05-05 박수성(국)

ORIGINAL ARTICLE http://dx.doi.org/10.5371/hp.2012.24.4.295 Print ISSN 2287-3260 Online ISSN 2287-3279 MRI in Suspected Acute Septic Arthritis of the Hip Joint in Children Soo-Sung Park, MD, PhD, Soo-Ho Lee, MD, PhD, Gyeong-Bo Sim, MD Department of Orthopaedic Surgery, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea Purpose: The purpose of this study is to assess the usefulness of magnetic resonance imaging (MRI) in diagnosis, planning of treatment methods for suspected acute septic arthritis in children, and evaluation of the clinical results of the operations with the help of magnetic resonance imaging as a diagnostic modality. Materials and Methods: Between March 2003 and May 2007, 20 patients suspected of having acute septic arthritis of the hip underwent MRI. The mean age of the patients was 3 years and 5 months (range: 10 days-14 years). The average follow-up was 2 years and 2 months (range: 1 year-3 years 6 months). Assessment of MRI findings and final results with recurrence of the infection and post-infectious radiographic sequelae was performed retrospectively. Results: Among the 20 cases, 17 cases(85%) showed joint effusion. Among these 17 cases, accompanying signal changes were observed in the meta-epiphyseal region in seven cases, and accompanying signal changes were observed in surrounding soft tissue in three cases. Accompanying abscess formation was observed in one case. The remaining three cases(15%), which had no joint effusion, showed an intramuscular abscess pocket around the joint, which mimicked septic arthritis. At final follow up, two cases showed unsatisfactory results, with limited joint motion and radiographic sequelae. Conclusion: In children who are suspected of having acute septic arthritis of the hip, MRI can provide useful information about the location and extent of infection and even the differential diagnosis of acute septic arthritis. MRI was considered to be a useful method for diagnosis of suspected acute septic arthritis in children. Key Words: Children, Septic hip arthritis, MRI Submitted: August 21, 2012 1st revision: October 18, 2012 2nd revision: November 8, 2012 3rd revision: November 23, 2012 Final acceptance: November 26, 2012 Address reprint request to Gyeong-Bo Sim, MD Department of Orthopaedic Surgery, Asan Medical Center, Ulsan University College of Medicine, Asanbyeongwon-gil 86, Songpagu, Seoul 138-736, Korea TEL: +82-2-3010-0834 FAX: +82-2-488-7877 E-mail: alert79@hanmail.net This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons. org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 서 론 급성화농성고관절염이의심되는소아의경우, 신속한진단을내린후이에따른적절한치료를해야하는것이매우중요하다. 