Small bowel obstruction

Common causes of SBO in adults include:

• Adhesions from previous intra-abdominal surgery or previous intra-abdominal infections

• Acute incarcerated hernia including inguinal, femoral, ventral, incisional, umbilical, and parastomal hernias

• Crohn disease

• Intestinal malignancy.

Common causes of SBO in children include:

• Intussusception

• Intestinal atresia

• Volvulus.

Rare causes include radiation enteritis, intra-abdominal abscess (from perforated appendicitis/diverticulitis), gallstone ileus, foreign body, and intestinal bezoar.

SBO represents an interruption in the patency of the gastrointestinal tract. The proximal dilation of the intestine, together with peristalsis, leads to abdominal cramping (colic), which can become severe. The abdominal pain may also be accompanied by vomiting, while the distal interruption of fecal flow leads to absolute constipation. In acute cases, there can be hyperperistalsis distal to the obstruction, leading to the finding of diarrhea. Obstructed bowel cancer, over time, prevents appropriate venous drainage with the possible result of decreased arterial perfusion. Untreated patients could develop progressive intestinal ischemia, necrosis, and perforation.

According to the nature of the obstruction

Partial (incomplete) bowel obstruction

• Blockage of the intestine is not complete, resulting in partial passage of flatus and occasionally stool.

Complete bowel obstruction

• Blockage of the intestine completely obstructs the lumen of the intestine, resulting in failure to pass flatus and stool. Complete bowel obstruction is associated with a higher requirement for bowel resection than partial obstruction, and was previously considered an indication for operative management.[1]Maung AA, Johnson DC, Piper GL, et al; Eastern Association for the Surgery of Trauma. Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg. 2012 Nov;73(5 suppl 4):S362-9. https://journals.lww.com/jtrauma/Fulltext/2012/11004/Evaluation_and_management_of_small_bowel.14.aspx http://www.ncbi.nlm.nih.gov/pubmed/23114494?tool=bestpractice.com  However, evidence has shown that a proportion of patients (41% to 73%) may have resolution of the obstruction with nonoperative therapy.[1]Maung AA, Johnson DC, Piper GL, et al; Eastern Association for the Surgery of Trauma. Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg. 2012 Nov;73(5 suppl 4):S362-9. https://journals.lww.com/jtrauma/Fulltext/2012/11004/Evaluation_and_management_of_small_bowel.14.aspx http://www.ncbi.nlm.nih.gov/pubmed/23114494?tool=bestpractice.com ​ 

Simple bowel obstruction

• Intestinal blockage in the absence of intestinal ischemia/gangrene and/or perforation or peritonitis; may respond to nonoperative therapy.

Complicated bowel obstruction

• Surgical emergency in which the obstruction has progressed to intestinal ischemia/gangrene and/or perforation. Peritonitis is usually present. This is a life-threatening situation that requires urgent resuscitation and surgical intervention.