11. Small and large bowel obstruction

Question 1

How common is it?

Answer 1

Makes up 15% of acute abdomen presentations

Question 2

What causes are there?

Answer 2

Small bowel - adhesions, hernias

Large bowel - malignancy, constipation, diverticular stricture, sigmoid / caecal volvulus

Question 3

What risk factors are there?

Answer 3

Previous surgery, malignancy, radiation, bowel pathology (as in causes), increasing age

Question 4

How does it present?

Answer 4

Abdo pain - colicky, cramp
Vomiting - early in proximal, later in distal obstructions
Abdo distension
Absolute constipation - early in distal, late in proximal

Question 5

What signs may the patient have on examination?

Answer 5

Signs of underlying cause eg surgical scars, cachexia, hernia
Focal / rebound tenderness, guarding
Tinkling bowel sounds, tympanic on percussion

Question 6

What other conditions might present similarly?

Answer 6

Pseudo-obstruction, paralytic ileus, toxic megacolon, constipation

Question 7

How would you investigate this patient?

Answer 7

Urgent bloods inc FBC, U+Es, G&S
VBG (check lactate, if >2 could be a sign of ischaemia)
Abdominal X-ray - bowel loops
CXR - air below diaphragm if perforated
CT

Question 8

What treatments are there?

Answer 8

Depends on cause
Urgent fluid resus
Urgent surgery if ischaemic / closed loop bowel
NG tube, analgesia

Question 9

What complications are there?

Answer 9

Bowel ischaemia
Bowel perforation –> peritonitis
Dehydration, renal impairment