🔙 Quay lại trang tải sách pdf ebook Bệnh thần kinh ngoại vi Ebooks Nhóm Zalo GS. TS. HO HUTU LlfCfNG G IANG VIEN CAO CAP BENH THAN KINH NGOAI VI GS.TS. HO HOU LtfONG GIANG VIEN CAO CAP BENH THAN KINH NGOAIVI ■ N H A x u a t ban y h o c H A NOI - 2005 Chitting I DAI CITONG VE BENH THAN KINH NGOAI VI I. DAC DIEM CHUNG Than kinh ngoai vi bao gom cac day, re, dam roi, day than kinh tuy song va cac day than kinh so nao. Benh than kinh ngoai vi rat pho bien. Theo Ho Hiiu Ludng va cong stf (1991), benh than kinh ngoai vi chiem ty le tifdng doi cao (38,36%) trong cac benh than kinh noi chung, trong do dai dien cho he than kinh ngoai vi chi diidi la hoi chiing that liing - hong (chiem t6i 60,32%) va dai dien cho he than kinh chi tren la hoi chvfng co - vai - canh tay. Hoi chiing nay thifdng gap trong hii xiidng sun cot song co (cervical osteochondrosis), chiem 2,53% tong so' benh nhan n&m dieu tri tai Khoa than kinh Benh vien 103 trong 10 nam - tti 1980 den 1989). Thiidng ton cua he than kinh ngoai vi thifdng dan den nhflng roi loan nang ne cac chilc nang van dong, cam giac va thiic vat dinh diidng. Hon nuia neu la mot thiidng ton trUOng dien thi benh con co the dan den thoai hoa cac day than kinh ngoai vi gay nen thUdng ton than kinh lau dai. II. DAC DIEM GIAI PHAU THAN KINH NGOAI VI Day than kinh song co hai re, re trudc hay re van dong, re sau hay re cam giac. Re cam giac co hach gai. Hai re chap lai thanh day than kinh song. Moi day than kinh song chia ra thanh hai nhanh: nhanh sau phan bo" 3 cho cac cd cham, cd phia sau co va liing. Nhutng nhanh trUdc to hdn phan bo"cho cac cd va da phan trUdc than va chi. Hinh 1.1: do r l day TK ngoai vi 1 - Re trufdc 2 - Re sau 3 - Hach gai 4 - Nhanh sau cua day TK song 5 - Nhanh tri/dc cua day TK song 6 - Dam roi TK 7 - Day TK song 8 - Nhanh thong trang 9 - Nhanh thong xam 10 - Hach giao cam canh song Nhiing nhanh trUdc cua khoanh tuy liing hinh thanh cac day than kinh gian siidn. Nhiing nhanh trUdc cua cac khoanh tuy co, tuy that liing va tuy cung ket hop vdi nhau mot cach nhat dinh hdp thanh nhiJng bo (fasciculi) cua cac dam roi co - canh tay va that lung - cung. Tu dam 4 roi cho ra nhiing than (trunci) hay day than kinh ngoai vi. Khi cac day than kinh bi thtfdng ton, cC khong nhan diidc kich thi'ch va se bi liet. i'V I Slvn Is)VIII -4----------- --------------—► Hinh 1.3: Sieu cau true cua day than kinh ngoai vi (Theo J.D Waggener va Coll 1965) 6 Da so cac day thin kinh ngoai vi la cac day hon hop bao gom nhflng sdi van dong cua re trvfdc (axon cua te bao suing trade), nhiing sdi cam giac (duoi gai cua cac te bao hach gai) va cac sdi giao cam, doi giao cam (van mach, bai tiet, dinh difdng) tii sifng ben cua chat xam tuy song va chuoi hach giao cam canh song. Do do khi day than kinh ngoai vi bi thUdng ton thi gay ra cac roi loan van dong, cam giac, van mach va bai tiet, dinh dUdng. Axon Te bao Schwann Hinh 1.4: Qua trinh phat trien cua te bao Schwann va sdi true 7 Myelin Axon Myelin Hinh 1.5: do sieu cau true tren mot that vong Ranvier (Thiet do difng doc theo J. Poirier, 1968) Dua vao chutc nang va sU co hay khong co bao myelin ngUdi ta phan loai sdi than dinh: sdi A la sdi co bao myelin thuoc he than kinh nao - tuy. Sdi B la sdi co bao myelin thuoc he TK thtfc vat, sdi C khong co bao myelin thuoc he than kinh thUc vat. Nhutng sdi A dufdc phan chia thanh Aa, A[3, A,y... Noi chung cac sdi co dUdng kinh cang 16n thi to"c do din truyen cang cao, cac sdi co difdng kinh cang be thi toe do dan truyen cang cham. Cac sdi 16n lien quan den 8 chOfc nang van dong va cam giac ban the, cac sdi be tham gia vao chiic nang thUc vat va cam giac dau. Cac sdi co ki'ch thtfdc khac nhau thi tinh nhay cam doi BANG 1.1: CAC LOA1 SOI TK 0 DONG VAT CO VU Loai sdi Bi/dng kinh (micro - met) Toe do dan truyen (m/sec) Chute nang A. alpha (Aa ) 12 - 22 70 - 120 Van dong cd xtfdng cam giac ban the A. beta B. (AP) A.Gamma (A y) A delta (A 6) 8 - 12 40 - 70 Xuc giac, ap luC 4 - 8 15 - 40 Xuc giac, ap lUc van dong thoi cd 1 - 4 5 - 15 Cam giac nhiet, ap lut, dau. B 1 - 3 3 - 12 Cac sdi tru6c hach TK thut vat C 0 ,5 - 1 0,5 - 2 Cac sdi sau hach TK thi/c vat dau, ap life, nhiet. vdi su: thieu Oxy (hypoxie) va cac thuoc vo cam (anesthesie) cung khac nhau. NhiJng sdi truyen cam dau la nhuing sdi co dadng kinh nho, co myelin (sdi A delta) hoac khong myelin (sdi C). Thuoc vo cam tai cho co the lam mat stf dan truyen cua cac sdi C. 9 hi. su’THOAi hoA VA tAi sinh CAC sdi thA n kinh Binh thUdng sdi true dUdc bao quanh bdi cac te bao Schwann xep canh nhau doc theo chieu dai cua no. Cac te bao Schwann chi cach nhau mot khe nho goi la that vong Ranvier. NhvJng sdi khong co myelin, moi te bao Schwann chi cuon quanh mot sdi true va tu phan doan. Mot trong nhiing chiic nang cua bao myelin la lam tang nhanh toe do dan truyen luong than kinh. Nhii vay sdi co myelin truyen nhanh hdn nhiing sdi khong co myelin. 1. Thoai hoa Waller (do Waller mo ta lan dau tien (1856): khi c&t dtit day than kinh, cac sdi true se bi thoai hoa, dac biet tram trong la d phan ngoai vi, lam cho neuron mat han chiic nang sinh ly, sau mot thdi gian dai m6i hoi phuc dUdc: O than neuron 48 gid sau khi cat, cac the Nissl (nhilng hat mau xam, chiia nhieu phan til ARN (acidribonucleic) co tac dung tong hdp protein) bien mat het, lUdi td TK (nhiing sdi co dtfdng kinh khoang 90A°, dan thanh mot mang lu6i trong than neuron) bi tan vd, than neuron nd ra va nhan bi day lech sang mot ben; neu thUdng ton qua nang thi nhan cung bi tieu tan va neuron hoan toan bi pha huy. Thong thUdng tvf ngay thii hai mUdi, d cho cat nhiing tua bao tufdng se raoc ra va b it diu thdi ky hoi phuc. - Phan ngoai vi sdi true bi ckt (hinh 1.6): 24 gid sau khi bi cat, bao myelin bi vd thanh tting mang, sdi true bi tan bien chi con lai mot ong bao Schwann rong. cac tg' bao Schwann nd to ra lap ca ong. 10 ai hoa va tai sinh sdi than kinh theo J. Poirier Chevreau co sifa doi - Su tai sinh cua sdi than kinh xay ra rat cham. Nhiing te bao Schwann con lai d cho sdi than kinh bi thoai hoa bat dau phat trien theo hu6ng trung tarn. TCf than neuron cac tua bao tUdng bat dau moc ra, moi ngay dai them 0,5mm, mot so" tua chui vao dUdc ong bao Schwann thi dai ra vdi toe do nhanh hdn: 3 den 4mm trong mot ngay, ldp myelin cung dUdc ta; tao. Sau khoang 3 thang neuron co the hoan toan hoi phuc nhUng doi khi keo dai hang nam. 2. Viem day than kinh quanh true tifng doan (nevrite sementaire periaxile) La hau qua cua thUdng ton nguyen phat cua te bao Schwann (hinh 1.6) bieu hien bdi sii mat bao myelin d mot hay nhieu doan. IV. PHAN LCAI BENH THAN KINH NGOAI VI 1. Phan loai theo vi tri thiidng ton Phan loai theo vi tri thifdng ton neuron than kinh ngoai vi (re, dam roi, day than kinh). Day chi la nhiing quy u6c tUdng doi vi viem re thifdng lan sang day va ngiidc lai thUdng ton day thiidng lan sang re than kinh. 2. Phan loai theo nguyen nhan thvfOng ton Benh than kinh ngoai vi co the la nguyen phat hoac thii phat. - Nguyen phat: ThUdng ton bit nguon tif than kinh ngoai vi (vi khuan trUc tiep lam thUdng ton day than kinh hoac chan thUdng trUc tiep gay nen diit, giap day than kinh). - Thii phat: sau mot thUdng ton cua cot song, nhiem doc chi, asen, thieu vitamin Bl (benh Beriberi). 