Intestinal Obstruction

Question 1

What are the symptoms of SBO?

Answer 1

Abdominal Pain
Abdominal distension
N&V- early sign
Absolute constipation- later sign

Question 2

What are the signs of intestinal obstruction?

Answer 2

Signs of dehydration
Abdominal distension
Hyper-resonant bowel if distended
Bowel mass
Peritonism
Tinkling bowel signs- more common in SBO

Question 3

What are the common causes of small bowel obstruction?

Answer 3

Adhesions
Hernias
Intussusception (children)
Crohns

Question 4

What are the common causes of large bowel obstruction?

Answer 4

Colon carcinoma
Constipation
Diverticular strictures
Vovlulus
-sigmoid
-caecal

Question 5

What are the rarer causes of bowel obstruction?

Answer 5

Crohn's stricture
Gallstone ileus
Intussusception
TB
Foreign body

Question 6

How can large and small bowel obstruction be distinguished clinically?

Answer 6

Small bowel
-vomiting occurs earlier
-less distension
-pain higher up
Large bowel
-pain is more constant

Question 7

What are the large and small bowel obstruction differences seen on an AXR?

Answer 7

Small bowel

• distension more central
• > 3cm
• Valvular connivente present (cross entire width of intestine)
• empty colon

Large bowel

• distension more peripheral
• > 6cm
• haustra not crossing entire width of intestine

Question 8

How can ileus and mechanical obstructions be distinguished?

Answer 8

Ileus- temporary loss of peristalsis leading to constipation

No bowel sounds present

Question 9

What are the complications of intestinal obstruction?

Answer 9

Fluid/electrolyte shifts
Vascular compromise
Sepsis

Strangulation
Perforation
Necrosis

Question 10

What causes fluid shifts in bowel obstruction?

Answer 10

Internal loss (water pooling in bowel 1.5-3l)
External loss (vomiting, diarrhoea, fistulae)

Question 11

What causes the electrolyte shifts in bowel obstruction?

Answer 11

Loss of water causes electrolyte disturbances

• hyponatremia
• hypokalaemia
• metabolic alkalosis

Question 12

What causes vascular compromise in bowel obstruction?

Answer 12

Strangulation compromises blood supply

Leads to ischaemia –> necrosis of bowel

Question 13

What causes sepsis in bowel obstruction?

Answer 13

Perforation –> leaking of faecal matter into peritoneum

Severe infection, hard to clear

Question 14

What investigations are appropriate in a patient with suspected bowel obstruction?

Answer 14

Bloods

• FBC
• CRP
• U&Es
• LFTs
• Amylase
• ABG- metabolic alkalosis

AXR
-to distinguish type of obstruction

CT
-to determine level and cause of obstruction

Urinalysis

Question 15

What is bowel obstruction?

Answer 15

Blockage in the intestines
Often affects small intestine more
Leads to hypovolaemia and shock due to decreased fluid absorption causing decreased intravascular fluid

Higher up the obstruction the worse the dehydration

Question 16

What are symptoms of LBO?

Answer 16

Abdominal pain
Abdominal distension
Absolute constipation- early sign
N&V- late sign
Signs of underlying cause e.g. weight loss if cancer

Question 17

What are causes of paralytic ileus?

Answer 17

Post operatively (within 4days)
Electrolyte imbalance
Severely unwell pt with multiple injuries
Anastomotic leaks or abdo sepsis

Question 18

What are signs of strangulated obstruction?

Answer 18

Worsening pain and abdo distension
Leucocytosis
Systemic upset
Peritonism

Question 19

What is the management of SBO?

Answer 19

A-E
IV fluids
NBM
NG tube for free drainage

Conservative management can help some people
If not surgery required

Question 20

What is the management of LBO?

Answer 20

A-E
IV fluids
NBM
NG tube for free drainage

In constipation causes can try enemas and laxatives

If not Hartmanns surgery often required

Question 21

What is the management of strangluation?

Answer 21

Abx and straight to theatre