Review Article J Clin Nutr 2014;6(1):19-23 ISSN 2289-0203 소아단장증후군의영양지원 송지영 1, 김현영 2 1 서울대학교병원급식영양과, 2 서울대학교어린이병원소아외과 Ji-Young Song 1, Hyun-Young Kim 2 1 Department of Food Service and Nutrition Care, Seoul National University Hospital, 2 Department of Pediatric Surgery, Seoul National University Children s Hospital, Seoul, Korea Short bowel syndrome (SBS) develops in infants and children with inadequate small intestine for digestion and absorption of enteral nutrients for normal growth and development. This can lead to malabsorption of macronutrients or micronutrients, electrolyte imbalance, dehydration, malnutrition, and growth failure. The goals of nutrition support in pediatric SBS are to promote intestinal adaptation, avoid complications associated with intestinal resection and parenteral nutrition (PN), and, ultimately, maintain normal growth. In the initial phase of SBS, PN support is important in order to meet energy requirements and for avoidance of electrolyte imbalance or dehydration. Enteral nutrition should be initiated as soon as possible after bowel resection in order to promote intestinal adaptation. In order to stimulate oral motor activity and to avoid feeding aversion behavior, tolerable volumes of bottle-feeding or solid food should be accepted. In addition, feeding volume might be gradually increased in small amounts with monitoring of stool quantity and consistency. Because not all enterally administered calories are absorbed, PN should not be decreased isocalorically against enteral nutrition. In order to enhance bowel adaptation by maximizing nutrient delivery, it is necessary to determine the potential advantages of administration mode, continuous vs. bolus feeding, and what formula should be considered, polymeric vs. monomeric or oligomeric formula. Optimal enteral feeding regimen for pediatric SBS is still being debated, how to feed or what to feed, therefore, nutritional management of SBS should be adjusted according to the patient s medical condition. Key Words: Short bowel syndrome, Nutritional support, Child 서 론 Received Apr 3, 2014; Revised Apr 8, 2014; Accepted Apr 8, 2014 Correspondence to Hyun-Young Kim Department of Pediatric Surgery, Seoul National University Children s Hospital, 101, Daehak-ro, Jongno-gu, Seoul 110-744, Korea Tel: +82-2-2072-2478, Fax: +82-2-766-3975, E-mail: spkhy02@snu.ac.kr Conflict of interest: None. 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. 단장증후군은여러가지원인으로인해장내영양소의흡수표면적이줄어들고음식물이장을통과하는시간이빨라져탈수, 전해질이상, 영양소흡수불량등을초래하는질환으로소아의경우성장, 발육을위해서적절한영양지원이필수적이다. 단장증후군환자의영양지원의목적은세균증식, 감염, 대사적합병증등의예방과더불어남아있는장의적응도를높이는것이며, 남아있는장의적응정도가단장증후군소아의삶의질과예후에큰영향을미치게된다. 1,2 c 2014, The Korean Society for Parenteral and Enteral Nutrition. All Rights Reserved.