소아기의급성화농성고관절염에서조기에정확한진단과치료가이루어지지않을경우골단부괴사, 성장판손상으로인한변형및관절탈구, 패혈증등여러가지심각한합병증이발생할수있다 1,2). 특히화농성고관절염이골수염과동반된경우관절내의감염병소외에골수내의감염병소를적절히치료하는것이감염의재발방지나성장판을포함한골조직의파괴를방지하기위해꼭필요한치료과정이다. 임상적소견이나검사소견상급 Copyright c 2012 by Korean Hip Society 295

성화농성고관절염이의심되는경우, 일과성활액막염이나 Legg-Calve-Perthes 병, 류마토이드관절염등의초기에비수술적치료를요하는질환외에골수염이나관절주변근육내농양등의관절외감염증등조기에수술적치료가필요한질환들도감별하여야하는데 3-5), 자기의사표현능력이부족한소아에서정확한병력청취나이학적검사가힘들며혈액검사, 단순방사선검사및관절천자검사로도정확한진단을내리기어려운경우가많다. 이러한소아의특성을고려해자기공명영상검사가임상에서실제로많이시행되고있다. 본연구의목적은소아에있어서급성화농성고관절염의진단과그에따른치료방법의선택에있어자기공명영상의유용성과임상결과를평가하고자하였다. 대상및방법 2003년 3월부터 2007년 5월까지임상소견과검사소견상급성화농성고관절염이의심되어자기공명영상을시행한후수술을시행하고, 1년이상추시관찰이가능하였던 15세미만의소아환자 20명을연구대상으로하였다. 평균추시기간은 2년 2개월 ( 범위 : 1년-3년 6개월 ) 이었다. 전체 20예를대상으로증상발현후수술까지의경과시간을비롯한환자의병력, 임상증상, 진찰소견, 혈액검사, 관절천자검사와균주배양검사외에단순방사선및자기공명영상소견을분석하고, 이에따른병소의정확한위치에따라수술방법을결정한후에수술을시행하고, 임상적결과를후향적으로분석하였다. 수술당시평균연령은 3년 5개월 ( 범위 : 10일-14세 ) 이었으며, 남자가 11명, 여자가 9명이었다. 병력, 임상증상, 진찰및검사소견상첫번째로 38 C 이상의발열, 두번째로관절부종및국소열감, 관절자극증상, 세번째로혈액검사상의백혈구수치가 10,000/mm 3 이상, 네번째로적혈구침강속도 (ESR) 가 40 mm/hr이상 ( 정상치 ; 0-20 mm/hr), 다섯번째로 C반응단백 (C-reactive protein) 이 1 mg/dl 이상 ( 정상치 ; 0-0.6 mg/dl) 인다섯가지소견중세가지이상이해당되는경우관절의급성감염증이의심되는환자로판단하고자기공명영상검사를시행하였다. 자기공명영상소견은해당관절의삼출액, 골단및골간단부등골조직의신호강도변화또는농양형성, 관절주변근육등연부조직의신호강도변화나농양형성유무를조사하였다. 자기공명영상소견에따른농양의위치에따라수술도달법과방법을결정한후에수술을시행하였다. 수술방법으로는관절강내에병소가있으면절개및배농술과세척술, 골조직에침범하였으면다발성골천공술또는골소파술을동시에시행하였다. 관절주변근육내에농양이위치한경우에는관절절개술을시행하지않고해당근육내농양의절개및배농술, 변연절제술등을시행하였다. 자기공명영상소견에서발견된병소는수술시에모두확인후 배농하였으며약 4 주간의항생제치료를병용하는것을원칙으로하였다. 결 과 1. 임상적특성 환자들은모두에서관절주변의동통, 관절운동제한및해당관절의수동적운동시관절자극증상등을호소하였고그외에 5예에서종창이, 전례에서압통과국소열이, 6 예에서전신발열등을보였다. 내원시체온은평균 38.0 C ( 범위 : 36.7-39.7 C) 였고, 38 C 미만이 14예, 38 C 이상이 6예였다. 말초혈액내백혈구수는평균 12.0 103/mm 3 ( 범위 : 8.4-17.3 103/mm 3 ) 이었으나범위는다양하였으며 10.0 103/mm 3 이하인경우도 4예 (20%) 가있었다. 적혈구침강속도 (ESR) 를시행한 12예의평균치는 65.9 mm/hr( 범위 : 19-130 mm/hr) 이었고 C반응단백 (Creactive protein) 은전례에서시행하였고평균 7.5 mg/dl ( 범위 : 0.2-16.3 mg/dl) 이었다. 적혈구침강속도 (ESR) 가정상인경우는이검사를시행한 12예중 1예였으며 C반응단백의수치가정상인경우는 2예였다. 발병장소는 16예가집이었으며, 3예는병원에서증상이발현하였고 1예에서는한의원에서침을맞은병력이있었다. 수술적치료전관절천자술을총 20예중 4예는관절주위연부조직의염증소견이의심되어시행하지않았고, 나머지 16예중협조가불가하였던 2예, 장근과요근의근육내농양으로관절내삼출액이없었던 2예를제외한나머지 12예에서관절삼출액을검출할수있었으나, 이중 4예는검체의양이부족하여검사를진행하지못하였다. 남은 8예중 7예에서만균검사및배양검사에서양성소견을보였다. 증상발현에서진단까지의기간은평균 7일 ( 범위 : 1-21일 ) 이었다. 2. 