12 3. Phan loai theo mufc do thiiofng ton a. V i sinh ly hoc Theo Seddan chia ra ba rmlc do: Day than kinh bi dilt hoan toan (neurotmesis): bao va day than kinh deu bi cat va mat tinh dan truyen cua sdi true, neu khong mo de no! lai thi khong the phuc hoi. Dau hieu lam sang dilt hoan toan day than kinh la tat ca cac sdi cd do day than kinh chi phoi deu bi liet roi teo di, mat phan xa gan xUdng, mat cam giac d vung da tUdng ilng. Sau do khu vUc mat cam giac se thu hep lai nhd co cac sdi than kinh lan can. Da d vung mat cam giac bi kho do kha nang bai tiet mo hoi cung bi mat. Mat cac song dap ilng khi do dan truyen than kinh. Loai thUdng ton nay rat kho hoi phuc va thUdng tao thanh cac u than kinh (neurinoma). - Day than kinh bi dilt khong hoan toan (axonotmesis): Thoai hoa bao than kinh va mat dan truyen cua sdi true, co dau hieu liet va mat cam giac khong hoan toan, giam bien do dap ting cua cac song than kinh. Tuy co kha nang hoi phuc sau mot thdi gian nhUng doi v6i nhiing day than kinh co nhieu sdi giao cam thi co kha nang dan den chilng dau chay (causagie). Sii hoi phuc phu thuoc vao sii tai phan bo cac sdi than kinh. Qua trinh nay dien ra cham keo dai hang thang hoac hang nam vefi toe do 1 - 3mm/24gid. + Day than kinh khong bi thUdng ton ma chi roi loan chilc nang tam thdi (neuropraxia): khong co thay doi cau true sdi true mac du toe do dan truyen co the bi giam mot thdi gian neu co pho'i hdp mat myelin. Khi thUdng ton 13 myelin dUdc hoi phuc hoan toan thi toe do dan truyen se trd lai binh thUdng. b. Ve giai phau benh hoc - ThUdng ton gidi han d bao (viem quanh day than kinh): - ThUdng ton d mo ke (viem ke day than kinh). - ThUdng ton d nhu mo day thin kinh: sdi true nam d trong bao mat myelin nen co benh canh giong nhu cua thoai hoa Waller sau khi day than kinh bi cit dtit. c. Ve to chiic hoc vd dien sinh ly *Chia lam 3 loai - Thoai hoa Waller do ngat doan cua sdi true , sdi true (thUdng ton vi mach) Thoai hoa sdi true hifcing tam con goi la hien tUdng chet ngifdc (dying back) do roi loan chuyen hoa cua neuron Mat myelin tvfng doan 4. Phan loai thtfcfng ton than kinh cua Pierre Koskas (1991) va Aminoff (1992) Bang 1.2: Phan loai thifdng ton than kinh ngoai vi cua P. Koskas va Aminoff. Benh than kinh mat myelin Benh than kinh sdi true Toe do dan truyen giam tren 30% Thdi gian tiem tang keo dai tren 40% Thdi gian tiem tang cua song F keo dai tren 40% Hiem co dien tif phat khi cd nghi Bien do dien the qiam nhe 14 Giam (10% - 30%) Keo dai khong ro rang Binh thi/dng Co khi cd nghi Giam nhieu Thoai hoa Waller va sdi true thifdng phoi hdp v6i giam bien do dien the hoat dong va co cac bieu hien mat chi phoi than kinh tren dien cd. Ngifdc lai mat myelin dac trUng bdi giam toe do dan truyen. V. NGUYEN NHAN THLfONG TON THAN KINH NGOAI VI Co nhieu nguyen nhan gay thUOng ton TKNV, hay gap la thoai hoa cot song, thoat vi dla dem, nhiem khuan, nhiem doc, chan thUdng, do lanh, do dung thuoc... Moi benh TKNV co the do mot hoac nhieu nguyen nhan chi phoi hdp 1. Viem re than kinh a. Benh can - Viem mang nao do giang mai, lao, viem mang nao mu. - Chan thUdng - Thoat vi dla dem chen ep vao re than kinh Thii phat sau benh Pott, u ngoai tuy, di can ung thu hay viem nao. - Zona b. Giai phau benh hoc Cac re than kinh khi rdi khoi tuy tao thanh bo sdi than kinh difdc bao boc bdi mang nhen noi tiep vdi mang mem. Cac nhom te bao bieu mo phu, cac re than kinh d cac doan noi tao dieu kien tot cho cac qua trinh viem. Tuy theo vi tri giai phau ma phan biet ra: Viem re than kinh co - canh tay Viem rl than kinh lifng Viem re than kinh that lifng - cung 15 2. Viem dam roi than kinh Thudng d mot ben, bat dau bang giai doan dau day than kinh tu phat, tang len khi cii dong va khi de ep vao dam roi, sau do co the la giai doan liet kem theo giam phan xa, teo cd, roi loan cam giac va roi loan dinh dUdng (phu ne, tang tiet mo hoi, roi loan van mach). Tuy theo khu tru ma phan biet ra cac viem dam roi co, canh tay, that lifng - cung va then. Dam roi co it khi bi thUdng ton don doc. Dam roi canh tay (C5 - D2) hay bi thUdng ton nhat. Nguyen nhan co the la phinh dong mach du6i don, u, thUdng ton hach bach huyet, xUdng sifdn co va cac the khac cua hoi chilng sifdn don. Nguyen nhan pho bien nhat la chan thifdng (doi khi kem theo trat khdp vai). - Dam roi that lifng (Ll - L4) n&m d trong va d tren mat cd that lufng (m. psoas), co the bi thUdng ton trong viem tlnh mach huyet khoi d vung chau, viem cd that liing, cac u d chau hong nho va gay xvfdng chau. - Dam roi cung (L5 - S2) n&m tren cd thap (m.piriformis) phla trUdc phu bdi can chau va cac lcip cua mang bung. Nguyen nhan thUdng ton cung giong nhu viem dam roi that lifng. Trong thifdng ton do chan thifdng dam roi that lung - cung, ngoai trieu chilng cua dam roi co the co ca trieu chvfng cac re cua duoi ngifa (do keo cang qua mile). 3. Dau day than kinh va viem day than kinh a. Dau day than kinh Dac diem cua dau day than kinh la dau doc day than kinh, nhieu khi khong co nguyen nhan thuc the ro rang, 16 khong kem roi loan chtic nang thUc sU d cac cd quan hoac cac cd tUdng ting. Cac cdn dau thudng d mot ben, phat sinh do bi kfch thi'ch mot vung nhat dinh. Ngoai cdn khong co roi loan khach quan. Trong thuc te thudng hay gap dau day than kinh hong to, day than kinh gitia, day than kinh gian sUdn. b. Viem day than kinh - Benh can: Chan thUdng trUc tiep, dung dap, cang keo, tiem thuoc. Nhiem doc: thudng lam thudng ton nhieu day than kinh. Do lanh: chu yeu trong liet mat. Do nhiem khuan. TrUdng hdp viem mot day than kinh thudng do cd che de ep hoac thieu mau cuc bo hoac ca hai yeu to' do gay ra. Giai phau benh hoc: ThUdng ton co the gidi han (viem quanh day than kinh) hay d mo ke (viem ke day than kinh) d cac sdi than kinh (viem nhu mo day than kinh). Trong hai trUdng hdp dau, thay co dich ri viem v6i nhting bach cau, tang sinh cac nhan Schwann va dtit quang bao myelin. Trong viem nhu mo day thin kinh, sdi true ton tai d trong bao mat myelin nen co benh canh giong nhu thoai hoa Waller sau khi cit mot day than kinh ngoai vi. VI. CG CHE THl/CfNG TON THAN KINH NGOAI VI ThufOng ton rieng le mot phan day than kinh ngoai vi hau nhu luon luon do nguyen nhan cd hoc, chan thtfdng T 2 - BTKNV 17 tnlc tiep, cang keo hay de ep. Cac nguyen nhan nay co the la dot ngot hay tti tti, co the mot lan hay nhieu lan do vi chan thifdng (micro - traumatismes): hau qua cua cac nguyen nhan nay gay nen: De ep mot day than kinh trong thoi gian ngan: mat cac chtic nang trong vai phut. Cac chtic nang difdc hoi phuc ngay va toan bo neu khong con de ep ntia. De ep trong thdi gian dai hoac vi chan thifdng lap di lap lai: thifdng ton mat myelin tting doan va ngting dan truyen than kinh, thieu sot cac chtic nang than kinh. Neu co thifdng ton sdi true thi sU hoi phuc than kinh se bi keo dai. TrUdng hdp thifdng ton do cang keo hay thieu mau co the gay nen roi loan chtic nang nghiem trong va ben vting do gay cac sdi true va thoai hoa Waller. Sil hoi phuc theo quy luat tai sinh d dau gin (1,5mm mot ngay). Neu khong bi dtit day thin kinh thi sii hoi phuc chtic nang se rat tot. Neu bi dtit day thin kinh ma khong khau noi hai diu bi cat thi svf tai sinh se khong co ket qua. Do roi loan chuyen hoa va benh ly vi mach (xem benh thin kinh ngoai vi do dai thao difdng) VII. TRIEU CHLTNG LAM SANG BENH THAN KINH NGOAI VI 1. Roi loan van dong Liet mem hay liet cd chi phoi bcii day than kinh bi thifdng ton. 18 2. Roi loan phan xa Giam hoac mat phan xa gan xifdng 3. Roi loan cam giac Dau doc theo diidng di cua day than kinh bi thudng ton va dau theo vung chi phoi cua nhanh day thin kinh do. Dau khi an vao day than kinh. Giam cam giac hoac tang cam giac (thiidng la tang cam giac dau: hyperalagesia) hay di cam (cam giac te buon, kien bo, kim cham, dau chay, rat) 4. Roi loan dinh diiOng Teo cd sdm va co phan ting thoai hoa dien 5. Roi loan van mach, thay doi nhiet do da 6. Khong roi loan cd vong (trvf hoi chting duoi ngtfa). 