Clinical features of small bowel obstruction

Symptoms of small bowel obstruction include:

• abdominal pain, colicky, i.e. returns to normal periodically. Felt in mid-abdomen. Need to know site, radiation, duration and relieving factors.
• no flatus; constipation is present
• distention, early in the course of the illness if the obstruction is high
• vomiting, again earlier in the course if the obstruction is relatively proximal in the bowel

Signs of obstruction include:

• general appearance: dehydration due to loss of fluid from ECF when vomiting. The gastrointestinal tract secretes 6 litres of fluid per day and during obstruction, this tends to be sequestered. Hypovolaemia may result in hypotension and tachycardia.
• inspection and palpation may reveal scars, distension, peristalsis, hernias, but no tenderness. If the blood supply is cut off then there can be congestion, ischaemia, necrosis/gangrene and perforation; tenderness develops.
• auscultation: hyperactive - borborygmus - or ileus
• rectal examination: may be empty after 24 to 48 hours of symptoms