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Korean J Gastroenterol Vol. 64 No. 1, 4-9 http://dx.doi.org/10.4166/kjg.2014.64.1.4 pissn 1598-9992 eissn 2233-6869 REVIEW ARTICLE 트림 류한승 *, 최석채 *, 이준성 1 원광대학교의과대학소화기질환연구소, 내과학교실, 순천향대학교의과대학소화기연구소, 내과학교실 1 Belching (Eructation) Han Seung Ryu*, Suck Chei Choi* and Joon Seong Lee 1 Department of Internal Medicine, Digestive Disease Research Institute, Wonkwang University College of Medicine, Iksan, Department of Internal Medicine, Institute for Digestive Research, Soonchunhyang University College of Medicine, Seoul 1, Korea Belching is a normal physiological function that may occur when ingested air accumulated in the stomach is expelled or when food containing air and gas produced in the gastrointestinal tract is expelled. Excessive belching can cause patients to complain of abdominal discomfort, disturbed daily life activities, decreased quality of life and may be related to various gastrointestinal disorders such as gastroesophageal reflux disease, functional dyspepsia, aerophagia and rumination syndrome. Belching disorders can be classified into aerophagia and unspecified belching disorder according to the Rome III criteria. Since the introduction of multichannel intraluminal impedance monitoring, efforts are being made to elucidate the types and pathogenic mechanisms of belching disorders. Treatment modalities such as behavioral therapy, speech therapy, baclofen, tranquilizers and proton pump inhibitors can be attempted, but further investigations on the effective treatment of belching disorders are warranted. (Korean J Gastroenterol 2014;64:4-9) Key Words: Eructation; Electric impedance; Lower esophageal sphincter 서론 트림은식도에서인두 (pharynx) 로기체가소리를내며나오는현상이다. 정상인은식후간헐적인트림을하며불편감을느끼거나병적상태로여기지않고질병연관성은드물다. 그러나증상이갑자기발생하고조절되지않거나빈번하여불편감및일상생활의어려움을호소하며심각한상태로인지하여의사를방문하기도한다. 병적상태의트림은병의발생및임상적인관심이낮지만위식도역류질환, 1-6 기능성소화불량증, 6-8 공기삼킴증 (aerophagia), 9 되새김증후군 (rumination syndrome) 10 등다양한위장관질환과동반되거나단일질환으로발생가능하며기저질환의증상악화및삶의질저하로 연결될수있다. 11 트림의생리기전과병적상태에관한연구는식도내기체의흐름을파악할수있는다채널강내임피던스검사 (multichannel intraluminal impedance monitoring) 가도입되면서개념이정립되고있다. 이글에서는트림의생리기전, 병태생리에근거한분류및치료의관점에대하여살펴보고자한다. 본론 1. 트림의생리음식물을섭취하는과정에서삼켜진공기나음용한탄산음료등에포함된기체는위의근위부에모이며이를감지하여 CC 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. *These authors contributed equally to this study. This article is based on a presentation at Clinical Symposium of The Korean Society of Neurogastroenterology and Motility (October 27, 2013). 교신저자 : 이준성, 140-743, 서울시용산구대사관로 59, 순천향대학교서울병원소화기연구소 Correspondence to: Joon Seong Lee, Institute for Digestive Research, Soonchunhyang University College of Medicine, 59 Daesagwan-ro, Yongsan-gu, Seoul 140-743, Korea. Tel: +82-2-709-9691, Fax: +82-2-709-9696, E-mail: joonlee@schmc.ac.kr Financial support: This work was supported by a grant from Wonkwang University 2012 (SC Choi). Conflict of interest: None. Korean J Gastroenterol, Vol. 64 No. 1, July 2014 www.kjg.or.kr