방사선학적소견 단순방사선소견상해당관절의아탈구및골단및골간단부의골융해성병변등이상소견을보인경우는없었으며자기공명영상소견상으로는대부분의예인 17 예 (85%) 에서관절삼출액증가가있었던반면 (Fig. 1), 3 예 (15%) 에서는해당관절의관절내삼출액의증가소견이없이관절주변의근육내에농양이위치하고있어서급성화농성관절염과유사한임상증상을일으킨것으로추측되었다. 이환된근육으로는내전근 (Fig. 2), 요근 (Fig. 3) 등이었고, 근육내농양이있었던 3 명의환자의경우발열, 관절자극증상등의임상증상외에혈액검사상염증지수가증가되는등고관절의급성화농성관절염과증상이유사하였다. 관절삼출액이증가되어있었던 17 예중골단이나골간단부의신호강도변화가동반되었던예가 7 예, 주변근육에도 296 www.hipandpelvis.or.kr

Soo-Sung Park et al.: MRI in Suspected Acute Septic Arthritis of the Hip Joint in Children A B C Fig. 1. 9-year-old boy with acute septic arthritis in Rt hip joint. (A) Coronal T1-weighted spin-echo MR image Siemens (IR/TE,450/11), (B) T2-weighted spin-echo MR image (3000/99), (C) fat-suppressed gadolinium-enhanced T1-weighed spinecho MR image (735/14), demonstrate effusion in Rt hip joint and diffuse enhancement in Rt hip joint synovium. A B C Fig. 2. 6-month-old girl with abscess in adductor muscle. (A) Coronal T1-weighted spin-echo MR image (TR/TE, 420/12), (B) T2- weighted spin-echo MR image (3000/99), (C) fat-suppressed gadolinium-enhanced T1-weighted spin-echo MR image (616/12), demonstrate abscess pocket in adductor muscle and myositis involving adductor muscle and obturator muscle. A B C Fig. 3. 22-day-old girl with abscess in psoas muscle. (A) Low signal intensity mass-like lesion is seen in Coronal T1-weighted spin-echo MR image (TR/TE, 450/11), (B) T2-weighted spin-echo MR image (3000/99) shows high signal intensity fliud signal in the mass-like lesion, (C) that lesion have inhomogeneous enhancement in fat-suppressed gadolinium-enhanced T1- weighted spin-echo MR image (735/14). www.hipandpelvis.or.kr 297

Table 1. Diagnostic Data in Twenty Patients with Suspected Septic Hip Arthritis No. Age / Sex PPh.* ESR CRP Result of Joint fluid MRI Findings WBC (mm/h) (mg/dl) culture WBC(/uL) Joint BM Capital Synovial Other Findings ( 10 9 /L) & diff. Effusion Signal Epiphysis Enhancement Alteration Signal Alteration 01 4 y+1 m/m 12.1 36 08.5 S. aureus 02 4 m/m 09.9 24 00.2 S. viridan Insufficient fluid Yes No No Yes 20,700/77% Yes No No Yes 03 10 m/f 10.5 22 1 S. aureus 200,000/85% Yes No Yes Yes 04 5 y+8 m/m 11.1 1070 02.1 S. aureus Uncooperative Yes Yes No Yes 05 7 y+2 m/f 11.1 1300 14.8 Negative 26,100/88% Yes No No Yes 06 1 m+6 D/M 10.6 20 1 P.aerugin** Uncooperative Yes Yes No Yes 07 9 y+8 m/m 12.7 19 00.6 Negative 6580/63% Yes Yes No Yes Ramus Osteomyelitis 08 14 y+1 m/f 11.7 97 16.3 S. aureus