Ji-Young Song and Hyun-Young Kim 이에본저자들은소아의단장증후군에대한소개와효과적인영양지원에대해국내외문헌들을조사하였다. 본론 1. 소아의단장증후군단장증후군은선천성또는생후수술적절제로전체소장의 50% 이상이소실되어흡수장애와영양실조를일으키는상태이다. 2 실제로저자에따라정의가다양하지만최근논문에의하면장기능이정상인소아는재태연령에따라 50% 이하의장소실에대해서는잘견딜수있다는보고등 3,4 을근거로하여상기정의가합당한것으로여겨지고있다. 단장증후군은십만명에 1,200명정도에서발생하며, necrotizing enterocolitis, intestinal malrotation, multiple intestinal atresias, gastroschisis, aganglianosis 등이원인으로알려져있다. 신생아의장길이는평균 250 cm이며, 성인이되면 6 8 m 정도로길어진다. 또한태아의경우제2삼분기에서 3삼분기로넘어가는시기에장길이가 2배로성장하며, 생후첫 1년동안가장많이길어진다. 1 따라서어린시기에장을절제하면성인에비해적은절제길이로도큰손실을입는반면회복가능성도성인에비해많게된다. 그외에단장증후군의병태생리에는장의어떤부분이절제되었느냐가영향을미치게된다. 예를들어십이지장이절제되는경우철분, 칼슘, 엽산흡수의문제가발생할수있고공장의절제시유당불내성, 췌장효소의불활성화등이일어날수있다. 회장이절제되면다량의수분손실및전해질불균형, 담즙산및비타민흡수장애, 설사및발육지연이일어날수있다. 회맹판이절제되면대장의균이소장으로쉽게넘어와장염이자주발생하며, 장내용물의장통과시간이짧아져흡수장애가자주일어나게된다. 따라서단장증후군을진단할때는수술력을잘살펴어느부분이어느정도절제가되었는지확인하는것이중요하다. 그외에설사, 몸무게감소, 영양실조, 피로, 발육지연등이있을수있으며, 이학적검사결과는부족한영양소의종류에따라다르게나타날수있다. 특히혈중 citrulline은장에서합성되는비단백아미노산으로서, 19 mmol/l 이하인경우에는장의자율성이저하될가능성이많아단장증후군의진단에있어서참고로사용할수있는수치이다. 5 단장증후군의치료는크게내과적치료와외과적치료로나눌수있다. 내과적치료에서가장중요한것은수분보충과전해질균형을유지하는것이다. 이외에위액분비감소를위한 H2 blocker 제제나설사를줄이기위해 codein, octreotide의사용도고려 해볼수있다. 2,3 절제후의장은약 2일에서부터길게는 18개월까지적응의기간을가지며, 이기간내에충분히적응하지못하면수술적치료를고려해볼수있다. 수술의종류는크게비이식술식과이식술식으로나뉜다. 비이식수술방법은 colonic interposition, serial transverse enteroplasty (STEP), longitudinal intestinal lengthening and tailoring (Bianchi procedure) 등이있다. Colonic interposition은소장이늘어나지않은환자에게유용한방법이며, 구불결장의 8 15 cm를절제하여방향을돌린후잘린소장에연결하여장통과시간을지연시킨다. 6 장이늘어나있는경우에는 STEP이나 Bianchi procedure가선호되는데, 전자는복강경으로수술이가능하고후자는장표면적을더많이늘릴수있다는특징이있다. 7 장이식의적응증은크게생명이위태로운합병증이있거나, 극심한탈수, 중심정맥관과관련된합병증이반복적으로발생하는경우이다. 8 이식의방법으로는장만따로이식하는방법과장과간을동시에이식하는방법, 마지막으로다종장기이식, 즉장, 췌장, 간을동시에이식하는방법이있다. 8 이식후합병증으로는면역거부반응, 감염, 다발성장기부전, 면역억제와관련한여러합병증들이있다. 장이식의성적은장단독이식의경우이식편 1년생존율약 60% 70%, 이식편 3년생존율약 50% 60% 이며, 장-간복합이식의경우이식편 1년생존율약 70% 80%, 이식편 3년생존율약 50% 60% 정도로알려져있다. 9 2. 영양지원단장증후군의영양지원은비경구즉경정맥영양과경장영양이있다. 초기에는경정맥영양지원을시행하고, 가능한빠르게경장영양지원을시작하여미세융모의증식을꾀하며장의적응력을높일수있도록하여야한다. 1) 경정맥영양지원-수액, 전해질, 정맥영양단장증후군환자는장의성장과적응이이루어져경구식이만으로영양공급이가능해지기전까지는정맥영양을통해영양지원이이루어져야한다. 수술후단장증후군이예상될때조기에수분과전해질의균형을유지하는것이중요하다. 보통흡수면적의감소로인해대량의수분소실이흔하며혈중나트륨성분이저하되는경향을보이므로적어도 80 100 meq/l 나트륨을포함한정맥영양이전해질균형을유지하기위해필요하다. 10 장기능부전으로정맥영양의존도가높고정맥영양지원이장기화된다면담즙정체와같은대사적합병증이발생할수있으 20 Journal of Clinical Nutrition