Ryu HS, et al. Belching (Eructation) 5 Fig. 1. Mechanism of belching. The ingested air during swallowing of food and water accumulates in the proximal stomach. Increased volume in proximal stomach induces transient lower esophageal sphincter relaxation (tlesr), followed by rapid moving of gastric air into the esophagus. Abrupt distension of esophagus by refluxed air induces secondary peristalsis or esophago-ues relaxation reflex, which allows venting of gas. LES, lower esophageal sphincter; UES, upper esophageal sphincter. 배출하는과정이트림이다. 건강한성인을대상으로전산화단층촬영을이용한연구에서 10 ml의액상식괴를삼키는동안약 17 ml (8-32 ml) 의공기가동시에삼켜진다. 12 삼켜진공기는위근위부에모이게되고확장된근위부위벽내의신전수용체를활성화시켜미주신경반사를촉발한다. 13 흥분된미주신경배측운동핵 (dorsal motor nucleus) 은원심성미주신경및횡격막신경 (phrenic nerve) 을활성화시켜하부식도조임근및횡격막각 (crural diaphragm) 으로구성된항역류장벽을이완하면서압력차와비중에의해서위속의공기가빠져나가는일과성하부식도조임근이완 (transient lower esophageal sphincter relaxation) 을유발한다. 14 동시에식도의종주근 (longitudinal muscle) 및복직근 (rectus abdominis) 이수축되어위에서식도로기체의이동을도우며, 갑자기많은양의기체가식도를팽창시킴으로써이차성연동운동이발생하여식도내의공기가다시아래쪽순방향으로밀려내려가거나또는식도-상부식도조임근이완반사 (esophagoupper esophageal sphincter [UES] relaxation reflex) 를유발하여인두부근육및상부식도조임근이이완되어기체가인두로나오면서트림이발생한다 (Fig. 1). 15-17 정상생리작용의일환으로서의트림은불수의적현상이며, 18 위의감압및장내불필요한공기의축적을방지하는기능을한다. 19 2. 트림의병태및분류생리적트림과동일한기전으로기체가위에모인후식도를통해이동하여트림이발생하는경우를위트림 (gastric belching) 으로분류할수있다 (Fig. 2A). 19,20 과도한위트림은위로유입되는공기량을증가시키는빠른식습관이나껌, 탄산음료등의과도한섭취, 위배출능저하, 유문부이하장관의기질적및기능적폐쇄시에발생할수있으며병적상태로인지되는경우는드물지만간혹일상생활을할수없을정도로심한경우도있다. 3,5,21-23 일부환자들은위내의공기를분출하기보다는공기를인두부또는횡격막근육의수축을통하여인위적으로빨아들인후 1초이내에즉시배출하는위상부트림 (supragastric belching) 의형태를보이기도한다. 이때삼켜진공기는하부식도조임근을통과하지않고짧은순간식도내에머물다가팽창된상부식도에의한식도-상부식도조임근이완반사를통해즉시분출된다 (Fig. 2B). 19 식도-상부식도조임근이완반사는식도가천천히팽창할때발생하는식도-상부식도조임근수축반사 (esophago-ues contractile reflex) 와달리식도벽의빠른신전으로유발되는데점막의기계적수용체의자극에의한미주신경반사로발생한위상부트림은다채널강내임피던스검사를통해식도내공기의흐름을식별하는방법으로진단가능하다. 22 발생기전은, 환자가성문을닫은채횡격막근육을수축시켜숨을들이쉬면서흉강및식도내에음압을 Vol. 64 No. 1, July 2014

6 류한승등. 트림 Fig. 2. Types and mechanisms of belching. (A) Gastric belching. The ingested air that accumulates in the stomach or gas that is generated from food or gastrointestinal tract is expelled during relaxation of the lower esophageal sphincter. (B) Supragastric belching. The ingested air does not enter the stomach but is expelled immediately. (C) Aerophagia. As patients swallow air continuously, some portion of the air is vented by gastric belching and moves to the intestine, causing abdominal distention. (D) Rumination syndrome. The voluntary contraction of the abdominal wall musculature increases intragastric pressure, thereby causing reflux of gastric contents into the esophagus and venting of air simultaneously. 형성하고상부식도조임근을이완시켜식도내로공기를유입시킨후즉시인두방향으로공기를밀어내거나 (air sucker), 설하및인두부근육을수축시켜공기를식도로밀어넣는 (air pusher) 경우로제시되고있다. 