7. Khong co dau hieu thifcfng ton bo thap VIII. LlTONG GIA sire c d BANG T A Y 1. Cac bac hoat dong cua cd Galton (1883) nhan thay stic cd d nam gidi tang nhanh tti 2 den 19 tuoi cung vdi sil tang can nang, sau do tang cham hdn va tang dan tdi 30 tuoi roi giam dan tdi 60 tuoi. Stic cd cua nti gidi tang vdi nhip do deu dan hdn tti 9 - 1 9 tuoi roi tang cham hdn tdi 30 tuoi, sau do giam dan vdi nhip do nhii d nam gidi. Schochrin (1935) nhan thay stic cd d nti gidi kem hdn nam gidi tti 28 - 30%. Lovett (1922) da de xuat phildng phap danh gia trong lildng toi 19 da ma mot nhom cd the nang len diidc (trong dieu kien hoat dong kh6p binh thiidng). Lovett va Martin (1915) da de ra phiidng phap thif nghiem sOfc cd co sxi dung mot loai can lo so. Dariels va Werthingham (1956) can cti tren ba yeu to" de phan chia cac bac cd: - Siic can cua mot cd hay mot nhom cd - Kha nang di dong cua mot phan cd the khi mot cd hay mot nhom cd co - Tinh trang co hay khong co co cd trong mot nhom cd. Ngoai cac bac can ban, trong thiic te con co the them cac dau cong hoac trii kem theo. Cu the la: siic cd chong lai it hdn cac bac can ban thi them dau trii, neu siic chong lai 16n hdn thi them dau cong vao bac can ban. Neu cU dong 16n hdn mot nUa tam hoat dong nhiing khong het tam thi dung bac cd cao hdn va them dau trif. NgUdi ta thUdng ghi phoi hdp tam hoat dong vao bac cd. Vi du, tam hoat dong thu dong gap khuyu bi gi6i han d 90 do va benh nhan co the cU dong diidc het tam hoat dong nay khi co liic can, tren sO do se dUdc ghi la 90° F (Fair = kha). Theo Weller (1973) kham siic cd nen lam cach khoang thdi gian deu nhau va ket qua diidc so sanh v6i lin kham trii6c. Kham siic cd bang tay chi co gia tri khi mot ngUdi lam nhieu lan, mot so ngUdi co xu hiidng dat he thong bac so cao hdn hay thap hdn ngiidi khac, thong thiidng thi ngiidi nao cung luon luon danh gia siic cd theo mot cap do rieng cua ho. Co nhieu he thong khac nhau de danh gia siic cd. Tat ca deu co gia tri nhat dinh. Ta co the dung mot he thong nao cung dUdc mien la ta luon luon dung mot he thong va ngUdi khac hieu ro y nghia cua no. 20 Ngo The Vinh (1981) cho biet: trong nhiing nam gan day co nhieu dung cu cd hoc va dien tii v6i mile do phiic tap khac nhau diioc ap dung de do siic cd vdi hy vong cung cap diidc nhiing dtf kien co gia tri ve chiic nang, coi do la mot dong gop quan trong cua cac cong trinh nghien ciiu. Tuy nhien, mot chiec may du tinh xao den dau cung khong the phat hien thay cho ngUdi kham tat ca nhiing bien thien te nhi trong th i nghiem cd. May khong the cam nhan ve sii co" gSng cua benh nhan cung nhu khong the phat hien sii khac biet giiia yeu cO do nguyen nhan chiic nang hoac thiic the. Them vao do, sii phiic tap ve ky thuat, viec dat co" dinh may tren tOfng phan than the doi hoi mat nhieu thi gid ma cung khong cung cap diidc nhiing dii kien hdn mot cach tUOng xiing. Do do phiidng phap thu nghiem siic cd bing tay luon luon giuf nguyen gia tri hiiu ich trong thiic tien, khong chi quan trong trong lam sang ma ca trong nghien ciiu niia. J. Godebout va J.Ster (1976) cho rang: ban danh gia siic cd giup cho viec xac dinh vi tri thiidng ton (d tuy, d dam roi than kinh hay d day than kinh), chi dan nhiing can thiep ngoai khoa, danh gia hoat dong cua khdp va cho phep tien liiOng kha nang hoi phuc chiic nang van dong. Viec liidng gia siic cd la tUdng doi kho khan nen moi tac gia co mot he thong bac rieng bang so" hoac b&ng chii: N (normal = binh thiidng), G (good = tot), F (fair = kha), P (poor = kem), T (trace = chut it), 0 (so" khong) (bang 3). Neu dung he thong so 16n thi phiic tap, khong thvic te" lam sang. Nhiing neu dung he thong so" be thi khong day du. Ho Hiiu Liidng (1976), tren cd sd nghien ciiu phuc hoi chiic nang van dong cho cac benh nhan liet hai chi dudi do vet thiidng hoac chan thiidng cot song - tuy song da 21 de xuat he thong tti 0 den 10 de ltfdng gia stic sd va theo doi qua trinh phuc hoi chtic nang van dong, dong thdi can cti vao stic cd ma chia ra 5 do liet (bang 1.3). Bang 1.3: So sanh cac bac hoat dong cua cd Lovett Loman Kendal! Dennen Hoi H. H. 1917 1922 (1936) 1940 dong NCYHQ T (D Li/dng 1976 Binh 9 100% N 5 10 thifdng 8 1 9 tot 7 80% G+ G G Kha 6 50% F+ 4 8 7 (Liet do 1) 6 F F 3 5 (Liet do 2) Yeu 5 30% P+ 2 4 4 20% P P 3 (Liet do 3) Rat yeu 3 2 1 5% T 1 2 1 (Liet do 4) Liet 0 0 0 0 0 hoan toan (Liet do 5) 22 Bang 1.4: LUdng gia sUc cd theo he thong so tUO den 10 va 5 do Net (theo Ho HOfu Ludng 1976) Sifc cd 5 do liet 1 0 - 9 Binh thiidng - 8 - 7 Liet do 1 (liet nhe) - 6 - 5 Liet do 2 (Liet vUa) - 4 - 3 Liet do 3 (liet nang) - 2 - 1 Liet do 4 (Liet rat nang) - 0 Liet do 5 (Liet chi hoan toan) Bieu hien lam sang Bien do van dong khuc chi binh thudng, chong lai trong life va sUc can tot Bien do van dong binh thudng chong lai trong lUc va sUc can yeu. Bien do van dong binh thudng Chong lai trong lUc va sUc can rat yeu. Bien do van dong bi han che (du6i 3/4 bien do binh thudng). NhUng khi khong co trong lUc (dd cho khuc chi van dong dUdc tu do) thi bien do v ln binh thudng Nhin thay co cd nhUng khong van dong dUdc khuc chi hoac ch! van dong dUdc dudi 1/4 bien do binh thudng Hoan toan khong co cd 23 2. LtfOng gia stic cd theo he thong so tti 0 den 10 va 5 do liet cua Ho Htiu LtfOng (1976) a. Y nghla thi/c tien Trong phuc hoi chtic nang van dong, dung phifdng phap lifdng gia stic cO, nghla la tinh den stic co con ma khong quan tam den stic cO da mat (do liet) (“it is not what you have lost, but what you have left, that count” - Dr. L. Guttmann). Nhu vay tien cho viec danh gia ket qua phuc hoi chtic nang van dong. NhUng trong lam sang than kinh lai thudng quan tam den stic cO da mat (do liet) de giup cho viec xac dinh mtic do nang cua benh. Ltfdng gia stic cO theo he thong so" tti 0 den 10 tUdng ting v6i 5 do liet cua Ho Htiu Ltfdng (1976) rat thuan tien trong lam sang than kinh cung nhtf trong danh gia phuc hoi chtic nang van dong. b. Nghien citu liidng gid siic cd theo he thong so tit 0 den 10 vd 5 do liet titdng ling. - Ho Htiu Ltfdng da ltfdng gia stic ca theo he thong so tti 0 den 10 va 5 do het ttfdng ting tren 127 benh nhan liet hai chi dtfdi do vet thUOng va chan thifdng cot song - tuy song dtfOc dieu tri tai Khoa than kinh, Khoa phiu thuat than kinh Vien quan y 103, Khoa chan thifdng vien quan y 109, Khu dieu difdng Thuan Thanh (Bac Ninh), Khu dieu difdng Duy Tien, Lam Can (Ha Nam) tti 1976 - 1985). Doi tifdng nghien ctiu difdc chia thanh ba nhom de co phtfdng phap luyen tap phuc hoi, thich hdp: nhom I (64 benh nhan mdi bi thifdng), nhom II (31 benh nhan bi thifdng da mot nam), nhom III (nhom chting gom 32 benh nhan khong difdc dieu tri phuc hoi chtic nang). 