Clinical Ultrasound REVIEW Clinical Ultrasound 2016;1: 충수염의초음파진단 김대현이앤김연합내과 Ultrasonography of Appendic

Clinical Ultrasound REVIEW Clinical Ultrasound 2016;1:19-38 충수염의초음파진단 김대현이앤김연합내과 Ultrasonography of ppendicitis Dae Hyun Kim Lee & Kim Union Internal Medicine Clinic, Daegu, Korea ppendicitis is common cause for acute abdomen. With widespread use of high resolution ultrasonography, it has been widely used to evaluate patients with acute right lower quadrant pain. Ultrasonography is easy to perform, minimally invasive, lacks ionizing radiation, allows dynamic visualization of the abdominal organs and is of lower cost compared with computed tomography. This examination can visualize hypertrophy and disruption of the layered structure of the appendiceal wall, accumulation of purulent fluid, and the presence of a fecalith in the appendix. Significance of ultrasonography in the diagnosis of appendicitis is as follows: firstly, it can help definitely diagnose appendicitis in patients with suspected appendicitis or atypical clinical presentation. Secondly, it can help rule out appendicitis in patients with lower abdominal pain by demonstrating normal appendix. ut ultrasonography has some limitations in patients with atypical position of appendix or obesity. So understanding of various ultrasonographic findings of appendicitis and acquisition of ultrasonographic techniques such as position change and graded compression can help reduce false positive and false negative diagnosis of appendicitis. Keywords: Ultrasonography; ppendix; ppendicitis 서론 급성충수염은수술이필요한급성복증의가장흔한원인질환이다 [1]. 평생동안충수염으로수술할확률은약 7% 정도로알려져있으며 [2] 10세에서 19세사이의나이, 남자, 백인에서더흔하다 [3]. 급성복통환자에서초음파검사는소화관의가스나뼈에의해서음향창이좋지않고복부비만환자에서검사가어렵고, 검사자의숙련도에따른진단율의차이가있을수있는단점이있으나, 비침습적이고, 간편하고, 환자와대화하면서압통부위를실시간으로검사할수있고, 소화관의연동운동과혈류분포의확인이가능하고, 충수의벽구조를알수있고, 반복 적인검사가가능하며특히방사선조사의위험이없어소아와임산부에게안전하게사용할수있는장점이있어서 1차검사로서많이이용된다. 충수염진단에있어서초음파검사의의의는급성충수염이의심되거나비특이적임상소견이있는환자에서충수염진단을확정하고, 충수주위염증의정도를파악할수있고, 비전형적인충수의위치를찾아낼수있으며하복부통증환자에서정상충수를찾음으로써충수염진단을배제하는것이다 [4-6]. 충수염의초음파진단은전형적인경우비교적쉬우나비전형적인위치에있거나비만환자에서는위음성이증가하므로다양한형태의충수염소견을숙지하고자세변경과단계적압박과같은소화관초음파의기본수기를습득하는것이무 ddress for Correspondence: Dae Hyun Kim, M.D., PhD. Lee & Kim Union Internal Medicine Clinic, 2 Yulhadong-ro 23-gil, Dong-gu, Daegu 41119, Korea Tel: +82-53-964-3370, Fax: +82-53-964-3372 E-mail: pylori@empas.com Received : 2016. 3. 14 Revised : 2016. 3. 25 ccepted : 2016. 3. 29 Copyright 2016 The Korean ssociation of Clinical Ultrasound This is an Open ccess article distributed under the terms of the Creative Commons ttribution 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. pissn 2465-7786 eissn 2465-7794

Clinical Ultrasound Vol. 1, No. 1, May 2016 엇보다중요하다. 본고에서는충수염의병태생리, 충수의초음파스캔법그리고충수염의다양한초음파소견에대해서기술하고자한다. 본론충수염의병태생리 충수염은충수의내강이막힘으로써일련의경과를거치게된다. 내강이막히는원인은분변이가장흔하고, 림프조직의증식, 이전바륨검사로인한찌꺼기, 채소, 과일씨, 또는기생충도원인이된다 [7]. 충수내강이막히면닫힌창자폐쇄 (closed loop obstruction) 가발생하게되고충수내강으로점액의분비는지속되어충수내강의확장을일으켜서충수내강압이지속적으로증가하게된다. 이때내장구심신경 (visceral afferent nerve) 의신경말단을자극함으로써배꼽주변의모호하고경미한둔통을 일으킨다 [8]. 이러한내강확장은충수의연동운동을증가시킴으로써내장통외에경련통을유발하기도한다. 지속적인내압상승은충수벽의정맥울체를초래하여점막방어가손상되면서세균의침입을초래하고염증을일으키는화농성충수염단계가된다. 더진행되어동맥공급장애로조직허혈을초래되면충수의벽전체에괴사와장막의삼출물이일어나게되는괴저성충수염단계가된다 [9]. 충수의초음파스캔법충수의초음파검사를하기위해서먼저볼록형저주파탐촉자 (3-5MHz) 를사용하여전체적인윤곽을확인하는데우상복부에서우측신장의장축영상을얻은후하방으로이동하여상행결장의종단상을찾고우하복부까지이동하면우측요근과만나게되는맹장에도달한다. 여기에서탐촉자를횡단면으로회전하면좌측에맹장, 하방에우측요근, 상방에말단회장, 우 C D E F Figure 1. () Longitudinal view of ascending colon using high frequency linear probe shows haustration (H) between the air-filled loops (arrows). () Longitudinal view of cecum (C) shows semisolid feces filled cecal tip which ends at psoas muscle (P). (C) Transverse view of right iliac fossa. Note heterogenous echogenicity within the cecum (C) which is connected to cecoappendiceal junction (arrows). lso noted appendix () lying between terminal ileum (TI) and psoas muscle (P). (D) Longitudinal view of ileocecal valve (arrows) connecting terminal ileum and cecum. Normal appendix. (E) Longitudinal section of normal appendix. Note the appendix (arrows) draping over the iliac vessels and the well-preserved submucosal layer (arrowhead) and acoustic reflection from the collapsed luminal interface (thick arrow). (F) Transverse section of normal appendix shows ovoid shaped appendix (arrows) with normal caliber (3 mm, calipers not shown). H, haustration; C, cecum; TI, terminal ileum;, appendix; P, psoas muscle; I, iliac artery. 20