Not Performed No No No No Abscess in Iliacus M. 09 2 m+13 D/M 08.4 12.9 S. aureus Insufficient fluid Yes Yes Yes Yes 10 1 m+6 D/F 16.6 04.6 Ent.cloaca Uncooperative Yes No No Yes 11 6 y+10 m/m 14 71 10.9 Negative 60,800/92% Yes No No Yes 12 6 m+2 D/M 10.6 009.51 Strept pn 340,000/99% Yes Yes No Yes Muscle Signal Alteration 13 22 D/F 10.8 003.07 S. aureus Not Performed No No No No Abscess in Psoas M. 14 6 m+4 D/F 09.8 1070 11 Strept pn Not Performed No No No No Abscess in Adductor M. 15 15 D/M 15.6 009.13 S. aureus Not Performed Yes No No Yes Abscess in Soft Tissue 16 10 D/F 12.9 16.1 S. aureus Insufficient Fluid Yes Yes Yes Yes Muscle Signal Alteration 17 8 y+10 m/m 08.7 69 007.19 S. aureus 57,400/89% Yes No No Yes 18 29 D/F 13 002.34 Negative Insufficient Fluid Yes No No Yes Muscle Signal Alteration 19 5 y+6 m/f 11.7 13.6 Negative Uncooperative Yes Yes Yes Yes 20 11 m/m 17.3 89 004.17 S. aureus 72,530/94% Yes No No Yes * PPh.: peripheral WBC: white blood cell diff.: differential count BM: bone marrow S.aureus: Staphylococcus aureus S.viridan: Streptococci viridian ** P.aerugin: Pseudomonas aeruginosa Ent.cloaca: Enterobacter cloaca Strept pn: Streptococcus pneumoniae 298 www.hipandpelvis.or.kr

Soo-Sung Park et al.: MRI in Suspected Acute Septic Arthritis of the Hip Joint in Children 신호강도변화가같이있었던예가 3 예였고, 주변연부조직의농양형성이같이있었던경우도 1 예가있었다 (Table 1). 3. 원인균주와술후임상결과 20 예중 15 예 (75%) 에서술전관절천자시나수술중채취한검체에서균배양검사상균이검출되었으며 staphylococcus aureus 가 10 예 (50%) 로가장많았고, streptococcus pneumoniae 가 2 예, enterococcus cloacae, streptococcus viridans, pseudomonas aeruginosa 등이각각 1 예씩이었다. 수술후다음날부터통증감소, 발열소실등임상증상의호전을보였으며, 혈액검사상수술후평균 12 일 ( 범위 : 4-27 일 ) 에적혈구침강속도 (ESR) 과 C 반응단백 (CRP) 등염증성지표들이정상으로돌아왔다. 평균 2 년 2 개월추시관찰후재발된예는없었고 18 예에서정상적인관절운동범위를보였으며해당관절부위의단순방사선소견상특이한이상소견이없는양호한결과를보였으나, 골수염이동반되었던 2 예에선경도의관절운동제한및단순방사선소견상관절염후유증의소견이관찰되었으며 (Fig. 4), 이중 1 예는수술적치료 7 년경과후우측하지의 2 cm 단축소견이보여우측대퇴골의외반절골술을시행하였다. 고 찰 유, 소아기에발생하는화농성고관절염은치료를일찍 시행하지않으면관절연골등의파괴속도가빨라관절의완전한파괴, 여러형태의변형및관절운동제한을유발할수있기때문에조기진단이중요하다. 이를위해이학적검사, 혈액검사, 관절천자술, 방사선검사등을시행한다. 저자들은우선이러한관절주위연부조직의염증소견이의심되는 4 예를제외한 16 예에서관절천자검사를시행하였다. 그중 8 예에서관절천자검사가실패하였으며그원인을자기공명영상소견과종합하여분석한결과 4 예는천자된관절액의양이부족하여성분분석을시행치못했으며 2 예는장근과요근의근육내농양으로관절내삼출액이없었던경우였고 2 예는환자의비협조로제대로관절천자가이루어지지않았음을알수있었다. 급성화농성고관절염이의심되는경우단순방사선검사가민감한검사법은아니나골절이나 Legg-Calve-Perthes 병등을우선감별진단할수있고화농성관절염의경우에동반될수있는골수염소견이나관절삼출액으로인한주변연부조직종창이나관절아탈구등의간접소견을보일수있다. 본연구에서는단순방사선소견상이상소견을보인예는없어화농성고관절염의진단법으로써의단순방사선촬영소견이한계가있음을알수있었다. 초음파검사로도관절내의삼출액유무를알수있어관절액천자검사에유용하여 6) 본연구에서도관절천자검사시이를이용하였으나초음파검사로는동반된골조직의염증이나주변연부조직으로의감염이환여부를알기어려운단점이있다. 전산화단층촬영 (CT) 도관절내의삼출액이나주변근육 A B Fig. 4. (A) There was a residual deformity of right proximal femur and right acetabulum due to sequelae of septic arthritis in both hip antero-posterior, (B) frogleg lateral radiogragh. www.hipandpelvis.or.kr 299