24 Tat ca benh nhan deu diidc liidng gia stic cd bang tay theo he thong so' tif 0 den 10 va 5 do liet triidc va sau dieu tri phuc hoi chiic nang van dong. Liidng gia siic cd dtfdc tien hanh theo mot trinh tii nhat dinh va lap phieu danh gia siic cd, dong thdi so sanh ket qua giiia cac lin kham. Phan tich ket qua phuc hoi siic cO sau moi dot tap van dong theo cac nhom benh nhan de danh gia cac phiidng phap phuc hoi van dong. Tac gia nhan thay kha nang van dong (di chuyen) cua benh nhan phu thuoc vao siic cd con lai hoac do liet (bang 1.5). Bang 1.5: Kha nSng van dong 0 benh nhan liet hai chi diidi (theo Ho HuTu Ltfdng) Stfc cd Bo liet 1 0 - 9 B. thifdng 8 - 7 Liet do 1 6 - 5 Liet do 2 4 - 3 Liet do 3 2 - 1 Liet do 4 0 Liet do 5 Kha n3ng van dong Di bo binh thiidng T ii di dtfdc 50m Di diidc nhiing can nep ngln d hai chan Di diidc nhtfng can dat, vin hoac dung hai nang vdi nep ngan d hai chan , Difng di/dc nhurig can vjn va nep ngan d hai chan T iid i chuyen blng xe lan Neu sifc cd bung con 6 - 5 (liet do 2), co the di chuyen kieu lang ngUdi vdi hai nang va nep dai d hai chan. Neu site cd dai chau con 4 - 3 (liet do 3) co the di chuyen kieu bon thi vdi hai nang va nep dai d hai chan. 25 Danh gia kha nang phuc hoi btfdc di d 37 trUdng hop liet hai chi dtfdi dtfdc tap luyen muon, Ho Hiiu Ltfdng (1980) nhan thay: + Trtfdng hdp stfc cd hai chi dtfdi b&ng 0, benh nhan co the di chuyen kieu lang ngtfdi vdi hai nang va hai nep dai d chan khi stfc cd bung con 5 - 6/10 (liet do 2). + Di kieu bon thi vdi hai nang va hai nep dai d chan khi stfc cd dai chau con 3 - 4/10 (liet do 3). + Di vdi hai nang tay, khong c&n nep chan khi stfc cd ttf dau dtii con 5 - 6/10 (liet do 2). + Trtfdng hdp liet cting nhe hai chi dtfdi stfc cd chi con 3 - 4/10 (liet do 3), benh nhan van co the di dtfdc bang hai nang tay (khong can nep chan). + Di khong can nang vdi hai nep ngan d chan khi stfc cd dui va cang chan con 3 — 4/10 (liet do 3). - Tren cd sd nghien ctfu phuc hoi van dong sdm cho 14 thtfdng binh liet hai chi dtfdi do chan thtfdng va vet thtfdng cot song, Ho Htiu Ltfdng (1979) da dtfa ra tieu chuan phan loai mtic do hoi phuc van dong gom 8 do (bang 1.6). Bang 1.6: Do hoi phuc van dong (theo Ho Htfu Ltfdng, 1979) Hoi phuc Tinh trang van dong Mure do hoi phuc Do 1 Liet hoan toan Chtfa thay hoi phuc Do 2 Van dong mot vai cd nhtfng chtfa van dong dtfdc khuc chi Do 3 Van dong khuc chi nhtfng chtfa dtfng dtfdc Hoi phuc rat it Hoi phuc it Do 4 Di hai nang nach Hoi phuc kha Do 5 Di hai nang tay Hoi phuc rat kha Do 6 Di mot nang Hoi phuc tot 06 7 Di khong nang dtfdc 10 met Hoi phuc rat tot Do 8 Di binh thtfdng Hoi phuc hoan toan 26 IX. DIEU TRI BENH THAN KINH NGOAI VI 1. Dieu tri theo nguyen nhan 2. Dieu tri trieu chiing Dieu tri cac trieu cluing hien co cua moi benh nhan. Dau than kinh la trieu chiing hay gap va thiidng la nguyen nhan khien benh nhan phai di kham benh. 3. Dieu tri chiing dau than kinh ngoai vi: Phan loai cam giac dau: dau cam thu (nociceptive pain), dau than kinh (neuropathic pain), dau can nguyen tam ly (psychogenic pain). - Dau than kinh la chiing dau do nhiing thiidng ton cua ban than cac cau true than kinh cam giac (trung tfdng, ngoai vi). Dac diem chinh cua dau than kinh la khu tru tai vung phan bo" cua cac day than kinh hoac lan theo dai phan bo" cam giac cua re than kinh, dau ca d vung giam hay mat cam giac, tang ve dem va dap ting rat kem vdi cac thuoc giam dau truyen thong. Cac loai dau than kinh thudng gap: Dau than kinh do dai thao dtfdng Dau thin kinh sau herpes (dau sau khi bi zona) Dau day V, dau day thin kinh trung gian Wrisberg, dau day thiet hiu, dau day thin kinh hong to, dau day thin kinh dui, dau day thin kinh then trong, dau day thin kinh dui bi. Dau chi ma Dau sau dot quy nao 27 Dau do thtfdng ton tuy song... Dieu tri dau than kinh: Cac thuoc chong tram cam ba vong (amitriptylin). Cac thuoc chong dong kinh (Carbamazepin, Phenytoin, Gabapentin(Neurotin, Aclonium). Cac thuoc chong loan nhip (Mexiletine). Giam dau cuc bo va phong be giao cam. Thuoc giam dau ngoai vi (Aspirin, Paracetamol) Cac phtfdng phap khong dung thuoc. 28 ChUOng I I CAC PHlfONG PHAP THAM DO DIEN SINH LY TRONG BENH THAN KINH ■ NGOAI VI I. LICH SU” CAC PHLfdNG PHAP Nam 1791, Luigi Galvani (Bologne) da phat hien ra dong dien sinh vat, Dubois Raymond xac nhan rang dong dien do do cd phat ra. Nam 1851, Dubois - Raymond da de xuat phtfdng phap ghi dien cd va da ghi dtfdc ban dien cd dau tien. Nam 1852, Herman von Helmholtz trong khi nghien ctfu dan truyen day than kinh givia, lan dau tien da do dtfdc chinh xac toe dp dan truyen than kinh. Sau do nhd cac trang thiet bi ky thuat cua Lippman (1872) va cua DArsonval (1910), Piper (1911) da xay dtfng nen nganh khoa hoc "Dien sinh ly than kinh". Nam 1925, C.S. Sherrington de xuat danh ttf "ddn vi van dong" (cau true chtfc nang cua cd). Nam 1929, Adrian va Bronk che tao ra dien ctfc kim ltfdng ctfc dong true (aiguille coaxiale), dien ctfc nay cho phep ghi dien the hoat dong cua nhom sdi cd. Sau do la cac cong trinh cua Denny Brown ve hien ttfdng giat sdi cd (1938), ve co cd (1941) cung cac nghien ctfu cua 29 Clemmesen va Kugelberg (B ic Au), Bawens (Anh), Bremer, Desmedt (Bi), Lerique (Phap) da giup Buchthal xay dilng diidc nganh "Dien cd lam sang" vao nam 1949). Nam 1950 Dowson va Scoot da sil dung cac dong dien co tan so thap kich thich he than kinh van dong ngoai vi, cac cd va he than kinh cam giac d vi tri nong diidi da de xem xet phan ilng dien trong chan doan benh thin kinh - cd. Nam 1948, Hordes, Larabe da nghien cilu dan truyen than kinh van dong. Nam 1962 Gillatt va Thomas dung phiidng phap do din truyen thin kinh de nghien cilu cac benh ly cua day thin kinh ngoai vi va thay rang khi day than kinh bi thiidng ton thi toe do dan truyen cua chung se giam. Nam 1980 Bosch va CS nghien cilu thiidng ton dam roi thin kinh canh tay ve hinh thai va dien sinh ly khi re thin kinh cam giac bi chen ep. Sau do la thdi ky phat trien manh me cua chan doan dien. Phu'dng phap ghi dien thin kinh (neurography) dong vai tro quan trong trong chan doan cac benh TKNV. Vdi nhiing tien bo cua cong nghe vi tinh, da co cac he thong khuyech dai cilc nhay va cac he thong dien cilc thuan tien cho phep do dude toe do dan truyen van dong, cam giac cua day TKNV, cac tham kham phan xa nhil phan xa H, song F va cac phan xa thile vat. Phildng phap ghi dien the kich thich (evoked potential:EP) la mot trong nhiing phutdng phap chan doan hien dai, gom co dien the kich thich van dong (motor evoked potential), dien the kich thich cam giac (gom co dien the kich thich thi giac - visual evoked potential: VEP, dien the kich thich 30 thinh giac - auditory evoked potential:AEP va dien the kich thich cam giac than the somatosensory evoked potential: SSEP). II. DIEN SINH LY TRONG CHAN DOAN BENH THAN KINH NGOAI VI 1. Dien the mang neuron, dan truyen xung dong trong sOi true a. Dien the nghi Don vi cau true - chile nang cua c0 the don bao cung nhii da bao la te bao. Moi te bao la don vi song, co kha nang trao doi chat vdi dich ngoai bao, san xuat cac san pham cua minh va phan chia sinh te bao con. Khi neuron 6 trang thai nghi, dien the 6 mat trong mang te bao am hdn mat ngoai. Sii chenh lech dien the nay la do sii chenh lech nong do ion am va ion dutdng gitia trong va