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 측에장골동맥을관찰할수있다 [10]. 다음으로고주파선형탐촉자 (7-12MHz) 로바꾼후점진적압박 (graded compression) 을통하여말단회장내가스를밀어내고탐촉자와우측요근사이의거리를좁히면서우측요근과말단회장사이로주행하는충수를발견할수있다 [10,11]. 간혹장회전이상이나내장역위환자에서는충수위치가좌하복부, 우상복부또는배꼽주변등다양한부위에위치할수있으므로맹장을먼저찾은후충수를 찾거나증상이있는환자의경우최대압통부위를스캔하는것이중요하다 (Fig. 1). 충수는말단부의위치에따라서 2시방향으로향하는회장전방형 (preileal), 3시방향으로향하는회장후방형 (postileal), 4-5시방향으로향하는골반형 (pelvic), 6-7시방향으로향하는맹장하방형 (subcecal), 10-12시방향으로향하는맹장후방형 (retrocecal) 등으로구분한다 (Fig. 2) [12]. 우리나라의경우골반형과회장후방형이가장흔한위치로알려져있어앙와위상태에서우하복부에서말단회장의후방과우측요근의앞쪽의이부위에서먼저충수를찾아야충수발견율을높일수있다. 이위치에서충수가발견되지않는다면충수의위치는맹장후방형일가능성이높으므로후방압박이나, 좌측와위로자세변경후관찰하면된다. 저자가 203명의정상인을대상으로시행한연구에의하면충수의위치는골반형이 55%, 맹장하방형이 20%, 회장후방형이 16%, 맹장후방형이 9% 여서가장흔한골반부위를먼저스캔하는것이충수발견율을높일수있었다. 충수염의초음파소견 충수의최대전후직경의증가 (increased maximal outer diameter, Fig. 3) Figure 2. Diagram of position of appendix. T, tenia coli; C, cecum; TI, terminal ileum. 충수의전후직경의계측은횡단상에서측정하며충수전벽 의장막층에서후벽의장막층까지의거리로정의한다. 정상은 Figure 3. Increased maximal outer diameter of appendix: Transverse section () and longitudinal section () of appendix showed maximal outer diameter of 11.5 mm (calipers). 21

Clinical Ultrasound Vol. 1, No. 1, May 2016 6 mm 이내이고충수염이발생하면중간정도의압박상태에 서최대전후직경이 7 mm 이상이다 [13-15]. 충수염진단시 6 mm 를기준점 (cutoff value) 으로하면진단의민감도 100%, 특이 도 68% 였고, 7 mm 를기준점으로할경우민감도 94%, 특이도 88% 로알려져있다 [16]. 최대전후직경이 6 mm 에서 7 mm 사이 에속하는경우에는색도플러검사에서의혈류증가시충수염에 부합하는소견으로볼수있다. 충수의최대벽두께의증가 (increased maximal mural thickness, Fig. 4) 충수의전벽또는후벽에점막층에서장막층까지의거리로정 의하고정상에서는 2 mm 이내이다 [17]. 충수벽두께가 3 mm 이 상으로증가되는것이충수염의중요한소견이다 [1]. 화농성충 수염상태가되면고에코의점막하층이염증성부종으로인하 여두꺼워지고저에코의근육층까지염증이파급되어두꺼워진 다. 충수의기시부에서말단부위까지비후된점막하층의구조 가유지되는것이화농성충수염의특징이다 [18]. 점막하층의소실 (focal or global loss of submucosal layer, Fig. 5) 염증반응이점막하층까지진행되어점막하층의궤양과괴사 가오게되면고에코의점막하층의구조가부분적으로나전체 적으로소실이오는데천공성충수염에서더높은빈도로관찰 이된다 [19]. 탐촉자로압박시압박되지않는다 (noncompressibility, Fig. 6) 충수염이발생하면충수벽의비후와충수주변의지방침착으 로인하여압박시에도직경의변화가없는것이특징이다 [14]. 색도플러검사상혈류의증가 (increased vascularity on color doppler, Fig. 7) 색도플러검사에서충수벽과충수주변의지방조직으로혈류 증가소견을관찰할수있다. 하지만괴저성충수염상태가되면 충수벽의혈류는감소되거나거의관찰이되지않으나충수주 변지방조직으로는혈류증가를관찰할수있다 [20,21]. 충수분석 (appendicolith, Fig. 8) Figure 4. Longitudinal section of appendix demonstrated maximal mural thickness of 4.4 mm (calipers)., appendix. 급성충수염의약 30% 에서충수분석을관찰할수있고초음파에서는후방음영을동반한고에코성병변으로관찰되고크기, 모양및개수가다양하다 [22-25]. 충수분석은충수내강의가스및분변과감별이필요한데가스음영도고에코이나불균질하고지저분한후방음영을보이고탐촉자로압박시모양이변하는특징이있고분변의경우상대적으로에코가높지않고후방음영을동반하지않는다 [26]. 화농성, 괴저성, 천공성충수염으로갈수록충수분석의빈도가높아지게된다. 만약충수분석의위치가말단부에위치하게되면분석의원위부에만충수염이발 Figure 5. () Transverse section of appendix () demonstrated circumferential loss of submucosal layer (arrow). () Longitudinal section of appendix () showed partial loss of submucosal layer (arrows)., appendix. 22

