대한내과학회지 : 제 91 권제 3 호 2016 http://dx.doi.org/10.3904/kjm.2016.91.3.267 Interpretation of diagnostic test 손목굴증후군 건국대학교의학전문대학원 1 내과학교실류마티스내과, 2 신경과학교실 김해림 1 오지영 2 Carpal Tunnel Syndrome Hae-Rim Kim 1 and Jeeyoung Oh 2 Division of Rheumatology, Departments of 1 Internal Medicine and 2 Neurology, Konkuk University School of Medicine, Seoul, Korea Carpal tunnel syndrome (CTS) is a common entrapment neuropathy caused by compression of the median nerve at the wrist. Although symptoms and signs of CTS are widely known, it is often difficult to make a correct diagnosis. A clinical examination, electrophysiological studies, and ultrasonographic evaluation have similar sensitivities and specificities, and combining them improves diagnostic yield. However, evidence about the optimal treatment has not been well established. We review the clinical manifestations, diagnostic methods, and treatment options for CTS. (Korean J Med 2016;91:267-272) Keywords: Carpal tunnel syndrome; Ultrasonography; Nerve conduction 서론손목굴증후군 (carpal tunnel syndrome) 은정중신경이손목에서압박되어나타나는포착신경병 (entrapment neuropathy) 으로보통전생애에걸쳐약 10% 정도인구에서발생할정도로흔하다 [1]. 손목굴은손목주름에서 2.0-2.5 cm 원위부에위치한좁은굴모양의구조로주상골 (scaphoid), 소능형골 (trapezoid), 갈고리뼈 (hamate) 와가로손목인대 (transverse carpal ligamanet) 에둘러싸여있다 [2]. 이구조물안으로정중신경과손가락굽힘근의인대가주행한다. 임신, 부종, 건염, 당뇨, 갑상선기능저하나반복적인수작업등에의해손목굴안의압력이지속적으로상승하게되면정중신경이압박되고이로인해손목굴증후군이발생한다. 체질량지수가높을때 나손의크기가작은경우, 손목의전후직경이큰경우에도손목굴증후군이더호발한다 [3]. 손목굴증후군은흔한질환임에도불구하고진단이나치료에대한특정한가이드라인이많지않아임상경험에의존하는경우가많고, 다른질환과감별도쉽지않은경우도있다. 본고에서는손목굴증후군의다양한임상증상과이를정확히진단하기위한검사도구, 치료방향에대한실제적인내용을다루고자한다. 임상양상전형적인증상은엄지, 검지, 중지와약지반에걸쳐나타나는손가락통증이며, 주무르거나손을털면저린감이완화되고밤에증상이더심해져깨는경우가많다. 그러나통증 Correspondence to Jeeyoung Oh, M.D., Ph.D. Department of Neurology, Konkuk University School of Medicine, 120-1 Neuongdong-no, Kwangjin-gu, Seoul 05030, Korea Tel: +82-2-2030-7564, Fax: +82-2-2030-5169, E-mail: serein@kuh.ac.kr Copyright c 2016 The Korean Association of Internal Medicine This is an Open Access article distributed under the terms of the Creative Commons Attribution - 267 - Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
- The Korean Journal of Medicine: Vol. 91, No. 3, 2016 - 이전완부로방사되거나심지어어깨부위까지통증을호소하는경우도흔해서경추신경뿌리병과감별이어려울때도있다. 고개를돌릴때악화되는통증이나저린감이있으면척추질환의가능성이더높지만, 경추신경뿌리병과손목굴증후군이동시에나타나는경우 (double crush injury) 도있다. 또단순한건초염 (tenosynovitis) 에서도손목굴증후군과유사한증상이나타날수있는데방아쇠손가락 (trigger finger) 이나윤활낭염 (bursitis) 이동반되는경우가흔하다. 자율신경섬유가함께침범되면혈관운동반사 (vasomotor reflex) 가손상되어레이노증후군과유사한증상이나타나며이는류마티스관절염과같은전신질환이있는경우더흔하다. 