ngoai mang te bao. Sii chenh lech nong do ion nay la do: - Trong te bao, nong do protein (mang dien tich am) rat cao va khong the khuyech tan qua mang te bao de ra ngoai diidc nen nong do ion am trong mang cao hOn, ngoai mang te bao. - Sii khuyech tan cua ion Na+ va K+: binh thtfdng hai loai ion nay tham qua mang te bao vdi so' liidng rat it. Do nong do ion K+ trong mang cao hdn ngoai mang te bao nen kha nang khuyech tan ion K+ tti trong ra ngoai mang 16n hdn nhieu (100 lan) so vdi ion Na+ di tti ngoai vao trong nen nong do ion am trong mang te bao von da cao lai cang cao hdn so vdi ngoai mang 31 - Bom Na+ - K+: day la ly do chi'nh de tao ra stf chenh ech nong do ion gitfa trong va ngoai mang te bao. Bdm nay loat dong lien tuc (trti khi te bao chet). Cd m6i lan bdm loat dong co 3 ion Na+ di ra ngoai va chi co 2 ion K+ dtfpc )dm tii ngoai vao trong. Noi cach khac, sau moi lan bdm, 6 igoai mang tang them 1 ion dtfOng nen stf chenh lech nong lo ion am gitfa trong va ngoai mang cang tang len. NhU vay, khi neuron khong hoat dong, dien the mat ,rong am hdn mat ngoai mang neuron (hien ttfdng phan ;tfc). Dien the d mang sdi true la -90mV va d mang than leuron la -65mV. 3. Dien the hoat dong Dien the hoat dong cua mang b it dau bang stf bien doi dot ngot tuf dien the" am, luc nghi sang dien the difdng roi lai rat nhanh trO ve dien the am: - Giai doan nghi (giai doan phan cue): + Vai tro cua kenh natri: la loai kenh co canh cong dien the, cong phia ngoai la cong hoat hoa, cong phi'a trong la :ong khu hoat. Khi dien the mang la -90mV, cong hoat hoa dong (Na+ khong vao dtfdc), cong khtf hoat md + Vai tro cua kenh kali: cung la kenh co canh cong dien the nhtfng chi co mot cong hoat hoa nam phia trong mang te bao. O trang thai nghi cong kenh dong, K* khong ra ngoai dtfdc. Giai doan khtf ctfc: Hoat hoa kenh natri: dien the mang tang din tii - 90mV len -50mV gay bien doi cong hoat hoa lam no md ra, Na+ ua qua kenh vao trong te bao. Tinh tham cua mang vdi Na+ luc nay tang gap 500 den 5000 lan. Trang thai nay chi keo dai vai phan van giay. 32 - Giai doan tai cilc: Ngay sau khi md vai phan van giay kenh natri bat dau dong, kenh kali md lam ion K+ khuyech tan nhanh ra ngoai, tai tao lai trang thai phan ctfc luc nghi ve tri so -90mV. c. Dan truyen xung dong tren sdi true. Stf lan truyen dien the hoat dong tao nen mot mach dien tai cho gitfa vung dang khtf ctfc va phan mang 6 vung tiep giap. Lan song lan truyen nhtf vay goi la xung dong than kinh. Khi dien the hoat dong dtfpc tao ra 6 mot diem tren mang neuron, qua trinh khtf ctfc se lan toa toan bo mang theo quy luat "tat ca hoac khong". Dien the hoat dong xuat hien tai mot diem cua spi true se lan toa theo hai phia. Dong dien trong te bao chay ttf vung hoat dong (noi ti'ch dien dtfOng) den vung khong hoat dong ben canh (noi ti'ch dien am). Phia ngoai te bao xuat hien mot dong dien chay ngtfpc chieu ttf vung khong hoat dong den vung hoat dong. Hien ttfpng nay lam nhtfng vung khong hoat dong 0 hai phia cua vung hoat dong bi khtf ctfc tao nen dong dien chay theo hai htfdng. Tuy nhien ve mat sinh ly, xung dong thtfc te chi dan truyen theo chieu thuan. Doi vdi cac spi than kinh khong co myelin, cac xung dong d in truyen theo tting diem mot tren suot chieu dai spi true nen toe do din truyen khong nhanh. Cac spi thin kinh co myelin, cac xung dong din truyen theo kieu "nhay coc" qua cac eo Ranvier (do myelin la mot loai chat cach dien, mat khac mang tai eo Ranvier co tmh tham rat cao vdi cac ion (gap 500 lan cac spi khong co myelin) nen toe do dan truyen cua cac spi T 3 - BTKNV 33 than kinh co bao myelin cao hon rat nhieu so vdi cac sdi khong co bao myelin. b Hin 2.1: Dan truyen nhay cua cac sdi than kinh co myelin, a: dong dien cuc bo, b: kich thich dien gay khCr ctfc d cac eo Ranvier ke can va dong dien chay theo hai htfdng. III. CHAN DOAN DIEN CO DIEN 1. Nguyen tac Dung dong dien galvanic (dien mot chieu) (luc dong va luc md dien) va dong faradic (dien ting). 2. Nofi kich thich Doi vdi thin kinh: d ndi day than kinh gan da nhat (vi du ranh tren rong roc doi vdi day than kinh tru). Doi vdi cO: diem van dong. Neu kich thich ngat quang bln g dong dien galvanic (dong dien mot chieu) se cd xung chti nhat (hay con goi la xung vuong). Dong dien faradic (dien ting, cd xung dinh nhon hai pha: mot pha am, mot pha dtfdng ldn hdn. Binh thtfdng khi kich thich than kinh bang dong dien galvanic 34 va dong faradic se gay co cd do day than kinh do phan bo. Neu kich thich triic tiep vao cO cung gay diidc co cd. 3. Ctfcfng do cd sof (rheobase hay ngifdng kich thich) Cifdng do cd sd la Clidng do nho nhat de gay diiOc co cd. Cac day than kinh co ngifOng kich thich khac nhau diidc tinh blng mA (milliampere) mAa ► (b) "L/VAAJVM(c) Hinh 2.2: Cac loai xung thudng dung trong chan doan dien a - Xung chii nhat. b - Xung faradic. c - Xung gia faradic d - Xung ludi cay. e - Xung hinh thang 35 BANG 2.1.: NGUCfNG KICH THICH CUA DAY THAN KINH Day than kinh Ngi/dng kich thich (mA) -DTK mat 1 - 2,5 -DTK tru 0,2 - 0,9 -DTK giQa 0,3 - 1,5 - DTK quay 0,9 - 2,7 - DTK cd bi 0,04 - 0,28 - DTK dui 0,44 - 1,7 - DTK hong to 0,4 - 2,5 - DTK chay 0,4 - 2,5 - DTK mac 0,2 - 2 - DTK hong be 0, 2 - 2 Chi so" ngifdng binh thifdng la: Ngifdng faradic ---------------------------------- > NgUdng galvanic Khi co thifdng ton thoai hoa than kinh chi so phan ly ngUdng ldn hdn 2. 4. Thcfi tri (chronaxie): La thdi gian toi thieu lam cho co cd vdi mot cifdng do gap hai cifdng do cd sd. — Thdi tri day than kinh: theo Bui Thieu Stf va Lai The Vinh binh thifdng thdi tri trung binh cua cac day than kinh la: Day quay: 0,094 miligiay 36 Day tru: 0,110 miligiay Day giiia: 0,124 miligiay Day chay: 0,141 miligiay Day mac: 0,125 miligiay - Thdi tri cac cd: binh thiidng thdi tri cac cd trong cd the tu: 0,08 den 0,72 miligiay. + Cac cd d co, than va goc chi (vai, canh tay, hong, dui): Cd mat trtfdc: 0,08 - 0,16 miligiay Cd mat sau la: 0,16 - 0,32 miligiay + Cac cd d dau, mat va d ngon chi (c&ng tay, ban tay, cang chan, ban chan): Cd mat trtfdc la: 0,16 - 0,32 miligiay. Cd mat sau la: 0,44 - 0,72 miligiay Khi co hien tufpng thoai hoa than kinh hoan toan thi thdi tri co the tang gap 100 lan so vdi binh thudng. Trong qua trinh hoi phuc than kinh, thdi tri se giam dan, nhd vay ta theo ddi dtfdc sii hoi phuc than kinh. IV. MOT SO PHAN IfNG DIEN BiNH THUGNG VA BENH LY 1. Phan ling Erb Binh thiidng khi kich thich bang dong galvanic cd co chdp nhoang va co dac diem la cd co (C) khi dong (D) dien d am ctfc (A) manh hdn khi dong ctfc dUdng (D) (CDA) > (CDD). Hien ttfdng dao Ion cong thtfc CDD > CDA la phan ling Erb dtfOng tfnh. Phan ilng nay xuat hien vai tuan sau thiiOng ton than kinh. 37 Phan ting Erb dtfdng tmh thtfdng di kem theo phan ting co cO cham (phan ting Remark dtfdng tmh) phan anh tinh trang thtfdng ton tram trong cua day than kinh va te bao than kinh 2. Phan ting chieu doc Binh thtfdng kich thich c0 vdi dong galvanic tai diem van dong thi nhay hon d hai dau cO. Nhtfng sau khoang hai thang thtfOng ton day than kinh thi dap ting dan dan ngtfpc lai, den khi dap tfng d dau cd lai nhay hdn d diem van dong thi tao nen trang thai phan tfng chieu doc. 3. Phan ting thoai hoa dien a. Thdi gian xuat hien phan ting thoai hod dien Co phan tfng thoai hoa dien sau khi thtfOng ton day than