Intestinal Obstruction Flashcards
What are most intestinal obstructions due to.
Due to mechanical block.
What is a common occurrence after abdominal surgery.
Paralytic ileus.
What are some causes of small bowel obstruction. (5)
Adhesions (80% in adults). Hernias. Crohn's disease. Intessusception. Obstruction due to extrinsic involvement by cancer.
What are some causes of colonic obstruction. (4)
Carcinoma of the colon.
Sigmoid or caecal volvulus.
Diverticular disease (strictures).
Constipation.
What are the cardinal features of intestinal obstruction. (4)
Vomiting.
Colicky pain.
Constipation.
Distension.
What is the most common cause of small bowel obstruction.
Adhesions.
What are the rare causes of bowel obstruction. (5)
Crohn's disease. Gallstone ileus. Intussusception. TB (developing world). Foreign body.
What occurs in established intestinal obstruction.
Fermentation of the intestinal contents causes ‘faeculent’ vomiting.
What sound is typically heard on auscultation of an obstructed bowel.
Tinkling bowel sounds.
What is seen on AXR in small bowel obstruction. (3)
Central gas shadows with valvulae conniventes that completely cross the lumen.
No gas in the large bowel.
What is seen on AXR in large bowel obstruction. (3)
Peripheral gas shadows proximal to the blockage (eg in caecum).
No gas in the rectum (unless introduced by PR exam).
Large bowel haustra do not cross all the lumen’s width.
What distinguishes small bowel obstruction from large bowel obstruction. (3)
In small bowel obstruction, vomiting occurs earlier.
There is less abdominal distention.
Pain is higher in the abdomen.
What are the features of ileal bowel obstruction. (3)
Functional obstruction from reduced bowel motility.
No pain.
BS are absent.
What is a simple bowel obstruction. (2)
One obstructing point.
No vascular compromise.
What is a closed loop bowel obstruction. (3)
Obstruction at two points forming a loop of grossly distended bowel.
At risk of perforation.
>12cm requires urgent decompression.
What is a strangulated bowel obstruction. (7)
Blood supply is compromised.
The patient is more ill than you would expect.
There is sharper, more constant and LOCALISED pain.
Peritonism if a cardinal sign.
There may be fever, raised WCC and other signs of mesenteric ischaemia.
What must occur for there to be complete bowel obstruction. (2)
No passage of stools or flatus.
What symptom may be absent in lower bowel obstruction.
Vomiting.
What are the physical signs of bowel obstruction. (2)
Abdominal distention.
Tinkling or absent bowel sounds.
What does marked abdominal tenderness suggest on an abdominal exam.
Strangulated bowel obstruction.
What other areas must be examined in a patient with a bowel obstruction. (2)
Hernial orifices.
Rectum.
What is the investigation of choice in bowel obstruction.
CT - as it can localize the lesion accurately.
What is acute colonic pseudo obstruction. (2)
A clinical picture mimicking mechanical obstruction.
Management is by withdrawing the underlying problem (eg opates, analgesics).