손가락감각이둔해지면물건을잡고있다가놓치는경우도흔히발생하며, 증상이심해져엄지두덩근이위축되면손가락운동도둔해지게된다. 진단임상진단전형적인증상만으로도진단이가능한데, 몇가지진찰이보다진단의정확도를높일수있다. 손목을 90도로꺾어양손등을맞대고있으면 (Phalen test) 약 1분내에평소와같은저린감이나통증이유발되고, 이상태에서손을가볍게쥐면통증이소실된다 [4]. Tinel 징후는재생중인신경섬유의탈분극역치가낮아생기는현상으로가볍게신경주행경로를두드릴때신경이지배하는영역으로저린감이나타나는것을말한다. 손목굴증후군에서는손목주위를해머로가볍게두드리거나검사자의손으로누를때손끝으로저린감을호소하게된다. 감각신경검사에서전형적인이상소견을보이는경우는생각보다많지않지만, 정중신경의감각신경분지가지배하는엄지, 검지, 중지와약지의반에서통각이나촉각이둔하고, 특히약지의내측과외측의감각이서로다를때는손목굴증후군의가능성이매우높다. 한편엄지두덩을지배하는감각신경은손목굴 3 cm 상부에서분지하기때문에손목굴증후군에서는엄지두덩의감각은정상이어야한다. Carpal Tunnel Syndrome 6 (CTS-6) 는진단을용이하게하고자여섯개의주요증상을점수화한것으로항목은정중신경영역에국한되거나주로나타나는감각이상, 밤에악화되는증상, 엄지두덩의근위축이나근위약, Phalen 테스트양성, 두점식별감각소실, Tinel 징후양성으로구성된다. 총 36점중 12점이상인경우손목굴증후군으로진단할수있는 데민감도 60%, 특이도 90% 로보고되었다 [5] (Table 1). 초음파검사 초음파검사는손목굴증후군에서진단적가치가매우높다. 신경전도검사에서이상이발견되지않는초기손목굴증후군의진단은물론 [6], 주위조직을함께볼수있으므로구조적이상도함께확인할수있는장점이있다 [7,8]. 정중신경이손목굴의근위부에서는종창이, 중간부와원위부에서는압박이생기므로이러한특징적인병변이초음파로잘관찰된다. 정중신경의정상소견은세로스캔에서두께가일정하고, 주변힘줄에비해서에코가낮으나균질적인실타래모양을보이고주변과의경계가뚜렷하다 (Fig. 1A). 가로스캔에서가로손목인대, 고에코성경계를갖는타원형모양의정중신경, 8개의손목굽힘근들이관찰한다 (Fig. 1B). 손목굴증후군을평가할때먼저세로스캔으로정중신경의전체적인주행을관찰하는데손목굴근위부 (proximal carpal tunnel, tunnel inlet) 에서정중신경의종창에의해두께가오히려증가하고, 원위부 (distal carpal tunnel, tunnel outlet) 에서는압박이되며, 에코가감소하며, 경계의명확성이소실된다 (Fig. 1C). 근위부손목굴의가로스캔에서먼저콩알뼈 (pisiform) 와손배뼈 (scaphoid) 를가로지르는가로손목인대를찾고, 그아래를지나는정중신경의단면적을측정하여, 10-11 mm 2 이상인지여부가진단에가장중요하다 (Fig. 1D). 그후원위부손목굴을가로스캔하여 ( 갈고리뼈가기준점 ) 정중신경의가로길이가세로길이의비율 (flattening ratio) 이 3배이상이면압박이있는것을의미한다. 또한손목굴의압력이증가되어가로손목인대가손바닥방향으로휘어있는지 (palmar bowing) 를확인한다 (Fig. 1E). 마지막으로정중신경자체의이상이나신경을압박할다른병변의존재여부를확인한다. 신경전도검사 신경전도검사는신경의손상정도를정량화하여평가할 Table 1. Carpal Tunnel Syndrome-6 Finding Numbness predominantly or exclusively in the median nerve area Nocturnal symptoms Thenar atrophy or weakness Positive Phalen test Loss of 2-point discrimination (> 5 mm) Positive tinel sign Points 3.5 4 5 5 4.5 4-268 -
- Hae-Rim Kim, et al. Carpal tunnel syndrome - 수있고, 손목굴증후군과유사한양상을보이는다른질환을감별하는데도움이된다. 운동신경과감각신경을각각검사하는데, 감각신경의변화가더먼저나타난다. 초기에는손가락- 손목구역에서감각신경전달속도가느려지고축삭변성이진행하게되면감각신경전위의진폭이감소한다. 정상운동신경전도와비교하여 (Fig. 2A) 운동신경전도검사에서는말단잠시 (terminal latency) 가연장되고단무지외전근 (abductor pollicis brevis muscle) 이위축되면복합운동활동전위진폭도감소하게된다 (Fig. 2B). 신경손상이심한경우에는활동전위가유발되지않는경우도있다 (Fig. 2C). 증상 A B C D E 의초기에는일상 (routine) 신경전도검사에서이상을보이지않기도하는데, 이런경우에는손바닥구역에서정중신경과척골신경 (ulnar nerve) 의감각신경전도검사를시행하여잠시 (latency) 를비교하면도움이된다 [8,9]. 침근전도검사는운동신경분지의침범여부를확인하거나신경뿌리병과의감별에도움을주지만모든환자에게추천되지는않는다. 전기진단검사결과에따라중등도를결과지에표기하는데 (Table 2) 검사실에서어떤기준을사용하느냐에따라약간다르나축삭변성이동반되는경우는중증으로볼수있다 [10,11]. 환자의증상과전기진단검사의중등도가반드시일치하지는않아중등도표기에논란이있고실제치료방향을결정하는데도환자의주관적인증상이더중요한인자가되지만수술후예후를예측하는데는도움이된다는보고들이있다 [12]. 