Ethambutol Neuropathyの臨床

CLINICAL STUDY OF ETHAMBUTOL NEUROPATHY

I．はじめに

　StreptolnycinをはじめIsoniazidum （INA），Cyclos—erineなど種々の抗結核剤が神経系に対して障害を起こすことはよく知られており，抗結核剤はいずれも神経親和性ないし神経中毒性の特徴をもつているといえよう。近年二次抗結核剤としてEthambutol （以下EBと略す），Rifampicinが用いられ著効を示すことが知られてきたが，EBもまた神経系に対して種々の障害をあたえることが報告されている。

　EBによる神経障害としては視神経障害の多いことが注目されているが，SMON類似のmyelo-optico-neu—ropathyの臨床像を示してくることが多い。しかしながら従来あまり充分な報告がみられないので，その臨床的特徴と発生因子について検討を加えてみたので，ここに報告する。

Clinical and electrophysiological studies wereperformed on 22 cases with neuropathy due toEthambutol (EB) administration, and possible patho-genesis of the neuropathy was discussed.

In the majority of the cases, neuropathic symptomsappeared within 3 to 6 months after the start ofthe administration of EB. The initial symptomwas most often numbness and tingling of the lowerlimbs, but was occasionally visual disturbance.Loss of sensation in the lower limbs was the mainneurologic signs with a form of sensory- or sensory-motor neuropathy. Pain and temperature sensationswere most severely affected. The level of the dis-turbance was usually below the knees, but in somecases sensory loss ascended up to the lower abdomen.Usually visual disturbance appeared one or twomonths after the onset of sensory loss.

Maximal motor conduction velocity was deter-mined on both upper and lower limbs. It signi-ficantly decreased in the lower limbs, while waswithin normal range in the upper.

In addition to visual disturbance and peripheralneuropathy, more than half of the cases disclosedexaggeration of knee jerk, and a few of them hadhyperreflexia of deep tendon reflexes of both upperand lower limbs. These findings were consideredto be indicative of myelo-optico-neuropathy as theclinical feature of EB neuropathy.