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 생할수있다. 천공성충수염에서는충수주변의농양, 액체저 류부위에충수분석을관찰할수도있다 [27]. 충수분석이있으면 충수염의위험성이증가하게되지만정상인에서도 13% 에서충 수분석이발견되고무증상충수분석만으로는충수염의진단에 불충분한소견이며충수벽두께의증가나충수주변의염증성 소견과동반될때의미가있다고한다 [28]. 충수주변의고에코성지방조직 (periappendiceal fat infiltration, Fig. 9) 충수염이발생하게되면처음에충수간막 (mesoappendix) 에 있는지방에염증이생기게되고, 점차적으로맹장주변, 장간 막, 대망의지방조직까지확산되어초음파에서고에코성충수주위지방조직으로관찰되고색도플러검사에서혈류증가를볼수있는데충수주위의고에코구조물 (periappendiceal hyperechoic structure), 증가된맹장주위고에코병변, 저명한충수주위의고에코병변등다양한이름으로기술된다 [20,29]. 양상은충수의한면에국한되기도하고, 충수주위전체를둘러싸는형태또는충수주위와주변장기주변까지걸쳐있는형태로구분되며충수염의심한정도에비례해서그범위도증가하고 [30] 비천공성충수염의 13-54%, 천공성충수염의 31-64% 의빈도로관찰된다 [30]. 복통환자의초음파검사에서고에코성지방병변이관찰되 Figure 6. Dual gray scale compression transverse section of appendix. () efore compression, () during compression showing uncompressible distended appendix ()., appendix. Figure 7. Transverse section of appendix in acute appendicitis with hyperemia of appendiceal wall (long arrow) and mesoappendix (short arrow)., appendix. Figure 8. Transverse section of appendix showing echogenic appendicolith (arrow) within the lumen of the appendix casting posterior shadowing (arrowheads). 23

Clinical Ultrasound Vol. 1, No. 1, May 2016 는경우반드시그주위에충수염을포함하여크론병, 세균성 장염, 허혈성장염등의유무를확인하여야한다. 충수주위농양소견 (periappendiceal abscess, Fig. 10) 천공성충수염이발생하게되면충수주위에액체저류와농양 이관찰된다 [20,21]. 장간막림프절비대및맹장벽의비후 (mesenteric lymph node enlargement, cecal wall thickening, Fig. 11) 급성충수염이발생하면반응성으로주변장간막림프절비대 가관찰되고, 이림프절은난원형이고, 에코는등에코또는주 변근육에비해서저에코로보인다. 또한충수의염증이충수간 막, 맹장주위로파급되어서국소적인맹장벽비후를초래한다 [20,21]. 특히소아에서는충수염외에도급성회맹장염, 장간막 림프절염에의해서도장간막림프절비후및맹장벽비후가동 반될수있어서진단에보조적인소견으로볼수있겠고, 충수 자체의염증소견의유무가충수염진단에결정적인역할을한 다 [20,21]. 병리학적으로분류한급성충수염 급성카타르성충수염 (acute catarrhal appendicitis, Fig. 12) 여러가지원인에의한충수입구의폐쇄로충수내강의점액 의저류가오고내강의압력이증가되어림프흐름의장애가초 래되고점막면의미란으로세균감염이유발되면서충수벽의점 막층의충혈과부종, 백혈구침윤등이발생하는상태가되지만 점막하층과근육층은백혈구의침윤이없는상태를말하는것 으로서초기충수염이라고도한다 [31-34]. 하지만무증상충수 절제표본의약 1/3 에서이러한소견이관찰된다는보고가있어 [35] 대부분의연구자들은근육층에백혈구침윤이동반된경 Figure 9. Transverse section of appendix showing round distended appendix () with increased periappendiceal echogenicity representing fatty infiltration (F)., appendix; F, periappendiceal fat infiltration. Figure 10. Transverse section of appendix () showing disruption of serosal layer with periappendiceal fluid collection (arrows). F, periappendiceal fat infiltration;, appendix. Figure 11. () Transverse scan of right iliac fossa showed mesenteric lymph node enlargement (arrow). () Transverse scan of right iliac fossa demonstrating focal cecal wall thickening (arrow). C, cecum. 24