며, 특히신생아는 1개월간의정맥영양공급으로도담즙정체가발생할수있다. 정맥영양관련간질환은단장증후군환자의주요사망원인이므로, 담즙정체와간손상으로의이행을방지해야하며, 이를위해서는가능한적극적으로경장영양을시도해야한다. 또한정맥영양으로인한담즙정체를예방하기위해서는정맥영양으로과도하게열량을공급하지않아야하고, 주기적정맥영양 (cyclic parenteral nutrition) 으로전환하여위장관호르몬분비를촉진하며, 철저한감염관리를해야한다. 11 2) 경장영양지원단장증후군아동에서경장영양의목표는영양자극으로장의적응도를향상시키고, 위장관사용을통해담즙정체를방지하며, 가능한정맥영양주입시간을줄여환아와보호자의삶의질을향상시키고, 궁극적으로는경장영양으로영양요구량에도달하여정맥영양을중단하는것이다. (1) 경장영양시작시기 : 최소경장영양 (trophic feeding) 의중요성은익히알려져있으며이는단장증후군소아에서도동일하다. 코크란리뷰에따르면장절제술후가능한빠른시기에경장영양을시작하는것이장적응을촉진하고재원기간을단축했다. 12 단장증후군으로정의되지는않았으나장절제술을시행한신생아에서수술 12시간후에모유를소량섭취하는것이가능했고, 수술후발생한장마비가소실된후경장영양을시작한대조군에비해영양요구량에도달하는기간과재원기간이유의적으로짧았다. 13 장절제술후 12 24시간이경과하면남아있는장의적응을높이기위해생리적으로장관내구조적기능적변화가시작되고이과정은길게는 1 2년후까지도진행된다. 14 하지만장절제술후 1년이경과한후에도남아있는장의적응도가낮다면그이후장기능의향상은크게기대하기어려우므로가능한장절제술후 1년이내에장적응도를높이기위한경장영양전략이중요하다. 15 특히연령이어릴수록장기능이성장할잠재성이높으므로, 장절제술을시행한영유아에서가능한조기에경장영양을도입해야한다. (2) 경장영양증량 : 최소경장영양을시작한후경장영양을증량하는시기와방법에대한연구적근거는부족하다. 주로임상적경험에의존하여각센터별로차이가있으나, 일반적으로는 3일정도의간격을두어증량하되신생아및영아는 1 ml/h/day 정도의양으로점진적으로증량하는것이권장됐다. 증량하여 3 일간관찰하는순응도의지표는구토, 변의양상, 변의양, 변의산도 (ph) 등이다. 구토는 1일 3회미만또는섭취량의 20% 미만일경우에, 변의양은 30 50 ml/kg/day 미만일경우에, 변의 ph는 5.5 이상일경우에증량하는것이바람직하며, 그렇지 않을경우에는섭취량을유지하거나감량했다. 16,17 경장영양공급량이증가되면정맥영양의감량을고려할수있는데, 단장증후군에서경장영양의흡수율은명확히알수없으므로증량된경장영양과동일열량으로정맥영양을감량하는것은바람직하지않다. 변의양, 탈수여부, 성장속도를관찰하여정맥영양공급량을조정한다. (3) 경장영양공급방법 : 단장증후군소아에서간헐적경장영양대비지속적경장영양의유용성에대해서는연구결과에명백한차이가없다. 하지만, 지속적경장영양은음식이천천히주입되기때문에삼투성설사를감소시키는이점이있으며, 장내영양소의잔류기간이길어져장에서흡수가증진되고결과적으로장기능을향상시킬수있다는것을근거로지속적경장영양의유용성을주장하는연구도있다. 16 지속적경장영양이단장증후군아동에서체중증가에이점이있었으며, 18 간헐적경장영양이지속적경장영양보다더생리적이긴하지만, 단장증후군아동에서는지속적경장영양이더수응도가높았다고도보고되었다. 19 하지만비위관또는비장관의삽입을외관상의이유로환자가거부하거나삽입한관이쉽게빠지는문제등이있기때문에위의결과와는달리실제로단장증후군아동에서경관영양을적극적으로적용하는데는어려움이따르기도한다. (4) 경장영양제제 : 건강한영아뿐만아니라단장증후군영아에서도가장좋은영양급원은모유이다. 모유에는뉴클레오타이드, 면역글로불린A 등이다량함유되어있어장면역기능향상에유용하며, 글루타민, 성장호르몬, 표피성장인자등이함유되어장적응을촉진시키는데도움이된다. 증례연구에따르면, 장절제술후모유를섭취한신생아에서분유를섭취한대조군에비해정맥영양기간이단축되었다. 20 단장증후군아동에서일반조제분유 (polymeric formula) 와가수분해분유 (semi-elemental or elemental formula) 간의유용성의차이는명백하지않다. 메타분석연구에따르면일반조제분유와가수분해분유에서흡수율의차이는없었다. 21 하지만단장증후군에서는장적응을위한기전으로장투과성이증가하여식품알레르기의위험이비교적높아지기때문에, 이론적근거에따라가수분해분유의사용을권장하였다. 22 일부에서는 12 24개월이상유아는우유, 콩등의알레르기가소실되므로유아용일반제제를사용할수있다고주장하기도했다. 한편으로는단장증후군영아에서아미노산제제분유가경장영양적응을높였다는증례연구도있다. 23 (5) 경구영양 : 단장증후군아동에서경구영양의시작시기와음식종류에대해서시행된임상연구는거의없다. 치료를위해금식기간이길어지고경구섭취의기회가제한됨에따라단장 Volume 6, Number 1, April 2014 21
Ji-Young Song and Hyun-Young Kim 증후군아동에서구강운동장애, 음식혐오, 섭식장애등이발생하기쉽다. 따라서경구섭취가금기인상태가아니라면, 빨고삼키는반사를촉진하기위해가능한이른시기에소량씩경구수유를시도하는것이필요하다. 단장증후군아동에서고형식의도입이늦춰질이론적근거는없으며, 일반적인영유아와마찬가지로고형식은교정월령 4 6개월경도입하고, 고형식의종류는개별환아의특성에따라영양사가조정한다. 16 (6) 열량영양소 : 열량영양소의구성에대해서는아직명확하게제시된바가없으나, 삼투성설사가유발되는것을우려하여당류를비롯한탄수화물섭취비율을높이지않도록권장된다. 성인이나청소년단장증후군에서는소화되지않은탄수화물에의해생성된단쇄지방산이대장에서대사되어중요한열량공급원이되기때문에대장의유무에따라식사지침에차이가있다. 하지만, 단장증후군이있는영아나어린아동은단쇄지방산이생성및대사되기에는장의통과속도가빠르기때문에탄수화물섭취로인한이점이낮다. 