Bowel Obstruction Flashcards
What is a small bowel obstruction?
Mechanical disruption in the patency of the GI tract, resulting in a combination of emesis (that may
be bilious), obstipation, and abdominal pain.
What are the most common causes of SBO?
- previous surgeries (adhesion)
- malignancy
- inguinal hernia
What is the pathophysiology of SBO?
- proximal dilation causes vomiting and abdominal cramping
- distal interruption causes obstipation
What are symptoms of SBO?
- failure to pass flatus or stool
- abdominal pain (crampy and intermittent, and can be severe)
- vomiting
- abdominal distention
What are physical exam findings for SBO?
- abdominal distention
- mild diffuse 4-quadrant abdominal tenderness
- increased pitch of bowel sounds
They appear ill, with fever and mild dehydration. A mass may be palpated in the abdomen,
What is the history of SBO?
A detailed history provides insights into the onset and timing of the abdominal pain, the nature of the vomiting (which may be bilious), and the history of passage of stool or flatus.
What are investigations for SBO?
- abdominal x-ray (supine and erect)-may show air-fluid, dilated intestinal loops
- FBE
- Urea
- Electrolytes
What are DDx for SBO?
- Ileus
- Infective gastroenteritis
- Large bowel obstruction
- Appendicitis
- Pancreatitis
What is treatment for SBO?
- Nasogastric tube and fluid resuscitation
- Anti-emetics
- Anti-spasmodics (pain)
- Surgery if indicated
What is a large bowel obstruction?
Surgical emergency where a mechanical interruption (either complete or partial) occurs to the flow
of intestinal contents, with multiple potential causes (e.g., malignant colorectal disease, colonic volvulus, benign stricture)
What is the main causes of LBO?
- malignant disease (90%)
- colonic volvulus (5%)
What is the pathophysiology of LBO?
- proximal dilation causes increased colonic pressure, reduced mesenteric blood flow and mucosal oedema
- fluid moves into lumen, reduces arterial supply and then ischaemia
- ischaemia can cause perforation
What is the presentation of LBO?
- colicky abdominal pain
- abdominal distention
- tympanic abdomen
- change in bowel habits
- hard faeces (faecal impaction)
What are important aspects of the history of LBO?
A thorough history should be noted and generally depends on the cause of obstruction.
Colorectal malignancy: Gradual onset, constitutional symptoms
Colonic volvulus: Abrupt onset
What are findings on a physical exam in LBO?
Abdominal distension in the distribution of the affected colonic segments and tympanic abdomen
are common to all causes of mechanical obstruction.
Severe tenderness and abdominal rigidity imply peritonitis secondary to perforation.
