원저 제주대학교의과대학신경과, 연세대학교의과대학신경과 a 강사윤김승민 a 선우일남 a Clinical and Electrophysiological Characteristics of Leprous Neuropathy Sa-Yoon Kang, M.D., Seung Min Kim, M.D. a, Il-Nam Sunwoo, M.D. a Department of Neurology, College of Medicine, Cheju National University, Jeju Department of Neurology, College of Medicine, Yonsei University a, Seoul, Korea Background: It is important to consider leprosy as a cause of peripheral neuropathy, as it is readily treatable. We analyzed clinical and electrodiagnostic characteristics of leprosy patients with peripheral nerve involvement. Methods: This study was a retrospective analysis of nerve conduction studies (NCS) and the medical records of 10 patients with leprosy were confirmed by a skin or nerve biopsy. NCS using a conventional surface technique were performed in 15 upper extremities and 14 lower extremities. Results: Among ten patients, three patients presented with mononeuropathy, and the others with mononeuropathy multiplex. Five patients had medical histories of leprosy treatment. The patterns of peripheral neuropathies were mononeuropathy multiplex except for one who had an ulnar mononeuropathy. On motor NCS, low or absent CMAPs were most common abnormalities followed by slow conduction velocity and prolonged terminal latency. Sensory NCS also showed changes of amplitudes rather than in conduction velocity. The conduction block of CMAPs with or without dispersion were observed in 5 patients usually on the ulnar nerve at the forearm. Conclusions: In most instances, leprous patients with neuropathy presented with mononeuropathy multiplex affecting the sensory and motor nerves. NCS showed more likely axonal than demyelinating changes, but the conduction blocks were also found frequently at the forearms. J Korean Neurol Assoc 25(2):194-198, 2007 Key Words: Leprosy, Nerve conduction study, Mononeuropathy multiplex, Conduction block 서론 국내에서나병환자의수는점차감소하는추세이나아직도나병은전세계적으로말초신경병증의주요한원인의하나로간주된다. 나병환자에서신경손상은주로체온이낮은표재성말초신경침범을특징으로하나아직까지신경손상의정확한병태생리학적기전은밝혀져있지않다. 또한유행지역에서보 Received December 29, 2006 Accepted February 5, 2007 *Il-Nam Sunwoo, M.D. Department of Neurology, Yonsei University College of Medicine Sinchon-dong, Seodaemun-gu, C.P.O. Box 8044, Seoul, 120-752, Korea Tel: +82-2-361-5461, Fax: +82-2-393-0705 E-mail: sunwooin@yumc.yonsei.ac.kr 고된연구결과에의하면신경전도검사상축삭성병변과국소적인탈수초성병변소견이함께관찰되는것으로알려져있고, 피부병변없이전기생리학적검사에서말초신경병증이관찰되어신경생검을통해나병으로진단된경우가보고되었다. 1,2 따라서나병의진단에서임상소견과함께전기생리학적검사소견이유용한진단도구로이용될수있다. 이번연구의목적은신경및피부조직검사에서나병으로확인된 10명의환자들을대상으로임상적, 전기생리학적특성을규명하고자하는것이다. 대상과방법 1. 대상 194