이와같은맥락에서단장증후군영유아에서고단백, 고지방음식섭취가고탄수화물음식보다장적응수응도가높았으며, 단장증후군영유아에게는탄수화물을 40% 이하로제공하도록권장하기도하였다. 24 중쇄지방산은장쇄지방산에비해체내흡수와대사가빠른장점이있으나, 장쇄지방산보다삼투압이높으며, 장쇄지방산의영양적자극효과를기대할수없는단점이있다. 대부분의가수분해제제에는소화흡수를돕기위해총지방중중쇄지방산이 5% 70% 정도함유되어있으며, 담즙정체및환아의개별적인순응도에따라장쇄지방산과중쇄지방산의비율을조정하도록한다. (7) 섬유소 : 단장증후군아동에서섬유소섭취에대한유용성평가의메타분석연구결과는없다. 몇가지증례연구에서는, 3 세단장증후군남아에서펙틴을식사에첨가했을때장통과시간이늦춰지고질소흡수가증가되었으며, 25 장절제술을시행한미숙아에서가수분해분유에펙틴을 1% 3% 첨가하여섭취했을때, 대사성산증이호전되고대변으로배설되는지방이 50% 감소되었다. 26 또한단장증후군영아에서완두콩추출물과고무당 (sugar gum) 을분유에첨가했을때장적응에효과적이었다고보고하였다. 27 단, 섬유소섭취가과다할경우아연, 철분, 마그네슘등무기질흡수가저해되므로이에대한주의가필요하며, 대장이적절한기능을할수있는단장증후군아동에서시도해봄직하다. 결론 소아의단장증후군은영양소의장내흡수면적이감소되어 있어탈수, 전해질이상, 영양소흡수불량등을초래하는질환으로소아의생존및성장을위해적절한영양지원이필수적이다. 영양지원에있어서는개별환자들의상태를파악하여단장증후군으로인한합병증을예방하고장적응도를높일수있도록하여야한다. REFERENCES 1. Touloukian RJ, Smith GJ. Normal intestinal length in preterm infants. J Pediatr Surg 1983;18(6):720-3. 2. Hong CH, Pediatrics. 8th ed. Seoul:Daehan;2004:567. 3. Bhatia J, Gates A, Parish A. Medical management of short gut syndrome. J Perinatol 2010;30(Suppl):S2-5. 4. Bishop WP. Polyps and tumors of the intestine. In: Bishop WP, ed. Pediatric practice gastroenterology. New York:McGraw-Hill; 2010:295. 5. Rhoads JM, Plunkett E, Galanko J, Lichtman S, Taylor L, Maynor A, et al. Serum citrulline levels correlate with enteral tolerance and bowel length in infants with short bowel syndrome. J Pediatr 2005;146(4):542-7. 6. Garcia VF, Templeton JM, Eichelberger MR, Koop CE, Vinograd I. Colon interposition for the short bowel syndrome. J Pediatr Surg 1981;16(6):994-5. 7. O neill JA, Rowe MI, Grosfeld JL, Fonkalsrud EW, Coran AG. Pediatric surgery. 5th ed. St. Louis:Mosby;1998:1223-6. 8. Brunicardi CF. Schwartz s principles of surgery. 9th ed. New York, NY:McGrawl_Hill;2011. 9. Magee JC, Krishnan SM, Benfield MR, Hsu DT, Shneider BL. Pediatric transplantation in the United States, 1997-2006. Am J Transplant 2008;8(4 Pt 2):935-45. 10. Seoul National University Children's Hospital Nutirtional Support Team. Nutritional support for children. 1st ed. Seoul:Daehan; 2012:150-9. 11. Sondheimer JM, Asturias E, Cadnapaphornchai M. Infection and cholestasis in neonates with intestinal resection and long-term parenteral nutrition. J Pediatr Gastroenterol Nutr 1998;27(2):131-7. 12. Tyson JE, Kennedy KA. Minimal enteral nutrition for promoting feeding tolerance and preventing morbidity in parenterally fed infants. Cochrane Database Syst Rev 2000;(2):CD000504. 13. Ekingen G, Ceran C, Guvenc BH, Tuzlaci A, Kahraman H. Early enteral feeding in newborn surgical patients. Nutrition 2005; 21(2):142-6. 