22,24 위상부트림의병인으로불안및스트레스, 25 강박성성격장애, 26 신경성과식증 (bulimia nervosa) 27 등의정신과적질병과의연관성이제시되었다. 특히환자의수면시에는증상이발생되지않으며, 28 환자의정신적이완상태에서는증상발생이감소하는경향이있어 29 행동장애의일환일가능성이알려져있다. 30 그러나현재까지정신병태생리에대한잘고안된연구가없기에독립적인병인으로단정하기어렵다. 위산역류와의관련성은불명확하나위식도역류질환에서역류의가장흔한기전이트림과동일한일과성하부식도조임근이완이라는점에서깊은관련이있고, 실제위식도역류질환의약 50% 에서과도한트림을한다. 1 위식도역류질환 12명과건강자원자를대상으로한연구에서, 위식도역류질환환자의산역류발생은공기삼킴이나위내에저류된공기의양, 트림빈도와무관하였지만, 공기삼킴및트림의빈도가높았다. 2 전형적인역류증상을가지는환자 50명중 24명에서위상부트림이관찰되었는데이중 18% 는위산역류이후에트림증상이발생되었다. 3 불편감을주는트림은위상부트림이며위트림에서는증상을호소하지않는경우가많다. 5 가능한가설로위산역류로인한불편감이인위적인공기삼킴을일으키고이를제거하는과정에서위상부트림이발생하는것으로추측해볼수있다. 그러나두배용량의양성자펌프억제제를투여 한연구에서공기삼킴의빈도를감소시키지못하였다. 4 트림은조기포만감 (satiation), 팽만감 (bloating), 복부불편감등과같은기능성소화불량증의증상과도함께나타난다. 기능성소화불량증환자가왜지나친트림을호소하는지는명백하지않다. 때로는팽만감을호소하는환자가트림으로팽만감이좋아진다고보고하기도한다. 트림은주관적으로호소하는경우가많으므로기능성소화불량증환자에서실제로트림의빈도가높은지는아직잘알수없다. 3. 감별진단공기삼킴증 (aerophagia) 은로마기준 (Rome criteria) 에서객관적인공기삼킴이관찰또는측정되고반복적인트림이있는경우로트림장애 (belching disorders) 의하부영역으로분류되며, 31 행동장애의일환으로생각된다. 32 트림장애의로마 III 진단기준은공기삼킴증의경우 1) 일주일에적어도수차례반복되는불편한트림, 2) 공기를삼키는것이객관적으로관찰되거나측정된경우로, 적어도 6개월전에증상이시작되었고지난 3개월동안상기진단기준을모두만족하는경우로진단한다. 비특이적과다트림 (unspecified excessive belching) 의경우는 1) 일주일에적어도수차례반복되는불편한트림, 2) 공기를과다하게삼킨다는증거가없는경우로, 적어도 6개월전에증상이시작되었고지난 3개월동안상기진단기준을모두만족하는경우로진단한다. 31 트림증상이외에지속적으로삼켜진공기에의한과도한위장관내공기축적때문에복부팽만및불편감, 통증, 방귀 The Korean Journal of Gastroenterology

Ryu HS, et al. Belching (Eructation) 7 등이주증상으로나타날수있다. 발생기전은식도내로흡입된공기가하부식도조임근이하부위의장관에지속적으로축적되는것이며일부의공기가위트림의형태로배출될수있다 (Fig. 2C). 공기삼킴증에대한임피던스연구에서공기삼킴과위트림이관찰되었으나위상부트림은관찰되지않았다. 9 영상검사에서는삼킨공기가바로분출되는위상부트림에서는장관내공기축적이없지만공기삼킴증에서는축적된장관내공기가관찰되는차이가있다. 30 임상적으로위상부트림과위트림의감별점으로는위트림은생리적인트림으로빈도는시간당 4회까지나타나고, 주로식사후, 특히탄산음료를마신후에잘발생하며, 트림시에먹은음식이나음료수위산의냄새가나고, 트림소리가종종안들리기도하고, 위식도역류질환이나기능성소화불량증과동반되는일이잦다. 반면에위상부트림은병적인트림으로분당 20회까지아주잦은빈도로나타날수있고, 음식섭취와관련이없으며, 냄새가나지않고, 트림소리가아주시끄럽고조절하기가힘들어대인생활이힘들며따라서일상생활에많은지장을초래하고불안증이나신경증이잘동반된다는점에서차이가있다. 21 되새김증후군 (rumination syndrome) 은만성섭식장애로섭취한음식물을역류시켜다시저작하여삼키거나배출하는드문질환이다. 31-33 대개트림과감별이어려운경우는드물지만확실한진단을위해시행하는식도내압검사에서는트림과역류가동반될경우공통강 (common cavity) 과되새김증후군에서관찰되는 R파 (R wave) 가감별이어려운경우가있다. 34 발생기전은복부근육의수의적수축을통하여위내압력을증가시켜위내용물을식도로역류시키는것으로추정된다 (Fig. 2D). 33,34 불안, 우울및강박장애등정신과적질환과연관성이있고구취, 치아우식증, 체중감소등의증상이동반될수있으며, 34 위의음식물역류시트림이동반될수있다. 되새김증후군과트림-역류는역류된물질의성상및위내압력 증가와식괴의역류에대한식도임피던스-내압검사를통한분석으로감별할수있다. 10,33 4. 치료과도한트림은중증질환으로발생가능하나환자가인지하는증상의심각성에대한의료진과주변의이해가부족한경우가많으며많은의료기관을거쳐방문하기도한다. 트림으로인하여일상생활의장애및삶의질저하를일으키는경우치료가필요하다. 11 위식도역류질환이나기능성소화불량증환자에서지나친트림이동반된경우트림에대한치료보다는이들질환을먼저치료해보는것이좋다. 동반된위장관질환이없는위트림은환자를안심시키고식사습관교정및위장관운동촉진제를시도해볼수있다. 식사습관교정으로는단단한사탕을빨거나껌을씹지않도록하고, 식사를천천히하면서작게삼키도록하며, 탄산음료를금한다. 위상부트림의경우행동장애및위산역류등과의연관성을설명하지만환자들이쉽게이해하기어려운경우가많다. 24 스트레스, 불안, 우울및정신과적동반질환등이의심된다면협진이필요하다. 치료에대한잘계획된연구는부족하지만인지행동치료 (cognitive behavior therapy) 는환자에게트림증상이환자에게학습된행동임을인식시키고이완및증상을촉발시키는인자에대한인지를향상시킴으로써치료효과를나타낼수있다. 