Bowel obstruction Flashcards
What is more common, small or large bowel obstruction?
Small bowel obstruction
Why does bowel obstruction cause fluid losses?
Fluid is secreted by the bowel that is then usually absorbed in the distal colon. When this reabsorption cannot occur, this leads to fluid losses from the intravascular space into the GI tract. This is known as “third spacing”
3 biggest causes for bowel obstruction?
“TAH”
Tumours
Adhesions
Hernias
Other causes include volvulus, diverticular disease, strictures and intussusception (paeds 6 months-2 years)
What are adhesions?
Scar tissue that bind abdominal contents together.
This causes kinking and squeezing of the bowel. Often more common in small bowel.
What are the causes of adhesions?
Abdomino-pelvic surgery - more often open Peritonitis Abdominal/pelvic infections Endometriosis Congenital Iatrogenic - radiotherapy
What is it called when there are two points of obstruction in a bowel causing a middle section between the two?
Closed loop bowel obstruction.
What causes a closed loop obstruction?
Hernias
Adhesions
Volvulus
Single point of obstruction in the large bowel and a competent ileocaecal valve.
Complications of closed loop bowel obstruction?
Ischaemia and perforation.
Requires emergency surgery.
Clinical presentation of bowel obstruction?
Vomiting - green and bilious Abdominal distension Diffuse abdo pain Constipation Lack of flatulence Bowel sounds - tinkling
What is the key finding of bowel obstruction in AXR?
Distended loops of bowel
What are the upper limits of the normal diameter of small bowel, colon and caecum?
Small bowel 3cm
Colon 6cm
Caecum 9cm
What is the name for the mucosal folds that form lines extending the full width of the bowel?
Plicae circulares OR Valvulae conniventes
What is the name for the pouches formed by the muscles in the walls of the bowel, which form lines that do not extend the full width of the bowel on an abdominal x-ray?
Haustra, found in the large bowel.
What does a raised serum lactate suggest in a patient with bowel obstruction?
Bowel ischaemia
What is the name of the condition affecting the small bowel, where the normal peristalsis that pushes the contents along the length of the intestines, temporarily stops?
Ileus
When are you most likely to find a patient with ileus?
Post operatively or with electrolyte imbalance
What are the two types of volvulus and which type is more common?
Caecal and sigmoid. Sigmoid is more common.
What might you find on investigative bloods in bowel obstruction?
Electrolyte imbalances
Metabolic alkalosis - due to excessive vomiting
Raised lactate
What is the initial management for bowel obstruction?
Drip and suck
IV fluids to hydrate the patient and correct electrolyte imbalances
NG tube
First line investigation for bowel obstruction?
Abdominal x-ray is initial investigation however if patient is presenting acutely CT scan is usually carried out.
Erect CXR used to demonstrate abdominal perforation
Gold standard diagnostic investigation for bowel obstruction?
Contrast abdominal CT scan is usually required to confirm the diagnosis and establish the site and cause.
Can also be used to diagnose intra-abdominal perforation
Management of sigmoid volvulus?
Conservative management initially - if sigmoid volvulus does not self resolve within 48 hours, then:
- Sigmoidoscopy to locate correct area of twisted bowel
- Flatus tube inserted to relieve compression (left in situ for up to 24 hours)
When is surgery indicated in a sigmoid volvulus?
- Advanced volvulus - ischaemic/necrotic
* Repeated failed attempts at decompression
What surgical intervention is carried out if required in volvulus?
A laparotomy for Hartmann’s procedure (necrotic sigmoid bowel removed and end colostomy formed)
Management of a caecal volvulus?
Cecopexy - surgical manipulation to place the caecum back into rightful position
Definitive management is laparotomy with ileocaecal resection or right hemicolectomy.
What is the mesentery?
The mesentery is the membranous peritoneal tissue that creates a connection between the bowel and the posterior abdominal wall.
What are the key risk factors for a sigmoid volvulus?
Chronic constipation
Lengthening of the mesentery that is attached to the sigmoid colon.
High fibre diet
Pregnancy
Adhesions
