Bowel obstruction pathophysiology: Difference between revisions
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==Associated Conditions== | ==Associated Conditions== | ||
*Conditions associated with extrinsic bowel obstruction include: | *Conditions associated with extrinsic bowel obstruction include:<ref name="pmid10971435">{{cite journal |vauthors=Miller G, Boman J, Shrier I, Gordon PH |title=Natural history of patients with adhesive small bowel obstruction |journal=Br J Surg |volume=87 |issue=9 |pages=1240–7 |year=2000 |pmid=10971435 |doi=10.1046/j.1365-2168.2000.01530.x |url=}}</ref><ref name="pmid7573729">{{cite journal |vauthors=Barkan H, Webster S, Ozeran S |title=Factors predicting the recurrence of adhesive small-bowel obstruction |journal=Am. J. Surg. |volume=170 |issue=4 |pages=361–5 |year=1995 |pmid=7573729 |doi= |url=}}</ref><ref name="pmid19756860">{{cite journal |vauthors=Butt MU, Velmahos GC, Zacharias N, Alam HB, de Moya M, King DR |title=Adhesional small bowel obstruction in the absence of previous operations: management and outcomes |journal=World J Surg |volume=33 |issue=11 |pages=2368–71 |year=2009 |pmid=19756860 |doi=10.1007/s00268-009-0200-6 |url=}}</ref><ref name="pmid24565365">{{cite journal |vauthors=Beardsley C, Furtado R, Mosse C, Gananadha S, Fergusson J, Jeans P, Beenen E |title=Small bowel obstruction in the virgin abdomen: the need for a mandatory laparotomy explored |journal=Am. J. Surg. |volume=208 |issue=2 |pages=243–8 |year=2014 |pmid=24565365 |doi=10.1016/j.amjsurg.2013.09.034 |url=}}</ref> | ||
**Adhesions | **Adhesions | ||
**Hernia | **Hernia | ||
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**Volvulus | **Volvulus | ||
**Hematoma | **Hematoma | ||
==Gross Pathology== | ==Gross Pathology== | ||
Revision as of 19:05, 15 January 2018
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Hadeel Maksoud M.D.[2]
Overview
It is thought that bowel obstruction may occurs functionally as a result of abnormal anatomy or mechanically, which may occur acutely or chronically. An obstruction may occur extrinsically, intrinsically or intraluminally including tumors, strictures and foreign bodies. Excessive bowel distention can lead to ischemia, necrosis and perforation.
Pathophysiology
Pathogenesis
- Normally, the small intestine functions to pass gastrointestinal contents for absorption. The large surface area provided by the villi, plicae circularis and valvulae conniventes allow for this exchange to happens.[1][2][3]
- In addition, the small bowel is free of microbes, in comparison to the large bowel that houses commensal flora that facilitate digestion and vitamin synthesis, namely vitamin K.
- Continuous transit throughout the bowel is important to prevent bowel dilatation, ischemia and necrosis.
- Obstruction of the bowel can occur functionally (due to abnormal anatomy) or mechanically, which can be acute or chronic.
- Obstructions can be extrinsic, intrinsic or intraluminal obstruction.
- Extrinsic obstructions can happen as the result of a tumor, post-operative adhesions or hernias.
- Intrinsic obstructions can happen as a result of a tumor, stenosis or hematoma.
- Intraluminal obstructions are sometimes referred to intramural obstructions and include, foreign bodies, intussusception and gallstones.
- However an obstruction occurs, proximal to the blockage there will be a dilated segment, whilst distal to the obstruction the segment of bowel will collapse as the contents cannot pass.
- Bowel distention occurs as air that is swallowed and gases produced by the commensal flora begins to accumulate.
- Eventually, the bowel wall becomes edematous and fluid gathers inside the lumen of the bowel. This disrupts the absorptive properties of the gut.
- Some fluid may be lost to the peritoneal cavity, moreover, the proximal obstruction causes severe emesis which will lead to further loss of fluid that contains several electrolytes. This process may result in metabolic alkalosis and hypovolemia.
- The obstruction also causes the normally sterile proximal bowel to become overgrown with bacteria and vomitus may contain feces.
- When a massive dilation of the bowel occurs, the vessels that perfuse the walls of the bowel become compressed and will not be able to supply the bowel loop adequately, which leads to ischemia.
- If ischemia is not reversed within a timely manner, then necrosis, volvulus and perforation may ensue.
Genetics
The development of congenital bowel obstruction is the result of multiple genetic mutations:[4][5][6][7]
- Chromosome 21 trisomy can lead to imperforate anus and duodenal atresias in 50% of babies with down syndrome.