kinh (DTK) hoac te bao sting trtfdc tuy 1 2 - 1 5 ngay (bang 2.2). BANG 2.2: PHAN tTNG THOAI HOA (PUTH) DIEN Dongfaradic - DTK Dong ganvanic -DTK Dong faradic - cd Dong galvanic - cd Binh thudng PUTH 1 phan PUTH hoan toan Mat hoan toan tinh chiu kich thich dien 38 Co cd Co cd Co cd Co cd chdp nhoang CDA > COD Co cd yeu Co cd yeu Co cd yeu Co cd Id dd COD >COA Khong Khong Khong Co cd Id dd COD > CDA Khong Khong Khong Khong b. Tien trien cua phan ting thoai hod dien - Thdi ky dau (vai ngay sau thiidng ton te bao than kinh ngoai vi): ngtfdng kich thich day than kinh va cd v&n binh thudng nhUng thdi tri da thay doi, kich thich day than kinh tren cho bi thUOng thay mat hoac giam dan truyen. Trong mot so trUdng hpp kich thich day than kinh b&ng dong dien galvanic va faradic deu co phan tfng dien nhay hOn binh thudng (sd do Guilleminot - hinh 2.3). - Thdi ky toan phat (vai ngay, vai thang, co khi hang nam) Phan tfng dien galvanic va faradic doi vdi day than kinh giam dan tdi mat han. Kich thich cua cd doi vdi dong dien faradic cung giam dan. Rieng doi vdi dong dien galvanic thi dtfdc chia ra ba giai doan: Tuan le dau: phan tfng giam nhe. Tuan 2,3 den 2 thang: phan tfng lai nhay hOn (ngtfdng kich thich giam xuong). Sau hai thang: phan tfng giam dan dong thdi xuat hien phan tfng Remark, phan tfng Erb dtfOng tinh CDD > CDA, chi so” ngtfdng faradic/galvanic ldn hdn 2. Thdi tri tang len cao dan roi gitf d mtfc cao, tiep sau dd xuat hien phan tfng chieu doc. Neu tien trien xau dan: tinh chat co cd ngay cang cham dan, phan tfng Erb ngay cang dtfOng tinh manh, phan tfng chieu doc cang ro, sau do dap tfng cua cd doi vdi dong dien faradic mat va tiep theo thi dap tfng cua cd do! vdi dong dien galvanic cung mat h^n. 39 Hinh 2.3: Sd do tien trien cua cac kich thich day than kinh va cd trong phan Cfng thoai hoa dien (theo Guilleminot) - Phan ling thoai hoa dien hoan toan Phan tfng thoai hoa dien hoan toan cung chiia han da tien liipng xau. Trong qua trinh hoi phuc spi than kinh, phan ling thoai hoa dien hoan toan co the chuyen sang phan ilng thoai hoa mot phan, roi sang ti'nh chiu kich thi'ch binh thudng. Nhiing neu trong liet kieu ngoai vi, cd bi mat than kinh hoan toan tren 1 2 - 1 4 thang (doi khi hdn niia) thi luc do do sii thoai hoa tuln tien, cac spi cd bi huy hoai hoan toan, diipc thay doi bang to chiic md va to chiic lien ket, xuat hien xP chai cd kem theo mat phan ling co doi vdi dong dien galvanic, nghia la mat hoan toan tinh chiu kich thich dien (mat kha nang hiing phan), tinh trang nay chilng to cac bien doi xay ra trong cd khong cdn kha nang hoi phuc 40 V. DO TOC DO D AN TRUYEN THAN KINH Do toe do dan truyen than kinh de phat hien thtfOng ton TKNV va vi tri cua thtfOng ton. 1. Nguyen ly chung Co the la moi trtfdng dan dien ki'ch thich vao mot diem cua day than kinh se tao ra dtfpc mot xung dong lan doc theo spi true den tan cung than kinh va dien the hoat dong nay co the gian tiep ghi dtfpc tren da thong qua cac dien ctfc be mat. Ghi thdi gian dan truyen xung dong ta se danh gia dtfpc tinh trang dan truyen cua day than kinh. Vdi phtfOng phap ghi dien the hoat dong neu tren, ngtfdi thay thuoc co the tham kham dtfpc tat ca cac day than kinh nam d nhtfng noi co the kich thich dien dtfpc (vi du TK chay, TK. mac, TK. hien ngoai, TK. tru, TK. gitfa). Ben canh ky thuat do toe do dan truyen dung de tham kham phan than cua cac day than kinh, con co mot so phtfOng phap nghien ctfu phan goc cua chung (phan xa H, song F, phan xa nhay mat). 2. PhtfOng phap do toe do dan truyen than kinh a. Phiictng phap do toe do dan truyen van dong - Kich thich: kich thich vao cac diem doc theo dtfdng di cua day than kinh b&ng xung vuong co do dai 0,5 giay, ctfdng do tang den mtfc thu dtfpc bien do dap tfng ctfc dai. - Ghi: dien ctfc be mat dat tai khoi co co day than kinh dinh tham dd chi phoi. 41 - Tmh toe do din truyen than kinh. Lj: thdi gian tiem tang de xuat hien dap ting R l khi kich thich vi tri A cua day than kinh (ms) L2: thdi gian tiem tang de xuat hien dap ting R2 khi kich thich vi tri B cua day than kinh (ms) D: khoang cach gitia hai diem A va B (mm) V: toe do dan truyen tti B den A (m/s). Theo cong thtic: D V = L 2 - L 1 Ta tinh dUdc toe do dan truyen than kinh hoac qua he computer ta biet dupe ket qua. Vi du do toe do dan truyen cua day than kinh gitia: diem kich thich d nep khuyu co thdi gian dan truyen xung tti nep khuyu den cho dam kim vao cO doi chieu ngon cai la 8,6miligiay; diem kich thich d cd tay co thdi gian dan truyen xung tti co tay den cho dam kim vao cd doi chieu ngon cai la 4msec thi thdi gian dan truyen tti nep khuyu den co tay la 243,8mm thi toe do dan truyen la 243,8; 4,6 = 53 met moi giay. Theo Bouche (1983), toe do dan truyen than kinh binh thudng cua day than kinh gitia tti 48 - 50 met/giay cua day than kinh tru la 42 - 45met/giay. 42 So do 2.1. Do toe do dan truyen than kinh van dong - Nhan dinh: Giam toe do dan truyen va keo dai thdi gian tiem tang phan anh thiidng ton myelin Giam bien do cac dap ting phan anh thiidng ton sdi true b. Phtfcfng phap do toe do dan truyen cam giac Chi can kich thich tai mot diem la do dUdc van toe dan truyen cua day than kinh cam giac. Co hai cach do: - Cach do thuan chieu vdi xung cam giac (orthodromic): dat dien ciic kich thich d ngon chi va dien ciic ghi d goc chi. - Cach do ngUdc chieu vdi xung cam giac (antidromic): ta phai doi dien ciic ghi thanh dien ciic kich thich va ngiidc lai. 43 Sau do ta do khoang cach tii ndi kich thich den noi dat dien cUc. Theo cong thilc : D V = t ta tinh dupe van toe dan truyen hoac qua he thong computer cua may ta se dUdc ket qua. VI. GHI SONG F Ghi song F de chan doan cac thudng ton 0 phan goc day than kinh van dong. Song F la song muon, sau song van dong M (motor) va ghi dupe 0 tat ca cac day than kinh van dong. 44 Khi ki'ch thi'ch dien tai mot diem tren day than kinh van dong se tao ra mot dien the hoat dong. Xung dong trUc tiep M den thang cd. Xung dong ngUdc chieu lan den than te bao sting trudc tuy song. Tai day, sau khi lUu lai 1ms de ki'ch thi'ch hoat hoa te bao sting trUdc tuy song phat xung dien. Xung nay di xuoi theo chi'nh sdi day than kinh do ve bap cO, gay co co nhe va tao ra song F (hinh 2.2). Nhu vay, ghi thdi gian tiem tang cua song F giup danh gia dUdc tinh trang dan truyen doan goc cua day than kinh Dac diem cua song F la thdi gian tiem tang khong on dinh d cac lan ki'ch thi'ch khac nhau (cung mot ctfdng do). Do do thdi gian tiem tang trung binh dUdc ti'nh qua 10 lan kich thi'ch va chi so F = (LF - LM - l)/2 (LF la thdi gian tiem tang cua song M, 1 la thdi gian hoat hoa te bao sting trUdc tuy song). - Chi so" song F d ngUdi binh thudng: Thtfdng ghi song F day than kinh gitia, day tru, day mac, day chay sau (xem bang 2.3) Tuoi ddi cang cao thdi gian tiem tang song F cang dai, tuoi ddi cang cao, tan so xuat hien song F cang giam. - Mot so" bat thtfdng cua song F trong benh than kinh ngoai vi: thdi gian tiem tang keo dai, tan so xuat hien song F giam, hieu so" thdi gian tiem tang song F - song M dai. Hoi chting Guillain - Barre: thdi gian tiem tang song F keo dai (d giai doan dau). Chan thUdng re than kinh: thdi gian tiem tang song F keo dai ro. Benh r§ thin kinh (radiculopathy): neu thtfdng ton chu yeu la cac sdi cam giac thi song F khong phai