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 우를급성충수염진단의근거로설명한다 [35]. 초음파검사에서 는충수의직경은 5-6 mm 정도가경도이고충수벽의층구조 는유지되며점막층의부종이있으나점막하층의비후는동반 되지않는다 [36]. 색도플러검사에서충수벽의혈류증가가있거 나충수벽이나충수주위에고에코의지방조직이증가되어있다 면진단에도움을준다. 초기충수염의경우원인이소실된다면 저절로호전되기도하지만일부에서는회복되지않고더진행이 되거나증상이반복되면서만성충수염의원인이되기도한다 [35,36]. 급성화농성충수염 (acute suppurative appendicitis, Fig. 13) 충수의내강의폐쇄가지속되면점막층의부종과충혈이더 욱심해지면서정맥순환의장애가초래되고세균감염이진행되 어호중구가점막층과근육층에현저히침윤이되고충수벽의 전층이화농성삼출물로차고장막층밖으로삼출물이두껍게 덮이게되는데이시기를급성화농성충수염이라고한다. 급성 화농성충수염의초음파소견은불명확한층구조, 중증도로 늘어난충수직경, 제 2 층점막고유층의소실또는두께의감소, 고에코의점막하층두께의증가및도플러혈류검사에서충수벽 과충수주위의혈류증가등이다 [35,36]. 급성괴저성충수염 (acute gangrenous appendicitis, Fig. 14) 화농성충수염에서허혈성변화가심해져서동맥혈류의폐쇄 가초래되어상대적으로취약한충수간막의반대편충수벽전 층의괴저성궤사가온경우를말하며, 초음파소견은고에코 점막하층의국소적내지전층의단락, 농양을시사하는국소적 인액체저류및도플러혈류검사에서충수벽혈류의감소내지 소실이특징이다 [35,36]. Figure 12. Catarrhal appendicitis in a 22-year old male. () Transverse section of appendix demonstrated ovoid configuration () mild hyperemia on color doppler study (arrow). () Longitudinal section showed mildly distended tubular structure with intraluminal exudates and feces (). Note no thickening of submucosal layer (short arrow). He complained right lower quadrant pain for 2 days. His WC count was 15,300 per mm 3. He underwent appendectomy which revealed early acute appendicitis., appendix; P, psoas muscle; WC, white blood cell. Figure 13. Suppurative appendicitis in a 35-year old male. () Longitudinal section of appendix () showed distended tubular structure with thickening of echogenic submucosal layer (arrow). () Transverse section of appendix demonstrated noncompressible round inflamed appendix () with periappendiceal fatty change., appendix. 25

Clinical Ultrasound Vol. 1, No. 1, May 2016 다양한형태의충수염노인의충수염 (appendicitis in elderly, Figs. 15 and 16) 최근노년인구의증가로인하여 60세이상환자의충수염은늘고있는추세이며전체충수염의 8.3% 에서 16.4% 로보고하고있다 [37-40]. 전체충수염은여자에비해서남자가빈도가높으나노년에서는여자의평균수명이길어 1:1.1-1:1.67 로여성에서빈도가높다고알려져있다 [37-41]. 비노인에서보다노인에서는임상양상이비특이적인경우가많고, 천공, 농양과같은합병증의빈도가증가하게되므로진단에주의를요한다 [42]. 노인의경우충수벽의림프조직의감소와섬유화로인한협착으로충 수내강의용적이감소하므로 (Fig. 15) 충수의폐쇄시압력증가가조기에발생함으로써충수염의진행이빠르고혈관의경화에의해허혈상태가쉽게초래되며 [43], 장간막염증차단기능의약화, 대망의기능저하, 영양부족등으로인하여천공등과같은합병증의빈도가증가하게된다 (Fig. 16). 또한충수의연동운동이감소되어충수내로역류된분변과찌꺼기의배출이원활하게되지않는다 [44]. 반면에면역기능감소로인한발열과백혈구증가가경미하고복부근육위축으로반발압통이적으며노화에의한신경계의반응변화로통증에대한인지감소로인하여임상양상이비전형적이어서진단에주의를요한다 [43,45-48]. C Figure 14. Gangrenous appendicitis in a 27-year old female. () Transverse section demonstrated round distended appendix () with focal loss of submucosal layer (arrowhead) indicating focal gangrenous change within appendix. Note that anterior aspect of submucosal layer is intact (arrow), indicating no circumferential gangrene of appendix. () Longitudinal section of appendix showed tubular distended appendix with loss of echogenic submucosal layer of posterior wall (arrowheads) Note well preserved echogenic submucosal layer of anterior wall (arrows). (C) Color doppler image of longitudinal section of the appendix () demonstrating absence of vascularity indicating gangrenous change., appendix. Figure 15. 58-year old male with atrophied appendix. () Transverse section of appendix. Note oval shaped appendix with maximal outer diameter of 2 mm and narrow lumen (arrows) between psoas muscle and terminal ileum. () Longitudinal section of appendix demonstrating marked obliteration of lumen throughout the entire length (arrows). C, cecum; TI, terminal ileum; P, psoas muscle. 26

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound C D Figure 16. 75-year old female with perforated appendicitis. () Transverse view of appendiceal base (arrow, 6 mm in diameter). Note markedly increased echogenicity within the inflamed periappendiceal fat (F). () Note anechoic fluid collection indicating abscess () inferior to the cecum. (C) Transverse section of appendix (). Note markedly increased echogenicity of periappendiceal fat (F) surrounding inflamed appendix which showed indistinct wall layers. (D) Transverse view of right iliac fossa showed anechoic fluid collection indicating periappendiceal abscess () inferior to the cecum. lso noted increased echogenicity within periappendiceal inflamed fat (F). C, cecum; F, periappendiceal inflamed fat;, appendix. C Figure 17. 15-year old child with ileocecitis. () Long axis image of ileocecal valve (arrows) showed marked wall thickening. Note prominent echogenic submucosal layer (SM). () Longitudinal section of appendix (arrows) demonstrated gut-pattern tubular structure, with 2.5 mm wall thickness and 5.2 mm lumen width anterior to iliac vessels on gray-scale ultrasonogram. Note prominent hypoechoic deep mucosal layer which corresponds to lymphoid hyperplasia. (C) Transverse section of appendix showed ovoid configuration with 3 mm lumen width anterior to iliac artery (I). C, cecum; SM, submucosal layer; TI, terminal ileum; P, psoas muscle; I, iliac artery. 27