의농양형성유무를파악하는데유용할수있으나 7) 소아에서방사선조사량이많은단점이있고골수내의염증성병변에대해알기어려운단점이있다. 또한자기공명검사에서활액막염증및삼출액소견은초기에쉽게나타날수있는소견이고민감하기때문에화농성고관절염의진단에도유용하게사용할수있다. Mazur 등 8) 은뼈스캔등의검사에비하여자기공명영상검사가위양성, 위음성의가능성이적어자기공명영상을먼저시행하고조직학적혹은미생물학적확진을시행할것을권장하였으며, Kwack 등 9) 과 Kim 등 10) 은자기공명영상의대퇴골두에서나타나는최대조영강도시점의시간차, 대퇴골골단에서의조영관류감소소견의차이를통해화농성고관절염과일과성활액막염의감별진단을용이하게할수있다고하였다. 하지만 Graif 등 11) 은이러한자기공명영상소견이화농성고관절염에특징적인것은아니기때문에병력, 혈액검사, 관절천자검사등이진단에필요하다고하였다. Learch 와 Farooki 12) 도비감염성염증성고관절병증에서도비슷한소견이나타날수있다고하면서절대적인진단척도로사용해서는안된다고하였다. 그외자기공명영상은비용상의문제, 금속삽입물의간섭현상, 석회화된골구조나피질골의낮은해상도에있어서는단점으로지적되기도한다 13). 그러나자기공명영상은고관절주위근육, 특히장요근주위나내전근주위의감염의진단에유용하다. 고관절주위근육의감염은고관절의화농성관절염과구분하기힘들어오진을하거나진단이늦어지는경우가있는데 14-16), 본연구에서는이와같이관절주위의근육에농양이형성되어급성화농성고관절염과감별이어려웠던 3 예에서자기공명영상을통하여근육내농양을발견하고파급정도를알아내어불필요한시험적관절절개술을피할수있었고만족할만한결과를 3 예모두에서얻을수있었다. 하지만본연구는여러면에서제한점이있다. 임상에서의시간적, 경제적인이유로다른진단도구가될수있는뼈스캔, 초음파, 전산화단층촬영등을모든경우에시행하지는못하여자기공명영상과의완전한비교분석이불가능하였다. 또한 3 차병원의특성상타병원을경유하여항생제등을사용하고내원하는경우의예들은증상이발현이더욱비특이적이여서조기에자기공명영상등을시행하지못한경우들도있었으며, 기술적인이유로관절천자검사를전례에서시행하지못하였다. 이에대해서보다많은증례를대상으로적극적인전향적연구가더필요할것으로사료된다. 결 론 소아의급성화농성고관절염의조기진단에자기공명영상이매우유용한방법으로사료된다. 특히주변연부조직 이나골조직으로확산된감염병소의범위에대한유용한정보를제공하여수술도달법및방법을결정할수있게하며, 또한고관절의화농성관절염과증상및이학적검사에서유사한소견을보이는주위연조직의감염, 농양등을정확히감별하여적절한치료가가능할수있게하는매우유용한검사법으로판단된다. REFERENCES 01. Betz RR, Cooperman DR, Wopperer JM, et al. Late sequelae of septic arthritis of the hip in infancy and childhood. J Pediatr Orthop. 1990;10:365-72. 02.Kang SN, Sanghera T, Mangwani J, Paterson JM, Ramachandran M. The management of septic arthritis in children: systematic review of the English language literature. J Bone joint Surg Br. 2009;91:1127-33. 03. Shaw BA, Kasser JR. Acute septic arthritis in infancy and childhood. Clin Orthop Relat Res. 1990;(257):212-25. 04.Cooper C, Cawley MI. Bacterial arthritis in an English health district: a 10 year review. Ann Rheum Dis. 1986;45: 458-63. 05. Sultan J, Hughes PJ. Septic arthritis or transient synovitis of the hip in children: the value of clinical prediction algorithms. J Bone Joint Surg Br. 2010;92:1289-93. 06.Zawin JK, Hoffer FA, Rand FF, Teele RL. Joint effusion in children with an irritable hip: US diagnosis and aspiration. Radiology. 