Small bowel obstruction

Question 1

What are the types of small bowel obstructions

Answer 1

Dynamic: Mechanical obstruction
- Simple: lumen only
- Complicated: Strangulated -> compromised blood supply

Adynamic: Non-mechanical obstruction
- No obstruction to passage of bowel contents

Question 2

What are the causes of adynamic obstruction

Answer 2

Peritonitis
Mesenteric (vascular) occlusion
Pelvic fracture
Retroperitoneal haematoma
Metabolic Disorder:
- DKA
- Hyponatraemia
- Hypokalaemia
- Uraemia

Question 3

What are the causes of dymanic obstruction

Answer 3

Adhesions - tough fibrous connective tissue forming constricting bands
Hernias
Inturesusseption
Carcinomatosis
Bezoars
Annular pancreas
Gall stone ileus
Volvulus

Question 4

What are the clinical features of small bowel obstruction

Answer 4

Pain
Distention
Vomiting
Constipation/ obstipation
Increased Bowel sounds
X-ray features

Tenderness
Temperature
- these symptoms are indicative of complicated small bowel obstruction: bowel might be ischaemic

Question 5

What is the management of small bowel obstruction

Answer 5

Nasogastric suction
IV fluids
Correction of electrolytes
Monitoring
Removal of cause
Surgery

Question 6

What are the red flags that should be monitored in the management of small bowel obstruction

Answer 6

Dehydration
Pain & Tenderness
Electrolytes Derangement
Blood gas- (pH & HCO3)
Elevated WBC
Free intra-peritoneal gas

Question 7

What are the indications for surgery in small bowel obstruction

Answer 7

Hernia
Peritonitis
Evidence of strangulation/ Ischemia
Metabolic derangements
Non resolution
Cancer

Question 8

Explain the normal motility electrical activity in terms of:
- Slow waves
- Spike discharges
- Small bowel contraction types

Answer 8

Slow waves:
- Pacesetter cells

Spike discharges:
- Contractile potentials

Small bowel contraction types:
- Ring contraction
- Peristaltic contractions

Question 9

What is the pathophysiology of small bowel obstruction

Answer 9

Ingested fluid and food, digestive secretions, and gas accumulate above the obstruction. The proximal bowel distends leading to reactive hyperperistalsis and the distal segment collapses. The normal secretory and absorptive functions of the mucosa are depressed, and the bowel wall becomes edematous and congested