Clinical Ultrasound Vol. 1, No. 1, May 2016 소아의충수염 (appendicitis in children, Figs. 17 and 18) 충수염은어느연령에서나발생할수있지만대개 10-20 대사이에빈발하고 2세이하에서는비교적드문것으로알려져있다 [43,45,49,50]. 소아에서의급성복통은흔하게볼수있고수술적치료가필요없는비외과적인질환과충수염을감별하는것이중요한데초음파, 컴퓨터단층촬영 (computed tomography, CT) 그리고점수제 (alvarodo score, pediatric appendicitis score) 를적용하여진단의정확도를높이는시도를하고있지만여전히음성충수절제술의빈도가 10-30% 로높은편이다 [37,51]. 소아의우하복부통증시에급성회맹장염과의감별이중요한데, 이경우회맹장부위의비후와정상충수를관찰함으로써진단 할수있다 (Fig. 17). 특히성인에비해서소아에서는방사선조사의위험성이없고 CT에버금가는민감도와특이도를가진초음파검사의중요성이부각되고있다 [10]. 소아의충수염은초기증상이복통이외에오심구토, 열, 설사와같은비특이적인증상을많이호소하고, 병의진행이빠른특징이있으며특히미취학아동의경우의사표시능력이떨어져서초기진단이어렵고지연진단으로인한천공성충수염의빈도가성인에비해서높다. 또한충수벽의점막층에있는림프조직의발달로인하여바이러스감염시림프조직의증식으로충수의폐쇄가쉽게온다. 해부학적특성상충수벽의섬유조직이적고얇아서충수염의진행이빠른경우가많고복강내의염증을국소화하려는인체방어능력이저하되어있고 [52-55], 대망의발육이완전하지못하 Figure 18. 11-year old girl with acute appendicitis. Longitudinal section of the appendix showed normal proximal appendix (arrowheads) draping over the iliac vessel (IV) and distended tip of appendix (T). Note two hyperechoic appendicoliths (arrows) with posterior acoustic shadowing. C, cecum; P, psoas muscle; IV, iliac vessel; T, tip of appendix. Figure 19. 24-year old female with acute appendicitis (pregnancy 16 weeks). () Transverse section of appendix showed round distended appendix (calipers, 6.9 mm in diameter). () Longitudinal section of appendix showed tubular distended appendix (calipers) with thickened echogenic submucosal layer. 28

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 여서복막염의위험성이증가한다 [53,56]. 임신중의충수염 (appendicitis in pregnancy, Fig. 19) 급성충수염은임신중외과적인수술의가장흔한질환이며발생빈도는분만수 1,500명에서 1,700명당 1명에서발생하는것으로알려져있고특히임신 2기에서많이발생한다 [57,58]. 임신중에는자궁의크기에비례해서맹장의위치가평소위치에비해서상승하게되어임신 5개월이되면배꼽부위까지, 임신후반기에는우상복부나심와부에위치할수있다 [59]. 임신중급성충수염은조기양막파수, 조기진통그리고태아사망과같은합병증이동반될수있으므로조기진단이산모및태아의예후결정에중요하다 [59,60]. 환자가호소하는최대압통부위를검사하는것이중요하고환자를좌측와위로이동시킨후커진자궁을이동시켜충수를관찰하는것이도움이된다. 2차성충수염 (secondary appendicitis, Fig. 20) 2차성충수염은충수의염증이충수내강의폐쇄로인한것이아니고대장이나충수주위의병변으로인하여충수주위로 염증이파급되어생기는충수주위염 (periappendicitis, serositis) 을말하고, 이는교감신경성벽부종 (sympathetic mural edema) 에의한것으로알려져있다 [61]. 내인성과외인성 2차성충수염으로구분하며, 내인성은충수와연결된맹장과대장의염증에의한것이고 ( 예, 허혈성장염, 세균성장염, 위막성장염등 ) 외인성은담낭, 간, 방광, 난소, 신장또는말단회장등주변장기의병변 ( 크론병, 방광염, 담낭염, 에스결장게실염등 ) 이충수로파급되어염증을일으키는것이다 [61]. 맹장벽비후의양상에따라서 1차성충수염과구분하는데, 1차성충수염의경우맹장벽비후가국소적, 비전주성, 비대칭적, 불규칙한반면 2차성충수염의경우전주성, 대칭적, 규칙적인비후가특징이다 [62]. 그외에초음파검사에서충수의확장은두경우에모두있을수있으나, 충수벽의비후와충수주위지방침착은 1차성충수염의특징적인소견이다. 색도플러검사에서는 1차성충수염은비후된충수벽내부로혈류증가소견이있는반면에 2차성충수염은충수의장막외측에혈류증가소견을관찰할수있는것이특징적인소견이다 [63,64]. C D Figure 20. 28-year old female with ileocecitis with secondary appendicitis. () Diffuse cecal wall thickening(mainly hypoechoic mucosa [M] and hyperechoic submucosa [SM]). () Note wall thickening of terminal ileum (arrow). (C) Transverse section of appendix showed round distended appendix () with mild hyperemia at subserosal layer on color doppler study. (D) longitudinal section of appendix demonstrated mildly enlarged appendix (, 6.5mm in diameter, calipers not shown) without appendiceal wall thickening and periappendiceal fatty change. Note well preserverd wall stratification of the appendix (arrows). SM, submucosa; M, mucosa;, appendix. 29