ltic nao cting co gia tri. 45 VII. PHAN XA H 1. Cung phan xa H. Phan xa H (phan xa Hoffmann) la cung phan xa ddn synap (monosynaptic refflex): spi htfdng tam thuoc nhom spi la (co dUOng kmh ldn) xuat phat ttf thoi co cua cd dep, trung tam phai xa la khoanh tuy S i, sdi ly tam thuoc nhom sdi alpha co than te bao nam d sting trtfdc tuy chi phoi cho cd nay. So do 2.3: Cung phan xa H. 46 Hoffmann va sau do nhieu tac gia khac da dung dong dien mot chieu kich thich vao day than kinh chay tao nen cung phan xa va phat hien mot so" thtfdng ton cua he than kinh ngoai vi. 2. Ghi phan xa H. Phan xa H la dap tfng do ki'ch thi'ch than kinh chay sau d ho"khoeo va ghi tai cd dep: - Ki'ch thi'ch: xung vuong 0,5S ki'ch thi'ch day thin kinh chay sau. Ctfdng do ki'ch thi'ch tang dan ttf 0 den khi thu dtfdc dap tfng ctfc dai (H.max.). - Ghi: dien ctfc be mat dat tai cd dep. Dien ctfc hoat dong dat tai diem gitfa dtfdng noi dinh ho" khoeo va diem gitfa bd sau mat ca trong. Dien ctfc trung tinh dat gitfa dien ctfc kich thich va dien ctfc ghi. Hinh 2.4.: Dat dien ci/c ghi phan xa H. 47 De phan xa H co diidc dap ting to'i tfu: benh nhan hoan toan thoai mai va co the lam nghiem phap Jendrassik de han che tac dung tic che cua vo nao xuong khoanh tuy S,. 3. Cac thong so - Thdi gian tiem tang cua dap ting M (LM): phan anh dan truyen ngon chi cua cac sdi van dong. - Thdi gian tiem tang cua phan xa H (LH): la thdi gian tti khi ki'ch thi'ch den khi thu dUdc dap ting. No phan anh dan truyen trong cung phan xa H (bao gom sdi cam giac sau, trung tam phan xa, sdi van dong) la thong so giup danh gia dan truyen phan goc cua day thin kinh. Neu LM d gidi han binh thudng thi keo dai LH la thudng ton dan truyen (myelin) cac sdi cam giac sau - Bien do cua dap ting M (AM): phan anh sdi true phan ngon cua cac sdi van dong Bien do dap ting cua phan xa H (AH): phan anh tinh trang sdi true cac neuron tao nen cung phan xa H. Neu AM d gidi han binh thudng thi bat thudng AH noi len thUdng ton sdi true cac sdi cam giac sau. 4. Phan xa H binh thiidng (Xem bang 2.3) 5. Phan xa H trong thiidng ton than kinh ngoai vi 0 Keo dai thdi gian tiem tang cua phan xa H Bien do giam (thudng ton than kinh trung Udng thi phan xa H co tang bien do qua mtic lam chi so’ HAI >100% (do thoat tic che trung Udng cua phan xa H). 48 - Co the dung phan xa H de phan biet thudng ton re L5 va S 1 (thUdng ton L5 thi phan xa H khong thay doi) •K O benh nhan dai thao diidng, khi phan xa H co keo dai thdi gian tiem tang, bien do giam la bieu hien sdm cua bien chiing than kinh ngoai vi. v O cac benh than kinh ngoai vi do riidu, tang ure huySt, thay doi phan xa H la chi so" cho thay thudng ton than kinh cam giac d giai doan sdm. BANG 2.3: MOT SO CHI SO DIEN SINH LY THAN KINH NGOAI VI BiNH THLTONG (THEO LE QUANG Cl/ONG CO SUA DOI). T K W Bien do (mV) TGTT (m s) TOOT (m/s) Chi so F (ms) Phan xa (n = 200) TK chay 11,95 ± 5,74 4,75 ±0,71 / 46,42± ,26 12,15±1.49 LH (ms): 27,61 ± 1,58 AH(mV): 4,14 ±2,31 LM (mS): 4,52 ±0,66 AM (mV): 13,21 ± 5, 86 6,38 ± 3,40 4,31 ±,0,70 51,87 ±6,53 13,42 ±1,52 Ghi chu - TGTT: thdi TK gian tiem tang. mac TK hien ngoai TK giGra 17,35 ±7,83 «MV) 12,11 ± 3,99 45,31 ±7,54 3,87 ±0,43 61,17 ±20,91 - TODT: toe (5o dan truyen. - LH: thdi gian tiem tang cua phan xa H. - AH: Bien do dap TK try 11,99 ± 3,68 Px. nhay miit 3,11 ±0,51 60,52 ± 7,55 R1 (ms) 10,02 ±0,89 R2 (ms)30,56 ±3,61 ting cua phan xa H. - LM: Thdi gian tiem tang cua dap uhgM. - AM: Bien do cua dap ling M. T 4 - BTKNV 49 VIII. DIEN THE KICH THICH CAM GlAC THAN THE 1. Dai cifdng PhUdng phap ghi dien than kinh (neurography) bao gom do toe do dan truyen van dong, cam giac cua day than kinh, cac phan xa dien (nhif phan xa H, song F), cac phan xa thuc vat va phifdng phap ghi dien the ki'ch thi'ch (evoked potentials = EP) gom dien the ki'ch thi'ch thinh giac (AEP) dien the ki'ch thi'ch thi giac (VEP), dien the ki'ch thich cam giac than the (somatosensory evoked potential = SEP). Phifdng phap ghi dien than kinh da giup chan doan sdm nhieu benh than kinh ngoai vi d giai doan tien lam sang va danh gia ket qua dieu tri mot cach chat che. De chan doan nhiing thifdng ton doan goc (proximal) cua cac day than kinh, cac tac gia thifdng dung phifdng phap ghi song F va phan xa H. Nhifng cac phUdng phap nay khong the iing dung dUdc cho tat ca cac day than kinh va ty le dap ling cua chung sau moi lan ki'ch thi'ch lai thay khac nhau. Phifdng phap ghi SEP cho phep ghi difdc cac song dap iing d nhieu diem tren dUdng dan truyen hudng tam, no phan anh mile do thudng ton cua day, re than kinh cl tifng doan tvf diem ki'ch thi'ch den diem ghi. Dowson d Cambridge la ngUdi dau tien ghi difdc dien the kich thi'ch cam giac than the tren benh nhan dong kinh co giat cd. Nam 1967 Halliday da che tao ra may ghi difdc SEP. Hien nay may dien cd hien tai da co the ghi difdc SEP (nhieu benh vien tai Viet Nam da co may dien cd) co the ghi dUdc SEP). 50 Khi .Ju'ch thi'ch dien vao cac day than kinh cam giac hay cam giac - van dong se co nhieu lan song dien dap ting tren man hinh cua may ghi SEP, cac lan song do diidc goi la dien the (potentials). Theo quy ildc quoc te, song nao vUdt tren dUdng dang dien la song am va dUdng neu d diidi dUdng dang dien. Dien the diidng dUdc ky hieu la P (positive) va am ky hieu la N (negative). Mot dien the ky hieu la N9 diidc hieu la dien the am, cd thdi gian tiem trung binh (d ngUdi binh thudng) xap xi 9ms, P40 la dien the diidng cd thdi gian tiem xap xi 40ms. Thdi gian tiem (latency) la thdi gian tut khi ki'ch thi'ch cho tdi dinh cua mot dien the. Bien do (amplitude) la chieu cao cua dien the tinh blng |aV. Dien the kich thich cam giac than the cd thdi gian tiem < 25ms khi kich thich d tay va <50ms khi kich thi'ch d chan la dien the cd thdi gian tiem ngan (short lantency) va diidc viet tat la SSEP.SSEP tiidng doi on dinh d ngUdi binh thudng va cd gia tri trong chan doan benh thin kinh ngoai vi va trung lidng (vi du benh xd cilng rai rac, tai bien mach mau nao), ghi triidc va trong phau thuat than kinh dac biet la phlu thuat cot song va tuy song. Phiidng phap ghi SEP cdn Uu viet hdn han phiidng phap ghi song F va phan xa H vi nd cdn khao sat diidc chiic nang din truyen doan trong tuy va trong nao. SEP cd liu the trong chin doan dan truyen thin kinh ngay tii giai doan tien lam sang. NhUng ban chat va nguyen nhan gay nen nhiing roi loan dd thi SEP khong the chi ra diidc. Ngoai vai tro chan doan, SEP cdn la phiidng phap cd the dUdc sii dung de theo doi, danh gia ket qua dieu tri hoac tien ltfdng. Hien nay ky thuat chup cat ldp vi tinh va chup cong hiidng tu! da giup chan doan chinh xac hinh anh benh ly 51 thtfc the. Nhtfng viec chan doan ch ic nang sinh ly dan truyen than kinh ckn phai lam cac ky thuat ch&n doan dien sinh ly. 2. Giai phau dtfdng dan truyen cam giac a. Ccf the ngiidi co nhieu loai cam giac - Cam giac nong: cam giac xuc giac (sd), dau, nhiet (nong, lanh). Cam giac sau: cam giac 0 cO, gan, xtfdng, khdp (gom cam giac sau cd y thtfc va cam giac sau khong cd y thtfc). Cam giac giac quan: thinh giac, khtiu giac, thi giac, vi giac, thang bing. b. He thong truyen vd phan tich cam giac - Thu the cam giac (receptor): la ndi tiep nhan cac xung dong than kinh dau tien. Dd la nhtfng d&u tan cung cua cac duoi gai cua neuron cam giac thtf nhat. Nd