Bowel Obstruction.pptx

Bowel Obstruction

Small Bowel Obstruction

Emergency surgery, 2010

Pathophysiology • Initially, bowel dilation occurs secondary . • Approximately, 8–9 L/day of digestive juices are secreted and reabsorbed within the gastrointestinal tract; any interference to this process leads to rapid intraluminal stasis  bacterial overgrowth,with resulting fermentation of undigested bowel contents  accumulation of gas.

• Fermentation creates an osmotic gradient resulting in movement of fluid and electrolytes into the lumen. • This can equate to several litres of fluid sequestered within the bowel, termed ‘third space’ losses from the intravascular space.

• Vomiting accentuates fluid and electrolyte losses, and patients are prone to developing hypokalaemia as the obstruction progresses. • Urine output falls as the hypovolaemia

• Pressure within the bowel wall low-pressure venous return  venous congestion develops. • This creates a vicious cycle of further reductions in bowel wall perfusion, with further accompanying fluid losses. • This eventually culminates in ischaemia,infarction and intestinal perforation, with failure of the mucosal barrier also allowing bacterial translocation to occur.

Strangulated obstruction is a term used to denote bowel with a compromised blood supply, either through venous congestion or arterial occlusion. Closed loop obstruction is a special case where both the proximal and distal points of a bowel segment are obstructed, Emergency Surgery, 2010

Symptoms • pain, distension, constipation,vomiting and dehydration. • Colicky pain becoming more localised and constant, or the presence of signs indicating peritonism, both suggest simple obstruction may have progressed to infarction or perforation.

• As the obstruction progresses and flaccidity develops peristalsis ceases and the colicky pain becomes a less predominant feature. • It is usually absent in paralytic ileus.

‘Don’t let the sun set and rise on intestinal obstruction’

Plain Abdominal Photo

Emergency Surgery, 2010

Management

Emerrgency Surgery,2010

Large Bowel Obstruction • mechanical (colorectal carcinoma[CRC], diverticulitis, volvulus, faecal impaction, inflammatory bowel disease [IBD], anastomotic stricture and other pelvic malignancies), and non-mechanical causes (acute colonic pseudo-obstruction). • Furthermore, obstruction can be complete or partial

• Abdominal malignancy : progressive complaints of constipation, decreasing stool calibre, haematochezia, vague abdominal pain, weight loss and general malaise. • Diverticulitis :recurrent, localised (usually left lower quadrant) pain radiating to the groin or perineum with defecation, and accompanied by fevers and constipation. • Colonic volvulus may not be associated with specific signs and symptoms aside from abdominal pain and distention most pronounced in the upper quadrants of the abdomen.