Clinical Ultrasound Vol. 1, No. 1, May 2016 비만환자의충수염 (appendicitis in obese patient, Fig. 21) 비만환자에서는두꺼운복벽의지방층에의해서음향감쇠가 증가하고초음파빔의투과가감소됨으로써깊숙한위치에있는 충수의관찰이힘들다 [65]. 이경우초음파빔의깊은침투가가 능한저주파탐촉자로스캔하는것이중요하고하모닉기법을사 용하면더좋은영상을얻을수있다 [65]. 앙와위에서잘관찰되 지않는경우에는좌측와위로체위변경을하면도움이되고, 탐촉자로충분한압박을하여복벽과충수사이의거리를줄이 게되면더좋은영상을얻을수있다 [66,67]. 국소충수염 (focal appendicitis, distal appendicitis, Fig. 22) 충수전장의원위부 1/3 부위에국한된염증을국소충수염이 라고정의하고급성충수염환자의 5-20% 를차지한다. 이경우 근위부에는정상적인충수의모양을보이므로충수염진단의 위음성가능성이있어우하복부압통을호소하는환자에서는반드시맹관으로끝나는충수의말단부위까지확인하여야한다 [68-70]. 천공성충수염 (perforated appendicitis, Fig. 23) 급성천공성충수염은 19-36% 에서발생하는것으로보고하고있다 [71-74]. 급성천공성충수염과비천공성충수염의감별은중요한데, 천공성충수염인경우수술직후에합병증이발생할위험성이증가되기때문에응급으로수술을시행하지않고항생제투여같은보존적내과치료나저명한농양이있는경우경피적배액술로치료한후에간헐기충수절제술을시행할수있다 [75-77]. 급성천공성충수염환자에서수술전에천공성충수염을정확히진단하는것이야말로이질환의높은이환율과사망률 [78] 그리고수술방법이나수술시기에영향을줄수있기때문에중요하다 [79,80]. 고해상력초음파를이용한단계적 Figure 21. 26-year old obese male (body weight: 115 kg) with suppurative appendicitis. () In supine position, appendix was not visualized due to severe obesity. () fter changing into left lateral decubitus position, distended appendix (arrows) was well visualized. Figure 22. 23-year old man with tip appendicitis. Longitudinal section of the appendix showed normal proximal appendix (P, 4.1 mm in width) and distended inflamed tip of appendix(t, 10 mm in width), the last containing appendicolith (long arrow) with posterior acoustic shadowing and partial loss of submucosal layer of tip of appendix (short arrow). P, proximal appendix; IV, iliac vein; T, tip of appendix. 30

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound C D Figure 23. () 43-year old male with perforated appendicitis. Longitudinal section of distal appendix demonstrating disruption of serosal layer (long arrow) and periappendiceal abscess (short arrow). () 70-year old female with perforated appendicitis. Longitudinal section of distal appendix demonstrating loss of submucosa of posterior wall of appendix (arrows). (C) 70-year old female with perforated appendicitis. Transverse section of appendix demonstrating periappendiceal fluid collection (arrow). (D) 36-year old female with perforated appendicitis demonstrating normal appearing proximal appendix (arrow) with periappendiceal abscess ()., appendix. Figure 24. 67-year old male with retrocecal appendicitis. Oblique scan of right flank showed longitudinal section of appendix (app). Note the cecoappendiceal junction (short arrow) on the right side and appendiceal tip (long arrow) on the left side of the image which is reversed compared with postileal appendix. 31

Clinical Ultrasound Vol. 1, No. 1, May 2016 압박초음파는충수염을진단하는데있어서는유용한진단방법이라는것이과거의여러보고에서입증되었지만천공성충수염을진단하는데있어서는아직까지논란이적지않다 [81,82]. 최근고해상도초음파를이용한연구에서충수주위체액저류, 점막하층전층의소실, 장막층의파열, 비대칭적인충수벽비후, 10.5 mm 이상의최대단면직경등이천공성충수염을의심할수있는소견으로알려졌다 [30,83]. 종종충수주위농양내부에후방음영을동반하는고에코의충수분석이관찰되는경우도있다. 초음파검사시에저주파탐촉자를이용하여깊숙이위치하는충수주위농양이나체액저류를놓치지않는것이중요하다. 후맹장충수염 (retrocecal appendicitis, Fig. 24) 우하복부의우측요근과말단회장사이에서충수가관찰되지않을때는맹장후방에위치한충수의가능성을염두에두어야한다. 후맹장충수염은임상양상이우측옆구리나우상복부통증을호소하는경우가많고, 초음파검사에서앙와위에서 는적절한압박을하더라도관찰할수없는경우가있어서좌 측와위로체위변경을한후우측옆구리를음향창으로압박을 하면맹장내의가스를우회해서맹장후방의충수를관찰할수 있다 [67]. 자발적으로회복되는충수염 (spontaneously resolving appendicitis, Fig. 25) 경도의급성충수염환자에서항생제치료유무에상관없 이복통이발생한후 24 시간에서 48 시간이내에저절로호전되 는경우를말하며, 그원인은부드러운분석 (soft fecalith) 이충 수기시부에막혀있다가저절로빠져나가거나, 림프조직의증 식으로인한폐쇄가있다가저절로호전되는경우를일컫는다 [11,14,81,84-86]. 초음파소견은염증이있는충수가저명하게 관찰되며추적검사시점차충수의직경이감소되고결국정상 으로회복된다 [85]. 충수염으로수술받았던환자들중 7-25% 에 서는이전에비슷한증상을경험한병력이동반되는 [87-91] 것 C D E F Figure 25. 53-year old male with spontaneously resolving appendicitis. () Transverse section of appendix showed round distended with target sign (calipers, maximal outer diameter was 7.8 mm). () Longitudinal section of appendix (arrow) demonstrated distended appendix with mildly hyperechoic periappendiceal fatty change. (C) Transverse section of appendix showed hyperemia of appendiceal wall on color doppler study (arrow). Ultrasonographic findings were compatible with acute appendicitis, but symptoms of the patient was nearly improved and he denied right lower quadrant tenderness. So he was suspected of having spontaneously resolving appendicitis and antibiotic therapy was given. (D) On follow-up ultrasonography 3 days later, maximal outer diameter of appendix (calipers) was decreased to 4.8 mm. (E, F) On follow-up after 10 days, maximal outer diameter was further decreased to 4.1 mm (calipers) without recurrence of symptom. Note resolved hyperechoic periappendiceal fat infiltration. 32

