GI: Intestinal Obstruction

Question 1

Suggest causes for SBO.

Answer 1

1. adhesions from prev. surgery (75%)
2. hernias
3. Meckel’s diverticulum
4. malignancy - caecal tumour
5. gallstone ileus
6. paralytic ileus (common post-op)

Question 2

Suggest causes for LBO.

Answer 2

1. colorectal adenocarcinoma, esp. sigmoid (most common cause)
2. stricutures - IBD, diverticulitis
3. hernias - femoral/inguinal
4. faecal impaction (common in elderly)
5. sigmoid volvulus (5%)

Question 3

Describe the presentation of SBO and LBO.

Answer 3

Symptoms:

• abdominal pain (diffuse, central, colicky)
• nausea and vomiting (early in SBO, late in LBO) may be faeculent in LBO due to reverse peristalsis
• absolute constipation (late in SBO, early in LBO)

Signs:

• abdominal distension
• hyper-resonant percussion
• tinkling bowel sounds
• peritonism and sepsis

Question 4

Which investigations should be performed in a Pt with suspected obstruction?

Answer 4

1. Observations
   - fluid charts: monitor intake and output, as IV infusion almost certainly required, NG tube may be used and oliguria is important sign of early dehydration
2. Bloods
   - FBC
   - CRP
   - UandE: hypokalaemia and high urea may be present
   - creatinine
   - group and save
   - venous blood gas: evaluate signs of ischaemia (high lactate) and metabolic derangement (secondary to dehydration/excessive vomiting)
3. Imaging
   - CT abdo - gold standard
   - AXR - sensitivity 50-66% - proximal small bowel obstruction may be overlooked if no gas in small bowel.

Question 5

Describe the management of uncomplicated obstruction.

Answer 5

‘drip and suck’

1. fluid resuscitation and electrolyte replacement
2. intestinal decompression via NG tube
3. bowel rest

Endoscopy can also be used for dilation of strictures or placement of self-expandable metal stents to restore luminal flow.

Question 6

Describe the management of complicated obstruction.

Answer 6

When obstruction results in ischaemia, perforation or peritonitis, emergency surgery is required. May involve laparotomy, bowel resection, stoma, etc.

Question 7

Name 3 complications of bowel obstruction.`

Answer 7

1. perforation… peritonitis
2. bowel ischaemia… peritonitis
3. fluid and electrolyte imbalance, hypovolaemia and septicaemia may all contribute to circulatory collapse and AKI