전형적인증상이있음에도불구하고신경전도검사에서이상소견이발견되지않는경우도있는데, 충분한신경섬유의변성이일어나지않은질병초기에검사를하거나가는신경섬유만침범되어신경전도검사로는발견이안되는경우로생각할수있다 [13,14]. 또신경종 (neuroma) 이나주위조직염증에의해정중신경이단순히자극되어나타나는경우에도신경전도검사가정상일수있어서의심되는경우에는초음파검사를함께시행하는것이좋다 [6,15]. 반대로손목굴증후군의증상은모호하나신경전도검사에서손목부위의정중신경병 (median motor neuropathy at the Table 2. Carpal tunnel syndrome severity grade according to nerve conduction study results Figure 1. Ultrasonographic findings of a normal carpal tunnel and a carpal tunnel with carpal tunnel syndrome. (A) Longitudinal scan shows normal median nerve with regular fibrillary pattern and unchanging thickness surrounded by a hyperechoic boundary in the carpal tunnel. (B) Transverse scan of the proximal carpal tunnel shows transverse carpal ligament (arrows), the oval-shaped median nerve, which is located in the superficial part of the carpal tunnel, and the flexor digitorum superficialis and profundus tendons in the deeper part of the carpal tunnel. In carpal tunnel syndrome, (C) the median nerve is compressed in the middle and distal carpal tunnel (arrows) on a longitudinal scan; (D) cross-sectional area of median nerve increases > 10 mm 2 in the proximal carpal tunnel and (E) the flattening ratio (longest diameter: shortest diameter of median nerve) is > 3:1 in the distal carpal tunnel. MN, median nerve; P, pisiform; TCL, transverse carpal ligament (arrows); FCR, flexor carpi radialis tendon; SC, scaphoid Grade Description Normal (grade 0) All nerve conduction study results are within normal limits Very mild (grade 1) Only within-hand sensory comparison study results are abnormal Mild (grade 2) Median sensory distal latency prolonged; DML is within normal limits Moderate (grade 3) Median SNAP is recordable; median DML is prolonged but < 6.5 ms Severe (grade 4) Median SNAP is unrecordable; median DML is prolonged but < 6.5 ms Very severe (grade 5) Median CMAP is recordable but DML is > 6.5 ms Extremely severe Median CMAP is essentially unrecordable (grade 6) DML, distal motor latency; SNAP, sensory nerve action potential; CMAP, compound motor action potential. - 269 -
- 대한내과학회지 : 제 91 권제 3 호통권제 673 호 2016 - A B C Figure 2. Compared with a normal motor nerve conduction study (A), results of carpal tunnel syndrome show delayed terminal latency (B, arrow) with no sensory nerve action potential at the finger-wrist segment (C, arrowhead). wrist) 소견을보이는경우에는주의해야한다. 