Wallenberg症候群におけるcentral post-stroke painの検討

Central Post-stroke Pain in Wallenberg Syndrome

　要旨　Wallenberg症候群32例において，central post-stroke pain（CPSP）の臨床的特徴を検討した。CPSPは14例（44％）に認められ，うち13例はビリビリとした灼熱痛ないし熱感であった。このうちの1例と残りの1例の計2例では慢性期に顔面の発作性激痛を認めた。Currierらの分類でtypical typeの温痛覚低下を示した症例では急性期に病巣側顔面，ventral typeでは亜急性期，慢性期に反対側の上下肢に生じることが多かった。CPSPの主な機序は，延髄外側でneospinothalamic tractが障害され，脳幹網様体を通るpaleospinothalamic tractが障害を免れるためと考えられる。Ventral typeで慢性期にCPSPが生じる機序は，急性期には脳浮腫のため脳幹網様体全体が障害されるが，慢性期には病変が限局し機能が残存したpaleospinothalamic tractが過剰反応するためと考えた。

　We analyzed clinical characteristics of central post-stroke pain（CPSP）, constant and burning pain, in 32 patients with Wallenberg syndrome due to infarction. CPSP developed in 44%（14/32） of the patients; 8 in acute stage（within 4 days after the stroke） and 8 in chronic stage（10-120 days after the stroke）. Apart from one exceptional case, CPSP was present in the hypalgesic side of face and extremities. In 9 cases of typical type（Currier's distribution of sensory disturbance）, CPSP occurred in the ipsilateral face to the lesion during acute stage. Among them, 2 cases developed severe lancinating pain in chronic stage. In 5 cases of ventral type, it occurred in the contralateral extremities during chronic stage.

　Spino- and trigemino-thalamic tract are injured but medullary reticular formation is intact in Wallenberg syndrome. It is, therefore, considered that CPSP in Wallenberg syndrome is caused by denervation sensitivity of “paleo-reticulothalamic” tract within the reticular formation.

（Received : December 5, 2003）