32 최근제시된외래에서시행할수있는행동치료의기법을이용한방법은환자에게천천히가로막을이용한복식호흡을하도록하면서누워있는자세에서입을크게벌리게하여위상부트림의발생을억제하는것이다. 35 이러한가로막호흡 (diaphragmatic breathing) 은한번에 30분정도씩하며환자의배에치료자의손을얹어서숨쉴때복근이이완되는지확인하면서들숨을날숨보다더길게들이쉬도록하는것이요령이다. 이러한방법은임상적용이쉽고병태생리에 Table 1. Clinical Workup and Therapeutic Modalities of Belching History Physical examination Abdominal radiograph Esophageal impedance monitoring (and combined manometry) Upper endoscopy on indication Therapy Frequency of belching, occurrence of belching after meal, during sleep or other activities, scent or taste of belching, audible (loud or not), effect of stress, reflux symptoms, dyspepsia, signs of psychiatric comorbidity, perceived symptom severity, impact of psychosocial aspect and quality of life Exclude other causes, thorough examination of neck and abdomen, inspection of air swallowing No abnormalities in supragastric belching Supragastric or gastric belches, differential diagnosis of aerophagia and rumination syndrome Behavior therapy Speech therapy Baclofen Proton pump inhibitor Data from the articles of Bredenoord (Clin Gastroenterol Hepatol 2013;11:6-12/Dis Esophagus 2010;23:347-352). 24,30 Vol. 64 No. 1, July 2014

8 류한승등. 트림 근접한방법이라고생각한다. 언어치료 (speech therapy) 는일부위상부트림환자에서병태생리에대해잘인지하고있는언어치료사가참여하는경우반응이있었다. 언어치료의개념은구인두수술후특히후두암으로후두절제술을시행받은환자에서정상적인발성이불가능하므로식도내로공기를흡입한후즉시배출하여식도발성을하게하는데이러한과정에대한이해를토대로위상부트림의과정을역으로차단하는것이다. 36 Baclofen은 GABA B 수용체작용제로일과성하부식도괄약근이완을차단하고공기삼킴의빈도를감소시켜위상부트림및공기삼킴증에효과적일수있다. 34,37-39 양성자펌프억제제는위산역류증상이있는환자에서공기삼킴의빈도는줄이지못하였으나, 4 위산역류와트림증상과의연관성이의심되는경우시도해볼수있다. 심한트림의경우신경안정제를요하기도한다. 일부에서최면치료 (hypnosis), 40 바이오피드백 41 등을적용한보고가있고최근에는임피던스카테터를이용한바이오피드백치료가시도되고있다. 결 론 트림은정상생리작용의일환이지만소수의환자에서병적상태로발현되기도한다. 병력청취및신체검사를통하여다양한위장관및정신과적질환의동반가능성에대하여고려해야한다. 다채널강내임피던스-내압검사로발생기전에대한이해와감별진단이가능하다 (Table 1). 위트림은생활습관교정및동반된위장관질환에대한검사가필요하며, 위상부트림은행동장애, 위산역류및정신과적동반질환에대한평가등보다세밀한진단적접근이필요할수있다. 치료로는행동치료, 언어치료, baclofen, 양성자펌프억제제등이시도되고있다. REFERENCES 1. Klauser AG, Schindlbeck NE, Müller-Lissner SA. Symptoms in gastro-oesophageal reflux disease. Lancet 1990;335:205-208. 2. Bredenoord AJ, Weusten BL, Timmer R, Smout AJ. Air swallowing, belching, and reflux in patients with gastroesophageal reflux disease. Am J Gastroenterol 2006;101:1721-1726. 3. Hemmink GJ, Bredenoord AJ, Weusten BL, Timmer R, Smout AJ. Supragastric belching in patients with reflux symptoms. Am J Gastroenterol 2009;104:1992-1997. 4. Hemmink GJ, Weusten BL, Bredenoord AJ, Timmer R, Smout AJ. Increased swallowing frequency in GORD is likely to be caused by perception of reflux episodes. Neurogastroenterol Motil 2009;21:143-148. 5. Kessing BF, Bredenoord AJ, Velosa M, Smout AJ. Supragastric belches are the main determinants of troublesome belching symptoms in patients with gastro-oesophageal reflux disease. Aliment Pharmacol Ther 2012;35:1073-1079. 6. Lin M, Triadafilopoulos G. Belching: dyspepsia or gastroesophageal reflux disease? Am J Gastroenterol 2003;98:2139-2145. 