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 으로알려져있다. 임상적으로증상이회복된환자중에서재발률이 38% 로알려져있고시기는평균 14주였고 70% 에서는 1년이내에재발되었다. 특히남성, 충수의직경이 8 mm 이상그리고장간막림프절비후가없었던군에서는재발률이 60% 로높아서이들의경우즉각적인수술을권유하였다 [92]. 하지만증상이거의호전된환자에서수술을꺼리는경우에는증상이재발시즉각적인병원내원을권유하여야한다. 만성충수염 (chronic appendicitis, Fig. 26) 만성충수염은전체급성충수염환자에서 1.5% 빈도로나타나며 [93], 충수의지속적인불완전한폐쇄로인하여충수에만성적인염증반응을일으키는것으로수주이상지속되는심하지않은지속적인우하복부통증이특징이다 [94,95]. 만성충수염의진단은다른원인이없이 3주이상의우하복부통증이있 고, 병리학적으로충수벽의만성염증세포침윤과충수의섬유화소견이있어야하고충수절제술로서증상의완전한호전이있으면가능하다 [91,94-96]. 재발성충수염 (recurrent appendicitis) 재발성충수염은 2회이상의재발되는급성충수염으로정의하는데, 초기증상은 24-48시간이내에저절로회복되고각각의사건사이에는증상이없는것이특징이다 [95]. 잔존충수염 (stump appendicitis, Fig. 27) 충수염으로충수절제술을시행받았던환자에서남아있던맹장기저부위의충수절단면에서재발한염증으로서최근에복강경하충수절제술이보편화됨에따라충수절제술의과거력이있는환자에서도우하복부통증의원인으로잔존충수염의가 C Figure 26. 59-year old male with chronic appendicitis. () Transverse section of appendix (calipers) showed round distended with maximal outer diameter of 10.2 mm. Note echogenic appendicolith (arrow) with acoustic shadowing. ut definite periappendiceal fat infiltration was not identified. () Longitudinal section of appendix (calipers) demonstrated distended appendix (calipers) with preserved submucosal layers throughout the entire length of the appendix. (C) Longitudinal color doppler image of appendix (arrow). Note mild intramural hyperemia within the wall of the appendix. He complained chronic right lower quadrant pain for several months. Laparoscopic appendectomy was performed which revealed acute and chronic appendicitis on pathology (not shown). C Figure 27. 23-year old female with stump appendicitis. () Transverse view of cecum demonstrates wall thickening, especially echogenic submucosal layer (long arrow). () Transverse view of right iliac fossa. Remnant appendix (long arrow) was identified at inferior to the cecum. lso periappendiceal abscess () is also observed. (C) Longitudinal view of right iliac fossa. 2.2 x 1.8 cm sized abscess cavity () was observed at inferior to the cecum. Note cecal wall thickening (long arrow)., abscess. 33

Clinical Ultrasound Vol. 1, No. 1, May 2016 능성을염두해두어야한다 [97]. 잔존충수염의임상양상은일반적인충수염과동일하다. 다만충수절제술의과거력때문에진단과정에서다른질환을먼저생각하는경우가있어서이로인한진단의지연으로약 70% 의환자에서는천공후발견되는경우가많다 [98,99]. 복강경충수절제술당시에염증이심하여불완전절제를한경우나충수-맹장접합부를충분히확인하지못하고수술한경우, 5 cm 이상의잔존충수를남기는경우에서그빈도가증가되므로복강경충수절제술시에충수기저부를확인하지못하는경우개복수술로전환하고남아있는충수기저부가 3 mm를넘지않도록권고하고있다 [98,99]. 진단방법은초음파보다는다중검출복부전산화단층촬영 (multi-detector computed tomography) 을통한경우가더많았으나 [100-102], 최근고해상도초음파검사의도입으로초음파검사로진단이가능 하다. 대부분우하복부의맹장주위의염증, 농양, 체액저류, 염증성종괴등의간접적인소견을보이고, 잔존충수의길이가충분하지않은경우에는술전진단이어렵다. 충수게실염 (appendiceal diverticulitis, Fig. 28) 충수의게실염은충수벽의게실에서발생한염증을말하는데빈도는수술환자의 0.2-1.5% 로아주드문질환이며 [103] 임상양상이급성충수염과감별이어려운경우가많아서수술후진단되는경우가많고수술전초음파로진단되는경우는드물다. 충수염에비해발병연령이높고, 복통의지속기간이긴편이다 [104]. 초음파소견은정상충수에생긴게실내저에코성염증, 게실입구의고에코의분석, 그리고충수게실주변의고에코성염증성지방조직등이있다. 충수게실은후천적으로장관내 C Figure 28. 67-year old femle with appendiceal diverticulitis. () Longitudinal section of normal proximal appendix. Note the well-preserved submucosal layer (long arrow) () Transverse section of distal portion of appendix (long arrow) showed normal caliber with lateral hypoechoic diverticular sac (D). Note peridiverticular hyperechoic fat infiltration (short arrow). (C) On color doppler study of same patient, mildly increased blood flow (arrow) is observed within the wall of appendiceal diverticum (D). D, appendiceal diverticulum. Figure 29. 72-year old male with secondary appendicitis due to cecal cancer. () Note irregular hypoechoic wall thickening and mass (arrow) of cecum (C) and ileocecal valve (ICV) obstructing appendiceal orifice. () Longitudinal section of appendix (long arrows) showed markedly distended appearance with cystic lesion at tip (short arrow). Note irregular hypoechoic mass at cecum invading psoas muscle. ICV, ileocecal valve; C, cecum. 34