1992 년부터 2000 년까지신경혹은피부조직검사에서나병으로확인된 10명의환자를대상으로전기생리학적검사및진료기록을후향적으로분석하였다. 나병의진단은신경혹은피부조직의항산균염색에서나균이확인되거나, 육아종과림프구등이관찰되어병리학적으로결핵모양나병으로진단된경우로하였다. 또한병력에서결핵, 당뇨, 매독, 그리고결합조직질환등이확인된경우는제외하였다. 2. 전기생리학적검사신경전도검사는총 15 상지와 14 하지에서시행하였다. 검사는정중신경과척골신경의운동및감각신경과, 비골신경과후경골신경의운동신경, 그리고비복신경의감각신경에서시행하였다. 검사방법및판정기준은세브란스병원신경과전기진단검사실의방법과결과를사용하였다. 3 결과 1. 임상적특성 총 10명의환자중남자는 4명여자는 6명이었으며진단시의연령은 43세에서 76세의분포 ( 평균 51.7 세 ) 를보였다. 내원시임상양상은 3명의환자에서단일신경병증이상을보였고 7명의환자에서다발성신경손상의소견이관찰되었다. 단일신경병증을보인한환자는척골신경손상이의심되었으나감각장애와운동장애의분포가일치하지않았고, 홍반성피부발진이관찰되어피부조직검사를시행하여나균 (leprosy bacillus) 을확인하였다. 다발성신경병증의임상양상을보인 7명의환자는안면과사지에다양한감각증세와운동장애를호소하였고신 경학적검사상비대칭적분포를보였다. 운동장애는 6명의환자에서비대칭적으로수부와수지의마비가, 3명의환자에서는발목마비가현저하였다. 하지만모든환자에서상지와하지의비대칭적인원위부마비가관찰되었다. 운동장애의양상은상지에서는주로척골신경손상이, 하지에서는족저굴곡장애가현저하게관찰되었다. 감각장애는단일신경범위가아닌다발성의국소화된부위에서관찰되었다. 다발성신경손상이관찰된환자들중 6명에서심부건반사는상지와하지에서정상이었고, 한환자에서하지의건반사가감소되어있었다. 증상발생후내원시까지이환기간은 8개월에서 10년으로만성적인경과를보였고 5명의환자에서과거력상나병진단후치료받았던병력이있었다. 내원시나병이의심되었던환자는 4명이었고임상적으로나병의과거력과피부병변, 그리고신경비후 (nerve thickness) 소견이관찰되었다. 나병이외의질환으로의심되었던 6명의환자는피부경화증, 유육종증, 신경초증등으로진단되었으나신경생검에서나병성말초신경병증으로확인되었다. 조직검사에서나균이확인된경우는 2명이었고, 각각피부와신경생검에서관찰되었다 (Table 1). 2. 전기생리학적검사결과신경전도검사상 8예에서다발성단일신경병증의소견이관찰되었고, 나머지 2예에서각각다발신경병증과단일신경병증이상을보였다. 임상적으로 3예에서단일신경병증이의심되었으나 1예에서만단일신경병증소견이확인되었다. 운동신경전도검사상복합근육활동전위의감소나소실이신경전달속도의저하나말단잠복기의지연보다흔한이상소견으로관찰되었고하지에서는후경골신경손상, 상지에서는척골신경손상이많았다. 또한모두 5예에서전도차단 (conduction block) 이 Table 1. Clinical characteristics of 10 patients with leprosy Case Sex Age (y) Presenting symptom Duration Leprosy history Skin lesion Skin biopsy Nerve biopsy 1 F 45 Right ulnar mononeuropathy 2 years No Yes AFB(+) Not done 2 M 60 Multiple mononeuropathy 1 year Yes No Not done Suggestive 3 M 76 Bilateral ulnar neuropathy 8 months Yes Yes AFB(-) Suggestive 4 M 56 Facial sensory changes 9 months Yes No Not done Suggestive 5 F 68 Multiple mononeuropathy 1 year Yes No Not done Suggestive 6 F 51 Multiple mononeuropathy 8 months No Yes Sarcoidosis Suggestive 7 F 46 Both hands weakness 8 years No Yes Scleroderma Suggestive 8 M 43 Right wrist mass 1 year No No Not done AFB(+) 9 F 70 Multiple mononeuropathy 10 years Yes No Not done Suggestive 10 F 46 Left foot drop 2 years No Yes AFB(-) Suggestive AFB; Acid fast bacilli, y; year-old J Korean Neurol Assoc Volume 25 No. 2, 2007 195
강사윤김승민선우일남 나복합근육전위의분산 (dispersion) 이관찰되었는데척골신경이 4예로가장많았고, 정중신경, 후경골신경, 비골신경에서도각각 1예가관찰되었다. 척골신경에서전도차단소견을보인경우는모두전완부 (forearm) 에서관찰되었고특히팔꿈치를중심으로신경전달속도와복합근육활동전위의감소가흔히관찰되어포착성신경병증 (entrapment neuropathy) 환자와의감별이필요하다. 감각신경전도검사상비복신경손상이가장많았고운동신경과마찬가지로신경전달속도의저하보다는활동전위의진폭감소가더현저하였다. 또한정중신경과척골신경에서도활동전위의진폭감소가많았다 (Table 2, 3). 그러나특징적으로근위부인팔꿈치-겨드랑이구간은침범되지않은경우가많았고, 정중신경은 4명그리고척골신경에서는 6명에서근위부침범이관찰되지않았다. 고찰 나병은나균 (Mycobacterium leprae) 에의해발생하는만성적감염질환으로주로피부와표재성말초신경을침범하는것으로알려져있다. 4 비록국내에서는전반적인유병률이감소하는추세이지만아직도서남아시아지역에서는말초신경병증의주요한원인으로남아있다. 