7. Tack J, Caenepeel P, Fischler B, Piessevaux H, Janssens J. Symptoms associated with hypersensitivity to gastric distention in functional dyspepsia. Gastroenterology 2001;121:526-535. 8. Conchillo JM, Selimah M, Bredenoord AJ, Samsom M, Smout AJ. Air swallowing, belching, acid and non-acid reflux in patients with functional dyspepsia. Aliment Pharmacol Ther 2007;25: 965-971. 9. Hemmink GJ, Weusten BL, Bredenoord AJ, Timmer R, Smout AJ. Aerophagia: excessive air swallowing demonstrated by esophageal impedance monitoring. Clin Gastroenterol Hepatol 2009; 7:1127-1129. 10. Rommel N, Tack J, Arts J, Caenepeel P, Bisschops R, Sifrim D. Rumination or belching-regurgitation? Differential diagnosis using oesophageal impedance-manometry. Neurogastroenterol Motil 2010;22:e97-e104. 11. Bredenoord AJ, Smout AJ. Impaired health-related quality of life in patients with excessive supragastric belching. Eur J Gastroenterol Hepatol 2010;22:1420-1423. 12. Pouderoux P, Ergun GA, Lin S, Kahrilas PJ. Esophageal bolus transit imaged by ultrafast computerized tomography. Gastroenterology 1996;110:1422-1428. 13. Penagini R, Carmagnola S, Cantù P, Allocca M, Bianchi PA. Mechanoreceptors of the proximal stomach: Role in triggering transient lower esophageal sphincter relaxation. Gastroenterology 2004;126:49-56. 14. Mittal RK, Fisher MJ. Electrical and mechanical inhibition of the crural diaphragm during transient relaxation of the lower esophageal sphincter. Gastroenterology 1990;99:1265-1268. 15. Lang IM, Medda BK, Shaker R. Digestive and respiratory tract motor responses associated with eructation. Am J Physiol Gastrointest Liver Physiol 2013;304:G1044-G1053. 16. Babaei A, Bhargava V, Korsapati H, Zheng WH, Mittal RK. A unique longitudinal muscle contraction pattern associated with transient lower esophageal sphincter relaxation. Gastroenterology 2008;134:1322-1331. 17. Shaker R, Ren J, Kern M, Dodds WJ, Hogan WJ, Li Q. Mechanisms of airway protection and upper esophageal sphincter opening during belching. Am J Physiol 1992;262:G621-G628. 18. Bredenoord AJ, Weusten BL, Timmer R, Akkermans LM, Smout AJ. Relationships between air swallowing, intragastric air, belching and gastro-oesophageal reflux. Neurogastroenterol Motil 2005;17:341-347. 19. Bredenoord AJ, Weusten BL, Sifrim D, Timmer R, Smout AJ. Aerophagia, gastric, and supragastric belching: a study using intraluminal electrical impedance monitoring. Gut 2004;53: 1561-1565. 20. Sifrim D, Silny J, Holloway RH, Janssens JJ. Patterns of gas and liquid reflux during transient lower oesophageal sphincter relaxation: a study using intraluminal electrical impedance. Gut 1999;44:47-54. The Korean Journal of Gastroenterology

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