Dae Hyun Kim. Ultrasonography of appendicitis Clinical Ultrasound 압의증가로인해서충수벽내로관통동맥이들어가는부위에 서점막과점막하층이외벽으로돌출되는가성게실로서 60% 에서는충수의원위부에서발생하고급성충수염에비해서천 공이잘되는것이특징이다 [105]. 충수의게실성질환은 4 가지 형태로구분하여기술한바있는데 [106] 이는 1) appendiceal diverticula without inflammation, 2) acute appendicitis with appendiceal diverticula, 3) acute appendiceal diverticulitis with acute appendicitis, 4) acute appendiceal diverticulitis 이며이중 에서 4 번째가진정한충수게실염에해당된다. 우측결장암에의한급성충수염 (acute appendicitis secondary to cecal cancer, Fig. 29) 맹장에서발생한악성종양은종양자체에의한충수입구의 폐쇄, 종양의파급에의한충수외부압박, 종양의충수조직으 로의직접침윤그리고종양에의한장벽의천공으로인한충수 주위농양의형성을유발할수있다 [107]. 일반적인충수염과같 이충수의종대, 충수주위의염증성고에코의지방조직과더불 어맹장종양에의한맹장벽비후, 종괴형성, 림프절비후등의 소견을관찰할수있다. 맹장종양에의한충수입구의폐쇄로 무균의점액이고이게되고충수의확장에비해서우하복부통 증이나압통이상대적으로경미한경우또는 50 세이상의충수 염환자에서우측대장암에의한 2 차성충수염을의심할수있 다 [63,108]. 결론 충수염은진단이늦어질경우천공의합병증이생길수있는 질환으로환자의증상및이학적인소견과함께초기에적극적 인초음파검사를함으로써진단율을높일수있다. 특히소화 관초음파의기본원리를잘이해하고계통적인방법으로충수를 스캔하는연습을꾸준하게함과동시에본고에서기술한다양 한충수염의초음파소견을숙지한다면하복부통증환자에서 충수염의진단율을높일수있을것이다. 중심단어 : 초음파 ; 충수 ; 충수염 REFERENCES 1. Neutra RR. ppendicitis: decreasing normal removals without increasing perforations. Med Care 1978;16:956-961. 2. Nelson MJ, Pesola GR. Left lower quadrant pain of unusual case. J Emerg Med 2001;20: 241-245. 3. Humes DJ, Simpson J. cute appendicitis. MJ 2006;333:530-534. 4. cheson J, anerjee J. Management of suspected appendicitis in children. rch Dis Child Educ Pract Ed 2010;95:9-13. 5. Vignault F, Filiatrault D, randt ML, Garel L, Grignon, Ouimet. cute appendicitis in children: evaluationwith US. Radiology 1990;176:501-504. 6. ng, Chong NK, Daneman. Pediatric appendicitis in real-time : the value of sonography in diagnosis and treatment. Pediatr Emerg Care 2001;17:334-340. 7. Lamps LW. ppendicitis and infections of the appendix. Semin Diagn Pathol 2004;21:86-97. 8. Lamps LW. Infectious causes of appendicitis. Infect Dis Clin North m 2010;24:995-1018, ix-x. 9. Williams R, Myers P. Pathology of the appendix and its surgical treatment. 1st ed. London: Chapman and Hall Medical press, 1994. 10. Quigley J, Stafrace S. Ultrasound assessment of acute appendicitis in pediatric patients: methodology and pictorial overview of findings seen. Insights Imaging 2013;4:741-751. 11. Puylaert J. cute appendicitis: US evaluation using graded compression. Radiology 1986;158:355-360. 12. Oh KJ, Cho JS, Shin KS, et al. Normal appendix in adults: MDCT findings about the location, thickness and the presence or absence of intraluminal gas. J Korean Radiol Soc 2006;55:373-379. 13. Vignault F, Filiatrault D, randt ML, Garel L, Grignon, Ouimet. cute appendicitis in children: evaluation with US. Radiology 1990;176:501-504. 14. Rioux M. Sonographic detection of the normal and abnormal appendix. JR m J Roentgenol 1992;158:773-778. 15. Goldin, Khanna P, Thapa M, Mcroom J, Garrison MM, Parisi MT. Revised ultrasound criteria for appendicitis in children improve diagnositic accuracy. Pediatr Radiol 2011;41:993-999. 16. Rettenbacher T, Hollerweger, Macheiner P, et al. Outer diameter of the vermiform appendix as a sign of acute appendicitis: evaluation at US. Radiology 2001;218;757-762. 17. Simonovský V. Normal appendix: is there any significant difference in the maximal mural thickness at US between pediatric and adult populations? Radiology 2002;224:333-337. 18. irnbaum, Wilson SR. ppendicitis at the millennium. Radiology 2000;215:337-348. 19. Sivit CJ. Diagnosis of acute appendicitis in children: spectrum of sonographic findings. JR m J Roentgenol 1993;161:147-152. 20. Sivit CJ, Siegel MJ, pplegate KE, Newman KD. When appendicitis is suspected in children. Radiographics 2001;21:247-262; questionnaire 288-294. 35

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