나병은나균에대한환자의면역반응에따라다양한임상양상으로표현되는데주로나종모양나병 (lepromatous leprosy) 과결핵모양나병 (tuberculoid leprosy) 으로나눌수있다. 본연구에서생검상 2예에서나균이발견되었지만임상적으로전형적인나종모양나병의양상은관찰되지않았다. 또한나균이발견된 2예중한환자에서만홍반성발진과신경비후가관찰되어임상적진찰만으로나병을초기에진단하는데어려움이있다. 피부병변없이말초신경만침범될수있는데이러한경우결핵모양나병환자에서주로나타나고신경생검이진단에도움을줄수있다. 2,5,6 본연구대상 10명중 4명에서도피부병변이나신경비후가관찰되지않은것을볼때, 비록나병환자에서피부홍반성발진과신경 Table 2. Nerve conduction abnormalities in 15 arms of leprosy subjects Nerve conduction test Number of abnormal nerves Nerve conduction test Number of abnormal nerves Ulnar sensory Ulnar motor Absent response 6 Absent response 3 Small amplitude 0 Small amplitude 5 Slow NCV 3 Slow NCV 2 Prolonged latency 2 Conduction block 4 Median sensory Median motor Absent response 6 Absent response 1 Small amplitude 0 Small amplitude 4 Slow NCV 4 Slow NCV 5 Prolonged latency 4 Conduction block 1 NCV; nerve conduction velocity Table 3. Nerve conduction abnormalities in 14 legs of leprosy subjects Nerve conduction test Number of abnormal nerves Nerve conduction test Number of abnormal nerves Peroneal motor Posterior tibial motor Absent response 4 Absent response 4 Small amplitude 3 Small amplitude 3 Slow NCV 2 Slow NCV 4 Prolonged latency 1 Prolonged latency 2 Conduction block 1 Dispersion 1 Sural nerve Absent response 12 Small amplitude 0 Slow NCV 0 NCV; nerve conduction velocity 196
비후가가장흔한이학적소견으로알려져있지만진단에특이적인소견은아닌것으로생각된다. 따라서만성적인경과를보이고신경전도검사에서다발성단일신경병증이관찰되는경우나병성말초신경병증의감별을위해신경생검을시행하는것이필요하다. 일반적으로국소적감각장애를주소로내원하는경우가많았는데실제로신경학적검사에서는환자의주증상부위이외의다른영역에서도감각장애가관찰되었고, 진찰소견이불충분한한환자를제외하고모든환자에서운동장애가동반돼서보다넓은부위에서말초신경계의손상이진행되었음을알수있었다. 따라서나병환자에서는임상징후의출현이전에도신경전도검사를통해신경손상을확인할수있으므로신경전도검사는나병의진단에유용한검사방법으로생각된다. 운동장애보다는감각장애가더현저한것으로보고되고있으며감각장애는주로촉각과통증감각의소실이흔한것으로알려져있으나, 자세한신경학적검사를시행하면감각장애가있는경우에대부분말단부운동장애가동반되어있는것을관찰할수있다. 7,8 그리고표재성신경에비해심부에위치한굵은유수신경은비교적보존되는것으로알려져있고이로인해광범위한말초신경계의침범징후에도불구하고건반사는소실되지않는것이특징이라할수있다. 4 본연구대상환자에서도건반사가비교적보존되어있는것이관찰되어임상적으로유의한소견으로생각된다. 나병에서신경손상의기전은매우다양한것으로알려져있고아직확립되지못한것이사실이다. 말초신경의침범은나종모양나병보다는결핵모양나병에서더많고또한특정신경이다른신경에비해흔히침범되는것으로알려져있다. 4,8,9 본연구에서도임상적및전기생리학적검사에서척골신경손상이가장많은것으로밝혀졌고척골운동신경전도검사상전완부에서특히팔꿈치를중심으로신경전달속도와복합근육활동전위의감소가흔히관찰되었는데, 이는다른연구결과들과일치하는소견이다. 7,8,10 척골신경침범이팔꿈치부위에서많은이유로는우선표재성으로위치하여주위온도가낮고, 이로인해나균의침윤이용이한환경을제공하며, 반복적인외상과주위상관절융기 (epicondyle) 와의충돌 (impingement) 등이복합적으로작용하는것으로생각된다. 이전의연구에서하지에서는주로비골신경침범이흔한것으로알려져왔으나본연구에서는임상적으로족저굴곡장애가더현저하였고신경전도검사에서도비골신경보다는후경골신경손상이더흔하게관찰된점이특징적인소견이다. 본연구에서신경전도검사상가장많은유형은다발성단일신경병증으로이는피부혹은신경생검에서나균이검출된경 우보다는결핵모양나병양상의소견이흔히관찰되어환자의나균에대한면역반응과관련된것으로생각된다. 그리고운동신경과감각신경전도검사모두에서전달속도의저하보다는활동전위의소실이나감소가주요한이상소견으로관찰되었다. 이러한결과는이전에보고된연구와일치하는소견으로나병성말초신경병증이주로축삭손상에의한것으로생각된다. 1,7,11,12 또한근전도검사를시행한 3예중 2명에서탈신경성전위 (denervation potentials) 가관찰된것이이러한사실을뒷받침한다. 비록연구대상환자의수가적고병의이환기간과의관련성을고려해야하지만 1년이내의병력을갖는환자에서도축삭성신경병증소견이관찰된점은의미가있다고할수있다. 