1993;187:459-63. 07.Lopez M, Sauerbrei E. Septic arthritis of the hip joint: sonographic and CT findings. J Can Assoc Radiol. 1985; 36:322-4. 08.Mazur JM, Ross G, Cummings J, Hahn GA Jr, McCluskey WP. Usefulness of magnetic resonance imaging for the diagnosis of acute musculoskeletal infections in children. J Pediatr Orthop. 1995;15:144-7. 09. Kwack KS, Cho JH, Lee JH, Oh KK, Kim SY. Septic arthritis versus transient synovitis of the hip: gadolinium-enhanced MRI finding of decreased perfusion at the femoral epiphysis. AJR Am J Roentgenol. 2007;189:437-45. 10. Kim EY, Kwack KS, Cho JH, Lee DH, Yoon SH. Usefulness of dynamic contrast-enhanced MRI in differentiation between septic arthritis and transient synovitis in the hip joint. AJR Am J Roentgenol. 2012;198:428-33. 11.Graif M, Schweitzer ME, Deely D, Matteucci T. The septic versus nonspecific inflamed joint: MRI characteristics. Skeletal Radiol. 1999;28:616-20. 12.Learch TJ, Farooki S. Magnetic resonance imaging of septic arthritis. Clin Imaging. 2000;24:236-42. 13. Modic MT, Pflanze W, Feiglin DH, Belhobek G. Magnetic resonance imaging of musculoskeletal infections. Radiol Clin North Am. 1986;24:247-58. 14.De Boeck H, Noppen L, Desprechins B. Pyomyositis of the adductor muscles mimicking an infection of the hip. Diagnosis by magnetic resonance imaging: a case report. J Bone Joint Surg Am. 1994;76:747-50. 15.Firor HV. Acute psoas abscess in children. Clin Pediatr (Phila). 1972;11:228-31. 16.Thomas S, Tytherleigh-Strong G, Dodds R. Adductor 300 www.hipandpelvis.or.kr

Soo-Sung Park et al.: MRI in Suspected Acute Septic Arthritis of the Hip Joint in Children myositis as a cause of childhood hip pain. J Pediatr Orthop B. 2002;11:117-20. 국문초록 소아급성화농성고관절염의증환자에서자기공명영상의유용성 박수성 이수호 심경보울산대학교의과대학서울아산병원정형외과학교실 목적 : 소아에있어급성화농성고관절염이의심되는경우에정확한진단과그에따른치료방법을결정하는데있어서자기공명영상의유용성과임상결과를평가하고자하였다. 대상및방법 : 2003 년 3 월부터 2007 년 5 월까지급성화농성고관절염이의심되어자기공명영상검사를시행한환아 20 명을대상으로하였으며평균연령은 3 년 5 개월 (10 일 -14 세 ) 이었으며평균추시기간은 2 년 2 개월 (1 년 -3 년 6 개월 ) 이었다. 이들환아에서시행한자기공명영상소견및임상적결과를후향적으로분석하였다. 결과 : 자기공명영상소견상관절삼출액이증가가있었던예가 17 예 (85%) 였으며, 그중골단이나골간단부의신호강도변화가있었던예가 7 예, 주변근육의신호강도변화가같이있었던예가 3 예, 연부조직의농양형성이있었던경우가 1 예있었다. 관절삼출액증가없이관절주변근육내농양으로급성화농성고관절염과유사한임상증상을일으킨예가 3 예 (15%) 있었다. 추시결과후유증으로인한골변형을보인 2 예를제외한 18 예에서진단에유용한정보를제공하였다. 결론 : 자기공명영상은급성화농성고관절염의감별진단뿐아니라주변연부조직이나골조직으로확산된감염병소에대한유용한정보를제공해줄수있는유용한검사법이라사료된다. 색인단어 : 소아, 화농성고관절염, 자기공명영상 www.hipandpelvis.or.kr 301