원인은아직명확하지않지만단순한비만에의해서도발생하고, 만성염증탈수초다발신경뿌리병 (chronic inflammatory demyelinating polyradiculoneuropathy) 이나파라단백질과연관된신경병 (pareproteinemic neuropathy), 드물게는아밀로이드신경병이나파브리병의일환으로나타나는경우에잘못진단되면불필요한수술을받거나적절한치료가늦어질수있으므로전기진단검사결과는반드시임상증상과상관되는지확인해야한다. 치료비수술치료비수술적치료는진행을억제한다기보다는일시적으로증상을경감시키는효과가더크다. 국소스테로이드주사는부종을가라앉히고손목굴에서정중신경의압박을경감하는역할을한다. 초음파로신경을확인하면서주사하는것이더안전하고효과적이며 [16] 손바닥에서손목부위를향해주사하는방법이환자에게통증을덜느끼게하는방법이다. 대개 methylprednisolone 40 mg 혹은 80 mg을주사하며, 두용량모두증상완화효과는비슷하나 80 mg 주사군에서 1년후수술받는환자수가더적었다 [17]. Triamcinolone이나 procaine hydrocholoride를주사하기도한다. 손목굴증후군에서나타나는통증도신경병통증이므로경구약물로대증치료가가능하나실제임상연구는많지않 다. Gabepentin을투약한임상연구에서통증, 저린감, 근위약등의증상이위약대비효과적이지못했다. 그러나실제임상에서국소주사와병행해서혹은국소주사나수술치료를거부하는환자에게는통상의신경병통증약물을단기간투약할수있다. Gabapentin 과 pregabalin 은손목굴증후군상병으로는보험급여가되지않지만, 당뇨신경병과함께발생한경우에는급여가가능하다. 시작용량은 gabapentin 100 mg 하루 3회혹은 pregabalin 75 mg 2회이나고령이나신기능이저하된경우는더적은용량으로시작한다. 두약제는각각하루 3,600 mg과 600 mg이최대용량으로효과와부작용에따라투여용량과횟수를증감한다. 손목의과굴곡을막아부종을줄이기위해손목부목 (splint) 을착용하는방법도있다. 8주간부목을착용한환자군에서그렇지않은경우에비해손의기능이호전되고증상이완화된결과를보였다 [18]. 그러나메타분석에서는충분한효과를입증하기어려웠고증상의호전도일시적이라는연구보고도있다 [1]. 그외침, 물리치료등의일차적효과와수술후보조요법에대해서는충분한연구가부족해아직단정하기어렵다 [19]. 수술치료가로손목인대를절단해서손목굴안의압력을완화하는방법으로가장근본적이고효과적인치료라고할수있다. 손바닥피부를절개해서육안으로인대를확인하고절단하는방법 (open technique) 과내시경을이용하는방법이있다. - 270 -
- 김해림외 1 인. 손목굴증후군 - 내시경수술은상처부위가작기때문에수술후압통과움직임제한이덜해회복기간이짧은반면수술중신경손상의위험이개방술에비해상대적으로높다. 어떤술기를사용하더라도가로손목인대를완전히절개하도록권유하고있으며 [20], 이런경우장기추적에서양수술방법사이에효과는차이가없는것으로나타났다. 수술합병증은집도의의술기에따라다르지만 1-25% 에서보고되며가장심각한것은신경의직접적인손상이나주위조직손상에따른복합부위통증증후군 (complex regional pain syndrome) 으로약 2.1-5% 에서발생한다 [1]. 국소스테로이드주사에비해수술치료가장기적인증상개선에더효과적이고신경전도검사결과에서도더나은반응을보이므로, 비수술치료에도불구하고통증이지속되거나운동신경침범에의해손의기능이떨어진경우에는수술치료를고려할수있다. 결 손목굴증후군은임상에서흔히볼수있고간단한방법으로진단과치료가가능하지만일부환자에서는경추신경뿌리병이나척수병혹은다른말초신경병과감별이어려운경우도있다. 통증이나이상감각의분포는진단에큰도움은되지않으나 Phalen test 양성, Tinel 징후, 손을쥐었을때통증이완화되는진찰소견을보이면손목굴증후군을의심할수있고, 신경전도검사와초음파검사로신경손상의정도와구조적이상을확인할수있다. 환자의증상과상태에따라국소스테로이드주사나수술치료로신경기능을초기에회복시켜주는것이중요하며, 그외치료방법에대해서는아직더많은연구가필요하다. 론 중심단어 : 손목굴증후군 ; 초음파 ; 신경전도 REFERENCES 1. Padua L, Coraci D, Erra C, et al. Carpal tunnel syndrome: clinical features, diagnosis, and management. Lancet Neurol 2016;15:1273-1284. 2. Chammas M, Boretto J, Burmann LM, et al. Carpal tunnel syndrome - Part I (anatomy, physiology, etiology and diagnosis). Rev Bras Ortop 2014;49:429-436. 3. Henry BM, Zwinczewska H, Roy J, et al. The prevalence of anatomical variations of the median nerve in the carpal tunnel: a systematic review and meta-analysis. PLoS One 2015;10:e0136477. 4. Manente G, Torrieri F, Pineto F, Uncini A. A relief maneuver in carpal tunnel syndrome. Muscle Nerve 1999;22:1587-1589. 