後に右下肢に拡大した。左優位の両下肢痙性麻痺，線維束性収縮，四肢腱反射亢進，病的反射陽性から筋萎縮性側索硬化症（ALS）を考えた。しかし，脳脊髄液検査にて細胞数増多と蛋白上昇を認め，血清ラインブロット法および脳脊髄液中のHTLV-1がCLIA法で陽性であることを確認し，ヒトTリンパ球向性ウイルス脊髄症（HAM）と診断した。ステロイドにて治療を行い，症状は改善している。HAMは片側の痙性麻痺で発症し，かつ線維束性収縮を伴い得ることから，ALSとの鑑別が困難な場合があり，注意を要する。

Abstract

We present the case of a 72-year-old woman with slowly progressive spastic paraplegia and painful muscle spasms of the lower limbs. Spastic paraplegia began in the left lower extremity and extended to the right lower extremity 4 months later. We considered the diagnosis of amyotrophic lateral sclerosis (ALS) because of the left-dominant spastic paraplegia of bilateral lower limbs and due to the presence of fasciculation, hyperreflexias, and pathological reflexes. However, cerebrospinal fluid (CSF) examination revealed that cell count and protein values were increased. The patient also had an increased titer of anti-HTLV-1 antibodies in serum and CSF and was diagnosed with HTLV-1 associated myelopathy (HAM). She was treated with steroids, and her symptoms improved. Distinguishing HAM from ALS may be difficult because HAM may present with unilateral spastic paralysis and may be accompanied by fasciculation. Careful and accurate evaluation is necessitated to differentiate between these conditions for a conclusive diagnosis.

(Received 1 March, 2021; Accepted 26 April, 2021; Published 1 September, 2021)