頸椎症を合併したイヌ回虫幼虫移行症による横断性脊髄炎の1例

A Case of the Myelitis Due to Toxocara Canis Infection Complicated with Cervical Spondylosis

Ⅰ．は じ め に

　本邦では寄生虫感染症は稀となり，日常診療においてわれわれ脳神経外科医の念頭に上ることは少なくなっているのが現状と考えられる．しかし，最近では，イヌ回虫，ブタ回虫症などの食品媒介寄生虫症，幼虫移行症はむしろ増加傾向を示しているともいわれる⁹⁾．

　われわれは今回，頸椎症性脊髄症にイヌ回虫幼虫移行症による脊髄炎を合併したと考えられた1症例を経験した．イヌ回虫幼虫移行症による脊髄炎は稀な疾患であり，われわれが日常的に遭遇することは少ないと考えられるが，脊髄症の鑑別疾患の1つとして認識しておくことが重要と考えられたので文献的考察を加えて報告する．

　A 59-year-old male had suffered from numbness of the hands for 7 months. With a diagnosis of cervical spondylosis,he had been treated conservatively at a nearby clinic. After he fell off his bicycle,the numbness intensified and limb weakness developed. Cervical MRI revealed spinal cord compression at the C4/5 and C5/6 levels due to cervical spondylosis with prominent edema in the spinal cord spreading from the C4 to C6 level. The edema was very serious. Therefore,we suspected that the traumatic spinal injury underlying the cervical spondylosis was complicated by another disease. Cervical spinal angiography revealed no apparent vascular disorder. Contrast enhanced MRI showed a small enhanced area in the spinal cord at the C5 level. Because of the rapid progression of gait disturbance,expansive laminoplasty was performed without further examination. Although remarkable amelioration of the symptoms was seen just after the surgery,the symptoms worsened again about 1 month later. The patient's clinical history was reconsidered,revealing that he likes raw bovine liver. Serological examination,because of suspicion of parasitic infection showed elevated titers of anti-Toxocara canis antibody in the serum and cerebrospinal fluid. Administration of albendazole improved the clinical symptoms,and normalized the serological and MRI findings.

　Myelitis due to T. canis infection is a rare disease. For an early and accurate diagnosis,it is important to be fully aware of this disease and to include detailed information on food preferences and pet-keeping in the process of compiling a clinical history.