Small Bowel Obstruction Flashcards
MCC of small bowel obstruction
most common causes are adhesions followed by tumors and hernias. Other causes include strictures, intussuseption, volvulus, Chrohn’s disease, and gallstones.
How does a SBO begin
Small bowel obstruction begins when the normal luminal flow of intestinal contents is interrupted and the small intestine proximal to the obstruction dilates. Secretions are prevented from passing distally. As time progresses, the distension leads to nausea and vomiting and inability to take oral intake.
What is the difference between partial and complete SBO and how does treatment differ?
Partial obstruction is when gas or liquid stool can pass through the point of narrowing and complete obstruction is when no substance can pass.
- Surgery usually for complete, conservative treatment for partial.
What is the most severe complication of a SBO?
Strangulation - is a surgical emergency. Occurs when bowel wall edema compromises perfusion to the intestine and necrosis ensues. Can lead to perforation, peritonitis and death.
Common presentation of SBO
- Abdominal pain, abdominal distension, vomiting, and inability to pass flatus. In proximal obstruction - nausea and vomiting more prevalent.
- Pain crampy and intermittent with a simple obstruction.
- More severe pain, it may indicate the development of strangulation or ischemia.
- May complain of diarrhea early in the course of bowel obstruction, with inability to pass flatus and obstipation occurring after the distal portion of the bowel has emptied (up to 12-24 hours).
What history is important to get the most?
History of abdominal surgery. Indicates adhesions as most possible cause. Also ask about Crohn’s.
What if the patient has no history of abdominal surgery?
“de novo small bowel obstruction”. These are caused by tumor until proven otherwise and usually require a surgical intervention.
PE findings
- Abdominal distension (more prevalent in distal obstructions), hyperactive bowel sounds (early), or hypoactive bowel sounds (late).
- Fever, tachycardia and peritoneal signs may be associated with strangulation.
- Look for inguinal hernias - genitourinary exam. Rectal examination - gross blood or hemoccult positive stool suggests strangulation or malignancy.
What imaging do you need?
- Upright CXR - Free air - perforation
- Upright abdominal XR - air fluid levels
- Supine abdominal XR - dilated loops of bowel
Note: Absence of air in the colon or rectum suggests a complete obstruction while the presence of air in the colon suggests a partial obstruction
How can you confirm?
- Small bowel follow through (used to be gold standard)
- CT
CT findings
- Obstruction is present if the small-bowel loop is greater than 2.5 cm in diameter dilated proximal to a distinct transition zone of collapsed bowel less than 1 cm in diameter
- Bowel wall thickening, pneumatosis, and portal venous gas all suggest strangulation.
- CT can also differentiate between the etiologies of SBO, that is, extrinsic causes such as adhesions and hernia from intrinsic causes such as neoplasms or Crohn’s disease.
- Use Oral and IV contrast
- Can also help if you are worried about other etiologies
Treatment of SBO
resuscitation and electrolyte replacement
identifying the severity and cause of the obstruction
GI decompression
symptomatic treatment
determining whether or not surgical intervention is indicated
Nonoperative management
Non-operative management consists of GI decompression with a nasogastric tube, intravenous fluid hydration, bowel rest, and symptomatic treatment.
When to do operative management
If the patient’s exam or CT scan suggests strangulation (peritonitis, thickened bowel wall, etc) then operative intervention should ensue. If there are no signs of impending strangulation, then non-operative management may be appropriate.