14. American Gastroenterological Association. American Gastroenterological Association medical position statement: short bowel syndrome and intestinal transplantation. Gastroenterology 2003;124(4):1105-10. 15. Quirós-Tejeira RE, Ament ME, Reyen L, Herzog F, Merjanian M, Olivares-Serrano N, et al. Long-term parenteral nutritional support and intestinal adaptation in children with short bowel 22 Journal of Clinical Nutrition
syndrome: a 25-year experience. J Pediatr 2004;145(2):157-63. 16. Vanderhoof JA, Young RJ. Enteral and parenteral nutrition in the care of patients with short-bowel syndrome. Best Pract Res Clin Gastroenterol 2003;17(6):997-1015. 17. Wessel JJ, Kocoshis SA. Nutritional management of infants with short bowel syndrome. Semin Perinatol 2007;31(2):104-11. 18. Parker P, Stroop S, Greene H. A controlled comparison of continuous versus intermittent feeding in the treatment of infants with intestinal disease. J Pediatr 1981;99(3):360-4. 19. Goulet O, Sauvat F. Short bowel syndrome and intestinal transplantation in children. Curr Opin Clin Nutr Metab Care 2006;9(3):304-13. 20. Andorsky DJ, Lund DP, Lillehei CW, Jaksic T, Dicanzio J, Richardson DS, et al. Nutritional and other postoperative management of neonates with short bowel syndrome correlates with clinical outcomes. J Pediatr 2001;139(1):27-33. 21. Ksiazyk J, Piena M, Kierkus J, Lyszkowska M. Hydrolyzed versus nonhydrolyzed protein diet in short bowel syndrome in children. J Pediatr Gastroenterol Nutr 2002;35(5):615-8. 22. Vanderhoof JA, Young RJ. Hydrolyzed versus nonhydrolyzed protein diet in short bowel syndrome in children. J Pediatr Gastroenterol Nutr 2004;38(1):107. 23. Bines J, Francis D, Hill D. Reducing parenteral requirement in children with short bowel syndrome: impact of an amino acid-based complete infant formula. J Pediatr Gastroenterol Nutr 1998;26(2):123-8. 24. Warner BW, Vanderhoof JA, Reyes JD. What's new in the management of short gut syndrome in children. J Am Coll Surg 2000;190(6):725-36. 25. Finkel Y, Brown G, Smith HL, Buchanan E, Booth IW. The effects of a pectin-supplemented elemental diet in a boy with short gut syndrome. Acta Paediatr Scand 1990;79(10):983-6. 26. Hawkins R, Henry B, Gottschalk ME. Pectin supplemented Enteral feedings in the treatment of short bowel syndrome in two infants. J Am Diet Assoc 1995;95(9):A28. 27. Drenckpohl D, Hocker J, Shareef M, Vegunta R, Colgan C. Adding dietary green beans resolves the diarrhea associated with bowel surgery in neonates: a case study. Nutr Clin Pract 2005; 20(6):674-7. Volume 6, Number 1, April 2014 23