bowel obstruction and ileus

Question 1

define bowel obstruction

Answer 1

a blockage often due to a physical object being in the way.

you get dilation of the bowel proximal to the obstruction. results in large amounts of fluids being secreted into the bowel. (venous obstruction, edema as a result, if v bad then arterial obstruction and ischaemia)

Question 2

aetiology of bowel obstruction (small and large)

Answer 2

Large Bowel: tumor (pedunculated adenocarcinoma most common)
diverticular structures
sigmoid volvulus (coffee bean sign on CT, wrapped around its mesenteric attachment)
chronic constipation (overflow diarrhoea)

smol: adhesions, chrons, hernias. volvulus, intussusception, ileus

Question 3

what is volvulus, what happens and Rx of.

Answer 3

loop of bowel has completely twisted around its site of mesenteric attachment, § Complications of this: ischaemia + perforation

§ Gets massively inflamed due to trapped gas produced by gut bacteria that is contained within the loop
§ Creates a coffee bean sign on the AXR
§ Mx with a sigmoidoscopy, 2nd line is laparotomy and then last line is Hartmann’s procedure

Question 4

Intussusception what is it and how Rx

Answer 4

Prolapse of one part of the intestine into the lumen of the immediately adjoining bowel. quite serious.

§ Most of the time this is in the ileocolic region

§ Mostly seen in children as they have lots of lymphoid tissue within their bowel. This is usually benign, and treatment is reduction with air, water and barium

§ Less common in adults and is usually due to polyps, tumours or lymphomas. Mx is almost always surgical resection of that section of the bowel.

§ Can also do a barium swallow to investigate this

Question 5

ileus, what is it

Answer 5

o The reaction of the bowel to any form of irritation around it
Characterised by cessation of normal peristaltic movements of the bowel

Causes:
§ Post-operative => any handling of the bowel at surgery
§ Generalised peritonitis => perforation, severe acute pancreatitis, etc
§ Drugs => opiates
§ Electrolyte imbalances => hypokalaemia

o Ileus mimics mechanical obstruction since it also causes abdominal distension with constipation and vomiting

§ However, ileus does not itself cause pain => there is often pain (which is not usually colicky) due to the underlying disorder causing it

Question 6

S+S and Ix + Rx of bowel obstruction

Answer 6

Clinical signs and symptoms
· Colicky pain
· Abdominal distension
· Vomiting due to the mechanical obstruction, and the pressure is building up
· Absolute constipation => neither flatus nor faeces are passed

Investigations + Management
· Abdominal XR
· Bloods inc. VBG, clotting, G+S
· Fluid resuscitation
· Anti-emetics => but DO not give metoclopramide

o Put in an NG-tube to allow free-drainage of the stomach contacts. this releases a lot of pressure

· Keep patient NBM
· Treat the underlying cause (may require surgery)
If it’s large bowel obstruction, feel for abdominal masses and do a DRE

Question 7

differential diagosis of Bowel obstruction + complications and prognosis

Answer 7

gastroenteritis, mesenteric ischemia, acute pancreatitis, constipation.

bowel necrosis + perf, wound dehiscence, intra-abdominal abcess, aspiration, short bowel syndrome.

mortality 2-8% upto 25% if ischaemia present.

Question 8

where in the bowel do you perforate

Answer 8

the largest diameter area- which in the large bowel is the caecum