Bowel Obstruction

Question 1

What are the two classifications of bowel obstruction?

Answer 1

Paralytic/Pseudo obstruction

Mechanical

Question 2

what are the classifications of mechanical bowel obstruction?

Answer 2

Speed on Onset: acute, chronic, acute on chronic
Site: high or low
Nature: simple versus strangulating
Aetiology
Causes in the lumen, wall or outside the wall

Question 3

what are causes of small bowel obstruction?

Answer 3

ADHESIONS + HERNIAE
Also: Tumours, Crohn’s, Volvulus, Gallstone ileus, Intersusception, Radiation strictures, Ischaemia, TB, Trichobezoar, Phytobezoar, Atresia, Paralytic ileus

Question 4

what are the causes of large bowel obstruction?

Answer 4

Colon cancer
Benign strictures – e.g. diverticular disease, IBD, ischaemic bowel, radiation damage
Sigmoid volvulus
Intussusception
Herniae 
Psuedo-obstruction

Question 5

what are the causes of pseudo obstruction bowel obstruction?

Answer 5

myopathy/neuropathy, Hirschsprung

Question 6

what are the causes of neonatal bowel obstruction?

Answer 6

congenital atresia and stenosis, imperforate anus, volvulus neonatorum, Hirschsprungs disease and meconium ileus

Question 7

what are the causes of bowel obstruction in infants?

Answer 7

intussusception, Hirschsprungs disease, strangulated hernia and obstruction fue to Meckel’s diverticulum

Question 8

what are the causes of bowel obstruction in young adults/middle aged people?

Answer 8

strangulated hernia, adhesions and bands, Crohns

Question 9

what are the causes of bowel obstruction in the elderly?

Answer 9

strangulated hernia, carcinoma of the colon, colonic diverticulitis impacted faeces

Question 10

what are the clinical features of simple bowel obstruction?

Answer 10

o Nausea/Vomiting – early in high obstruction, late or absent in chronic or in low
o Late stages vomit becomes faecal
o Colicky pain – periumbilical in SBO, lower down in LBO
o Absolute Constipation
o Diarrhoea
o Distension - LBO
o Rectal bleeding - LBO

Question 11

what are the clinical features of strangulating bowel obstruction?

Answer 11

o Fever
o Tachycardia
o Change of pain from colicky to continuous
o Peritonism
o Bowel sounds absent or reduced in SBO, loud in LBO
o Leucocytosis
o Raised CRP

Question 12

what investigations can be done for bowel obstruction?

Answer 12

Abdo (and chest?) x-ray (erect and supine)
CT combined with oral water-soluble contrast
Blood tests
Laparotomy

Question 13

what features will be present in the AXR of bowel obstruction?

Answer 13

distended bowel (>5cm – the normal size of the small bowel is 2.5cm)

Question 14

how do you differentiate small bowel from large bowel on AXR?

Answer 14

o Small bowel loops are the width of the lumen (lines)
o Large bowel loops are not the complete width of the lumen (lines)
Also the width

Question 15

what features may be seen in the blood tests of someone with bowel obstruction?

Answer 15

o Full blood count (anaemia? – may be present in caecal carcinoma)
o U+E’s – Fluid and electrolyte disturbance (particularly with potassium) may be present
o Amylase
o Likely raised CRP

Question 16

what is the management of bowel obstruction

Answer 16

Drip and Suck = Gastric aspiration via nasogastric suction + IV fluid replacement
Antibiotics – if intestinal strangulation
Surgery

Question 17

in bowel obstructions, what features indicate non-viable tissue?

Answer 17

Loss of peristalsis
Loss of normal sheen
Colour (green or black is non-viable, purple bowel may still recover)
Loss of arterial pulsation

Question 18

what surgical process occurs in SBO?

Answer 18

resected and primary anastomosis

Question 19

what surgical process occurs in LBO?

Answer 19

 Resection of obstructing lesion with a primary ileocolic anastomosis in the case of obstructing lesions proximal to splenic flexure

Question 20

when is surgical management not used in bowel obstruction?

Answer 20

If adhesions are the cause

Question 21

what are the complications of bowel obstruction?

Answer 21

• Bowel ischaemia
• Perforation
• Sepsis