頚髄損傷者にみられるクローヌスや筋痙攣に対する循環反応

頚髄損傷者にみられるクローヌスや筋痙攣が循環動態に与える影響について検討することを目的とした.対象者はC7レベルでの男性頚髄損傷者2名(症例1:年齢41歳;身長172 cm;体重55kg;罹病年数;10年)とし,損傷レベル以下での感覚機能,運動機能ともに消失していた(ASIA gradeA).5分間の車椅子安静座位の後,対象者の麻痺域末梢部に求心性の刺激を加えクローヌスや筋痙攣を誘発した.その際,収縮期血圧(BP),1回拍出量(SV),心拍出量(CO),全末梢血管抵抗値(TPR),心拍数(HR),腓腹筋部ヘモグロビン量(TotalHb),心拍変動高周波成分(HF),腓腹筋筋電図を記録した.刺激により腓腹筋の収縮が筋電図により確認された.症例1ではBP, HR, CO, TPR,HF が増加したが,SV は安静時の80%まで減少した.症例2ではBP, SV, CO,HFは増加した.さらにHRは刺激を加えた直後に,いったん安静時の150%まで増加した後,安静時の75%まで減少した.TPRは安静時の60%まで減少した後,安静時の150%まで増加した.また,TotalHbは両症例ともに変化しなかった.したがって,クローヌスや筋痙攣の出現とともに循環動態に変化がもたらされ血圧が上昇することが示され,末梢部の求心性刺激によるクローヌスや筋痙攣は脊髄内に異常興奮を生じ,反射性の交感神経活動により心臓や血管に影響を与えたことが考えられた.

The purpose of this study was to examine the effect of clonus and muscle spasm on the cardiovascularresponses of patients with cervical cord injury (CCI). Two males with a lesion at C7 volunteered for thisstudy (Case 1: age 44 years; height 172 cm; weight 55 kg; duration of injury 20 years. Case 2: age 31 years;height 171 cm; weight 50 kg; duration of injury 10 years.). The subjects showed no sensory or motor belowthe level of the lesion (ASIA grade A). Following a rest period of 5 minutes in the wheelchair, peripheralafferent stimulation was performed in subjects. Systolic arterial blood pressure (BP), stroke volume (SV),Cardiac output (CO), Total peripheral resistance (TPR), heart rate (HR), total hemoglobin of calf(TotalHb), high frequency of heart rate variability (HF), and electromyogram (EMG) of gastrocnemiuschanges were measured. In result, following the stimulation, contraction of gastrocnemius wererecognized with EMG. In case 1, BP, HR, CO, TPR and HF increased, whereas SV decreased by about80%.0In case 2, BP, SV, CO and HF increased. Immediately after stimulation, HR increased by about 150-0x1.fcfap+0nd then decreased by about 75%.0 TPR decreased by about 60-0x1.4b3a0b6a4aap-149nd then increased by about 150%.0 TotalHbshowed no change in either subject. These results suggested that clonus and muscle spasm inducedcircular reaction and a marked BP. Peripheral afferent stimulation during Clonus and muscle spasm that isinduced by intraspinal hypersthenia decentralized part of the sympathetic nervous system and influencedheart and blood vessels.