- Chromosome 7 mutation locus leads to cystic fibrosis that predisposes to a thickened meconium which may lead to an intraluminal obstruction of the terminal ileum and microcolon.
- Hirschsprung disease is associated with several gene mutations:
- The RET proto-oncogene located on chromosome 10q11.21 that interacts with the EDNRB protein located on chromosome 13.
- Mutations in the RET and 3p21, 9q31, and 19q12 genes leads to failure of migration of the enteric neural crest cells.
- Hirschsprung syndromes are associated with PHOX2B homeobox gene mutations.
- The following protein mutations may also lead to Hirschsprung disease:
- Chromosome 5 - GDNF protein
- Chromosome 20 - EDN3 protein
- Chromosome 22 - SOX10 protein
- Chromosom 1 - ECE1 protein
- Chromosome 19 - NTN protein
- Chromosome 2 - SIP1 protein
Associated Conditions
- Conditions associated with extrinsic bowel obstruction include:[8][9][10][11]
- Adhesions
- Hernia
- Volvulus
- Endometriosis
- Conditions associated with intrinsic bowel obstruction include:
- Large and small bowel cancers
- Cystic fibrosis
- Hirschsprung disease
- Down's syndrome
- Strictures:
- Anatomical
- Inflammatory
- Ischemic
- Radiation
- Conditions associated with intraluminal bowel obstruction include:
- Gastrointestinal foreign body
- Intussusception
- Gallstones
- Constipation
- Bezoar
- Volvulus
- Hematoma
Gross Pathology
- On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
Microscopic Pathology
- On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
References
- ↑ Wright HK, O'Brien JJ, Tilson MD (1971). "Water absorption in experimental closed segment obstruction of the ileum in man". Am. J. Surg. 121 (1): 96–9. PMID 5540839.
- ↑ Noer RJ, Derr JW, Johnston CG (1949). "The Circulation of the Small Intestine: An Evaluation of its Revascularizing Potential". Ann. Surg. 130 (4): 608–21. PMC 1616446. PMID 17859455.
- ↑ Markogiannakis H, Messaris E, Dardamanis D, Pararas N, Tzertzemelis D, Giannopoulos P, Larentzakis A, Lagoudianakis E, Manouras A, Bramis I (2007). "Acute mechanical bowel obstruction: clinical presentation, etiology, management and outcome". World J. Gastroenterol. 13 (3): 432–7. PMC 4065900. PMID 17230614.
- ↑ Mitul AR (2016). "Congenital Neonatal Intestinal Obstruction". J Neonatal Surg. 5 (4): 41. doi:10.21699/jns.v5i4.472. PMC 5117264. PMID 27896149.
- ↑ Huis M, Stulhofer M, Szerda F, Vukić T, Bubnjar J (2006). "[Obstruction icterus--our experience]". Acta Med Croatica. 60 (1): 71–6. PMID 16802577.
- ↑ BODIAN M, WHITE LL, CARTER CO, LOUW JH (1952). "Congenital duodenal obstruction and mongolism". Br Med J. 1 (4749): 77–9. PMC 2022519. PMID 14896034.
- ↑ Dalla Vecchia LK, Grosfeld JL, West KW, Rescorla FJ, Scherer LR, Engum SA (1998). "Intestinal atresia and stenosis: a 25-year experience with 277 cases". Arch Surg. 133 (5): 490–6, discussion 496–7. PMID 9605910.
- ↑ Miller G, Boman J, Shrier I, Gordon PH (2000). "Natural history of patients with adhesive small bowel obstruction". Br J Surg. 87 (9): 1240–7. doi:10.1046/j.1365-2168.2000.01530.x. PMID 10971435.
- ↑ Barkan H, Webster S, Ozeran S (1995). "Factors predicting the recurrence of adhesive small-bowel obstruction". Am. J. Surg. 170 (4): 361–5. PMID 7573729.
- ↑ Butt MU, Velmahos GC, Zacharias N, Alam HB, de Moya M, King DR (2009). "Adhesional small bowel obstruction in the absence of previous operations: management and outcomes". World J Surg. 33 (11): 2368–71. doi:10.1007/s00268-009-0200-6. PMID 19756860.
- ↑ Beardsley C, Furtado R, Mosse C, Gananadha S, Fergusson J, Jeans P, Beenen E (2014). "Small bowel obstruction in the virgin abdomen: the need for a mandatory laparotomy explored". Am. J. Surg. 208 (2): 243–8. doi:10.1016/j.amjsurg.2013.09.034. PMID 24565365.