하지만 5명의환자에서관찰된전도차단이나분산소견은탈수초성말초신경질환의특징으로나병성말초신경병증이단지축삭성말초신경질환으로분류될수없음을시사한다. 1980 년대에는나병성말초신경병증이전달속도의저하를특징으로하는탈수초성말초신경질환으로분류되었으나최근연구들에의하면질환초기에는오히려활동전위의감소가더특징적인소견이라고보고되고있다. 7,13 따라서나병성말초신경병증은축삭손상과탈수초성병변이혼합된말초신경질환으로분류하는것이적합하다고생각된다. 저자들은신경혹은피부생검에서나병으로확인된 10명의환자들을대상으로임상적및전기생리학적소견을분석하였으며다음의결론을얻었다. 임상적으로만성적인경과를보이고국소적인신경학적결손이나타나며신경전도검사상임상증상과관계없이다발성단일신경병증의양상을보이며, 주로축삭성병변과함께전완부에서전도차단이나복합근육활동전위의분산이관찰되는환자에서는나병성말초신경병증의가능성을고려하여야할것이다. REFERENCES 1. Ramakrishnan AG, Srinivasan TM. Electrophysiological correlates of hanseniaisis. Int J Lepr Other Mycobact Dis 1995;63:395-408. 2. Skacel M, Antunes SL, Rodrigues MM, Nery JA, Valentim VD, Morais RP, et al. The diagnosis of leprosy among patients with symptoms of peripheral neuropathy without cutaneous lesions: a follow-up study. Arq Neuropsiquiatr 2000;58:800-807. 3. Lee KY, Kim WK, Kwon SH, Cho TY, Lee SH, Cheong KH, et al. The usefulness of standardization of the nerve conduction study in the diagnosisand follow up of the demyelinating polyneuropathy. J Korean Neurol Assoc 1998;16:510-518. 4. Nations SP, Katz JS, Lyde CB, Barohn RJ. Leprous neuropathy: an American perspective. Semin Neurol 1998;18:113-124. 5. Rodriguez G, Sanchez W, Chatela JG, Soto J. Primary neuritic leprosy. J Am Acad Dermatol 1993;29:1050-1052. J Korean Neurol Assoc Volume 25 No. 2, 2007 197
강사윤김승민선우일남 6. Jenkins D, Rapp K, Jakubovic HR, Shiffman N. Leprotic involvement of peripheral nerves in the absence of skin lesions. Case report and literature review. J Am Acad Dermatol 1990;23:1023-1026. 7. Brown TR, Kovindha A, Wathanadilokkol U, Piefer A, Smith T, Kraft GH. Leprosy neuropathy: correlation of clinical and electrophysiological tests. Indian J Lepr 1996;68:1-14. 8. Ramadan W, Mourad B, Fadel W, Ghoraba E. Clinical, electrophysiological, and immunopathological study of peripheral nerves in Hansen s disease. Lepr Rev 2001;72:35-49. 9. Mshana RN, Humber DP, Harboe M, Belehu A. Demonstration of mycobacterial antigens in nerve biopsies from leprosy patients using peroxidase-antiperoxidase immunoenzyme technique. Clin Immunol Immunopathol 1983;29:359-368. 10. Kaplan M, Gelber RH. Evaluation of testing modalities for peripheral neuropathy in lepromatous Hansen s disease. Phys Ther 1985;65:1662-1665. 11. DeFaria CR, Silva IM. Electromyographic diagnosis of leprosy. Arq Neuropsiquiatr 1990;48:403-413. 12. Tzourio C, Said G, Millan J. Asymptomatic nerve hypertrophy in lepromatous leprosy: a clinical, electrophysiological and morphological study. J Neurol 1992;239:367-374. 13. Donofrio PD, Albers JW. AAEM minimonograph #34: polyneuropathy: Classification by nerve conduction studies and electromyography. Muscle Nerve 1990;13:889-903. 198