5. Fowler JR, Cipolli W, Hanson T. A comparison of three diagnostic tests for carpal tunnel syndrome using latent class analysis. J Bone Joint Surg Am 2015;97:1958-1961. 6. Koyuncuoglu HR, Kutluhan S, Yesildag A, Oyar O, Guler K, Ozden A. The value of ultrasonographic measurement in carpal tunnel syndrome in patients with negative electrodiagnostic tests. Eur J Radiol 2005;56:365-369. 7. Azami A, Maleki N, Anari H, Iranparvar Alamdari M, Kalantarhormozi M, Tavosi Z. The diagnostic value of ultrasound compared with nerve conduction velocity in carpal tunnel syndrome. Int J Rheum Dis 2014;17:612-620. 8. Goldberg G, Zeckser JM, Mummaneni R, Tucker JD. Electrosonodiagnosis in carpal tunnel syndrome: a proposed diagnostic algorithm based on an analytic literature review. PM R 2016;8:463-474. 9. Jablecki CK, Andary MT, Floeter MK, et al. Practice parameter: electrodiagnostic studies in carpal tunnel syndrome. Report of the American Association of Electrodiagnostic Medicine, American Academy of Neurology, and the American Academy of Physical Medicine and Rehabilitation. Neurology 2002;58:1589-1592. 10. Bland JD. A neurophysiological grading scale for carpal tunnel syndrome. Muscle Nerve 2000;23:1280-1283. 11. Werner RA, Andary M. Electrodiagnostic evaluation of carpal tunnel syndrome. Muscle Nerve 2011;44:597-607. 12. Fowler JR, Munsch M, Huang Y, Hagberg WC, Imbriglia JE. Pre-operative electrodiagnostic testing predicts time to resolution of symptoms after carpal tunnel release. J Hand Surg Eur Vol 2016;41:137-142. 13. Al-Hashel JY, Rashad HM, Nouh MR, et al. Sonography in carpal tunnel syndrome with normal nerve conduction studies. Muscle Nerve 2015;51:592-597. 14. Żyluk A, Walaszek I, Szlosser Z. No correlation between sonographic and electrophysiological parameters in carpal tunnel syndrome. J Hand Surg Eur Vol 2014;39:161-166. 15. Rahmani M, Ghasemi Esfe AR, Vaziri-Bozorg SM, Mazloumi M, Khalilzadeh O, Kahnouji H. The ultrasonographic correlates of carpal tunnel syndrome in patients with normal electrodiagnostic tests. Radiol Med 2011;116:489-496. 16. Evers S, Bryan AJ, Sanders TL, Selles RW, Gelfman R, Amadio PC. The effectiveness of ultrasound-guided compared to blind steroid injections in the treatment of carpal tunnel syndrome. Arthritis Care Res (Hoboken) 2016 Oct 1 [Epub]. http://dx.doi.org/10.1002/acr.23108. 17. Lyon C, Syfert J, Nashelsky J. Clinical inquiry: do corticosteroid injections improve carpal tunnel syndrome symptoms? J Fam Pract 2016;65:125-128. - 271 -
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