MRCS Knowledge: Small Bowel Obstruction
07/10/14 09:17 Filed in: MRCS Knowledge
MRCS Part B Knowledge: Small Bowel Obstruction
Today’s MRCS Knowledge short notes are on Small Bowel Obstruction.
Background
Mechanical or functional obstruction of the small bowel, preventing the normal transit of the products of digestion
Aetiology
Causes of SBO:
- Adhesions: commonest cause due to either congenital bands or adhesions after previous abdominal surgery
- Hernias
- Tumours (especially of the caecum)
- Food bolus
- Small bowel volvulus around the mesentery
Signs and Symptoms
- Distended abdomen
- ‘Tinkling’ bowel sounds
- Palpable masses or hernias
- Empty rectum on PR
- Early vomiting
- Central/upper abdo pain that is colicky in nature
- Abdo distension (less than in large bowel obstruction)
- No flatus
- Constipation
Investigations
- Bloods: FBC, U&Es
- Erect CXR: looking for air under diaphragm indicating perforation
- AXR: central, dilated loops of small bowel, >2.5cm (distinguished by valvulae conniventes which completely cross bowel diameter)
- CT Abdo: identify level and cause of obstruction
- Gastrograffin follow-through: identify level and cause of obstruction
Management
Immediate: NBM, nasogastric tube and IV fluids ‘drip and suck’, urinary catheter to monitor fluid balance
Failure of immediate management or signs of strangulation requires surgical intervention to relieve obstruction +/- bowel resection
Prognosis
Complications: Perforation, strangulation, severe dehydration, death
Further Info:
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