Small Bowel Obstruction Flashcards
(37 cards)
What happens to bowel proximal to an obstruction
Becomes dilated with air and fluid
How does an upper SBO present
Acute presentation
Hours of onset
Large volumes of gastric, pancreatic and biliary secretions are regurgitated into the stomach and committed as they can’t pass through the bowel
How does a distal/large bowel obstruction present
Colicky abdominal pain and distension
Vomiting possible faeculent
General symptoms of intestinal obstruction
Vomiting Pain Constipation Distension Complete obstruction Incomplete obstruction
What determines how early vomiting developed
Where the obstruction is
More proximal obstructions - vomiting starts earlier
Can occur even when nothing is taken by mouth as GI secretions continue to be produced and vomited up
Vomitus of semi-digested food eaten a day or to previously with no bile suggests what kind of obstruction
Gastric outlet obstruction
Vomitus of copious amounts of bile-stained fluid suggests what kind of obstruction
Upper small bowel obstruction
vomitus of thick brown, foot smelling ‘faeculent’ fluid
Distal bowel obstruction
What causes the pain in intestine obstruction
Distension of the bowel gives intermittent episodes of colicky pain
How does intestinal obstruction cause constipation
Propulsion of bowel contents stopped
bowel gas is absorbed distal to the obstruction
What is ‘absolute constipation”
No faeces or gas passed
Symptoms of large bowel obstruction developed more quickly true/false
False
develop more gradually due to the large capacity of the colon and caecum and their absorptive activity
In what percentage of large bowel obstruction cases does the ileocaecal valve remain competent
50%
When it is competent it prevents backward flow of bowel contents
If it is incompetent the small bowel distends delaying onset of symptoms
Why does the caecum rupture
Because it is thin walled and progressively distends with swallowed air
‘closed loop obstruction’
What is incomplete obstruction
Bowel only partially obstructed and clinical features less defined
Vomiting intermittent and bowel habits erratic ect.
What causes hypertrophy of the muscle of the bowel wall
chronic incomplete construction
What are some physical signs of intestinal obstruction
Dehydration Abdominal distension Visible peristalsis Relative lack of abdominal tenderness Obstruction abdominal mass may be palpable Resonant percussion due to gas Groin may have obstructing hernia
Bowel obstruction with tenderness
Bowel strangulation
What do bowel sounds sound like in intestinal obstruction
High-pitched and tinkling
What investigations to do for SBO
Abdo x-ray - shows bowel proximal to obstruction distended with gas
CT - confirms diagnosis and look for cause
Where do distended small bowel loops lie on AXR
Central
Where does the distended large bowel sit on AXR
Anatomical position and has haustra coli
What does a CT of a bowel obstruction show
Distended bowel proximal to obstruction and collapsed bowel distal
Initial management of intestinal obstruction
Nil by mouth
Insert IV cannula and send blood
Resuscitate with IV fluids replacing electrolyte losses
Pass a nasogastric tube to decompress the stomach