nam d da, cd, xtfdng khdp, quanh cac mach mau, mang nao. 0 moi vi tri nd deu cd dac ti'nh dac hieu rieng, cd nghia la moi loai thu the chi tiep nhan mot loai kich thich nhat dinh nhtf xuc giac, dau, nhiet - Dtfdng dan truyen cam giac: moi dtfdng dan truyen cam giac gom cd 3 neuron (hinh 2.5) + DUdng cam giac nong: • Neuron 1: Than te bao nam d hach gai Duoi gai (dendrid hay sdi ngoai vi: prolongement cellulipete) nhan cac kich thich ttf cac thu the dac hieu d ngoai vi va tham gia vao cau tao cac day than kinh. 52 Sdi true (axon hay sdi trung Udng: prolongement cellulifuge) khdp noi vdi neuron 2. • Neuron 2: Than te bao nam d sting sau cua tuy. Duoi gai: khdp noi vdi neuron 1 Sdi true: di len doc theo tuy song va tan cting d doi thi. Dtfdng di trong tuy cua cac neuron nay khac nhau tuy theo tting loai cam giac: Cam giac sd: sdi true di cheo qua mep xam sau tdi cot ben cua ben doi dien lam thanh bo gai - lifdi - thi (faisceau spinoreticulo - thalamique). Cam giac dau va nhiet: sdi true di cheo qua mep xam trtfdc tdi cot ben cua ben doi dien lam thanh bo gai - thi (faisceau spinothalamique). Cac sdi bat cheo khong phai d cung mot mtic khoanh tuy ma cac sdi bat cheo d cao hdn 2 - 3 khoanh tuy. Bo gai thi theo cot ben qua hanh, cau, cuong nao va tan cung d nhan ben doi thi. • Neuron 3: di tti doi thi len vo nao cting ben va tan cting d phan trUdc cua hoi dinh len. + Diidng cam giac sau Diidng cam giac sau cd y thtic, gom 3 neuron (hinh 2.5): Neuron 1: Than te bao n&m d hach gai Duoi gai tham gia vao cau tao day than kinh cam giac, nhan cac ki'ch thi'ch d cd, gan, khdp. Sdi true khong di vao sting sau tuy song ma vao ngay cot sau cung ben hdp thanh bo Goll va bo Burdach, hai bo nay di len tdi nhan Goll va nhan Burdach n&m d tram hanh. 53 Neuron 2: Than te bao nam d nhan Goll va Burdach. Duoi gai khdp noi vdi neuron 1 Sdi true bat cheo dtfdng gitfa d hanh nao (decussation piniforme) de tdi doi thi. Neuron 3 (doi thi - vo nao): Than te bao nkm d nhan bung ben cua doi thi, sdi true di tdi trung tam phan tich cam giac d vo nao nam d hoi dinh len va mot so vung khac dac biet la thuy dinh. Tren dtfdng di cua dtfdng cam giac sau cd y thtfc, bo Goll va bo Burdach nhap vao bo gai thi d doan hanh nao tren de tao thanh giai Reil gitfa. • Dtfdng dan truyen cam giac sau khong y thtfc: la dtfdng dan truyen cam giac ve do cang cua cd, gan cd, day chlng khdp trong viec gitf ttf the va trong cac phan xa gitf vtfng ttf the. Dtfdng nay ttf hach gai qua tieu nao roi mdi tdi doi thi. Theo mot so" tac gia dtfdng nay ttf hach gai chi di tdi tieu nao (dtfdng gai - tieu nao) gom cd hai neuron. Neuron 1: Than te bao n&m trong hach gai Duoi gai (sdi ngoai vi) tiep nhan cac cam giac d thoi cd, cac gan cd. - Sdi true (sdi trung tfdng) tan cung d dau sing sau tao thanh hai nhan: bong Clarke va nhan Bechterew. Neuron 2: 54 ■. J gitfa l T i Hanh nao z ' ' I T ~ K Hinh 2.5: Dtfdng cam giac (nong va sau) co y thtfc: 1. Bo gai - li/di - thi (quamep xam sau - cam giac sd) Bo gai - thi (qua mep xam trudc - cam giac sau dau va nong lanh) 3. Diidng cam ac sau co y thCfc. Hinh 2.6: Dtfdng cam giac sau khong y thtfc 1. Doi thi 2. Nhan do 3. Nhan cau nao 4. Nhan rang 5. Nhung nao 6. Nhan tien dinh 7. Nhan tram dtfdi 8. Nhan Goll, Burdach 56 Cac te bao bong Clarke di len d ntfa tuy cung ben tao thanh bo gai tieu nao thang (hay bo Flechsig) qua cuong tieu nao dtfdi vao tieu nao. Cac te bao tti nhan Bechterew bat cheo qua dtfdng gitia d mep xam trtfdc de qua ntia tuy doi dien sau do di len tao thanh bo gai - tieu nao cheo hay bo Gower, qua cuong tieu nao tren va tan cting d thuy giun tieu nao (hinh 2.6). 3. Sinh ly difcfng dan truyen cam giac a. Dieting dan truyen - Dtfdng dan truyen cam giac sau co y thtic: cac sdi true (axon) cua neuron cam giac thti nhat la nhting sdi th&n kinh nhom Ia va II, chting co dtfdng kmh 4 - 2 0 |im, co bao myelin, toe do dan truyen nhanh (30 - 110 m/s). Dtfdng dan truyen cam giac sau nay co y nghla rat ldn trong stf hinh thanh cac dien the kich thich cam giac than the. - Dtfdng dan truyen cam giac sau khong y thtic: di qua re sau vao sting sau tuy song noi tiep vdi neuron 2. Sdi true cua neuron 2 di ra cot ben cung ben tao thanh bo Flechsig (bo tieu nao thang) hoac bat cheo qua dtfdng gitia sang ria cot trang ben doi dien tao thanh bo Gowers (bo tieu nao bat cheo), hai bo nay di len tren va tan cung d thuy giun tieu nao. - Dtfdng dan truyen cam giac dau va nhiet do: cac sdi true cua neuron 1 cung di qua re sau vao sting sau tuy song, tti day neuron 2 bat dau va di cheo qua mep xam trtfdc sang cot ben doi dien tao thanh bo gai - thi, bo nay di tiep len doi thi, tti doi thi neuron 3 bat dau va di tiep len trung khu vo nao cam giac. 57 Cac sdi true cua diidng dan truyen nay thuoc cac sdi nhom III va IV co diidng kinh nho hdn 4|am, khong co bao myelin. b. Sinh ly dan truyen xung dong than kinh. Sii din truyen cam giac tii thu the len trung khu phan ti'ch cam giac d vo nao thiic chat la sii dan truyen cac xung dong than kinh. Cd che cua sii dan truyen nay la mot qua trinh lan truyen hoat dong khu ciic cua sdi te bao than kinh. Khi tai mot diem cua te bao hoac cua sdi than kinh bi ki'ch thi'ch se xay ra sii khii ciic mang te bao. Sii khii ciic nay dUdc tap cong theo ca thdi gian va khong gian den khi tao ra dUdc mot dien the khu ciic du ldn (tiic la tao ra mot dien the hoat dong) tai diem do thi no se dUdc truyen di doc te bao hoac sdi day than kinh tao nen mot xung dong than kinh (doi vdi te bao va sdi than kinh thi sii chenh lech giiia dien the trong va ngoai te bao dat khoang - 20pV (binh thiidng la -70 den -90 |iV) se gay khu ciic te bao (dien the ngiidng) va tao nen mot dien the hoat dong). Sii dan truyen xung dong than kinh tuan theo quy luat "tat ca hoac khong". Cac xung dong th&n kinh dUdc tao ra se lan ra cac vung xung quanh mang te bao hay doc sdi true tao ra dien the hoat dong d vung ke can, sii lan truyen nay cif tiep tuc nhu vay. Doi vdi sdi than kinh cd bao myelin cac xung dong dan truyen theo kieu "nhay coc" qua cac eo Ranivier nen toe do dan truyen ldn hdn rat nhieu so vdi ca c sdi khong co bao myelin. 4. Cd sd ly thuyet cua phiidng phap ghi dien the kich thich cam giac than the. De tao diidc song SEP, ta kich thich cac sdi hiidng tam cua cd va da hoac triic tiep len day than kinh. Khi kich thich mot day than kinh hon hdp thi xung dong dan truyen 58 theo cac sdi khac nhau deu dupe phong chieu len vo nao. Tren dUdng dan truyen do ta dat cac dien cUc tai cac vi tri khac nhau va se ghi diidc cac dien the khac nhau. Theo phan loai cua Lloyd, cac sdi hudng tam loai la va II co dUdng ki'nh tii 4 - 20|iV gom cac sdi cam giac rung, de ep, cam giac cua sdi thoi cd (sd cap va thti cap), sdi cua thu the Golgi. Cac spi nhom III va IV co dUdng ki'nh nho (gom cac sdi dan truyen cam giac dau va nhiet do) co ngUdng ki'ch thi'ch cao hdn. Khi ki'ch thi'ch day than kinh gitia hoac day than kinh chay sau, ngUdi ta co the ghi dupe rat nhieu song dap Ung cua dien the ki'ch thi'ch tren cac chang dan truyen qua re than kinh (dien the cua re than kinh), qua tuy song (dien the cua tuy song), len cac cau true dUcfi vo (dien the cua cac cau true dudi vo), roi len vo nao (dien the cua vo nao cam giac dac hieu). Cac thanh phan dien the du6i vo co bien do nho nhat (