Small Bowel Obstruction Flashcards
1
Q
What is the aetiology of SBO?
A
Within the lumen
- Gallstones
- Food bolus
- Bezoars
- Parasites (eg Ascaris)
- Enterolith
- Foreign body
Within the wall
- Inflammation (crohns/ radiation enteritis)
- Infection (TB)
- Ischaemia (SMA embolus/ SMV thrombosis)
- Tumour (primary/ secondary)
Outside the wall
- Adhesions (congential/ aquired)
- Hernia (inguinal, femoral, incisional, umbilical, internal)
- Intussusception
- Volvulus
2
Q
What are the symptoms and signs of SBO?
A
4 cardinal features;
- Vomitting
- Faecalant vomitting (faecal is caused by fistula)
- Colicky central abdo pain
- Constipation (absolute)
- Distension
3
Q
What are the differential diagnoses of SBO?
A
- Gastric outlet obstruction (eg duodenal ulcer or stomach malignancy)
- Infection conditions
- Ascites, carcinomatosis
- Pancreatitis
4
Q
What is the definition and differences between simple, closed lopp and strangulated obstructed bowel?
A
Simple
- 1 obstructing point & no vascular compromise
- Closed-loop
2 obstruction points
- Forming loop of grossly distended bowel at risk of perforation
Strangulated
- Compromised blood supply
- Sharper, more constant, localized pain than the central colic of obstruction
- Peritonism is cardinal sign
- Fever, inc. WBC and other signs of mesenteric ischaemia
5
Q
What is an ileus? And what is the difference between an ileus and mechanical obstruction?
A
Ilius is the loss of GI motility.
- Only refers to loss of peristalisis (not obstruction generally)
Differenes between ilius and obstruction;
- Ilius has no pain
- Ilius has absent bowel sound
6
Q
What investigations would you perform in suspected SBO?
A
- Ealier vomiting
- Less distension
- More pain
- AXR
- Central gas shadows with valvulae conniventes (cross the lumen)
- Consider gallstone ileus - calcified gallstone & possible air in biliary tree (confirm by USS)
- FBC
- U&E
- LFTs/ amylase/ CRP
- Clotting studies
- Arterial blood gases (metabolic acidosis may indicate bowel ischaemia)
- CT
- Useful in malignant LBO as also identifies metastases
- Contrast radiology
7
Q
Outline the management of SMO
A
- Drip & suck (IV fluids & NGT)
- Analgesia
- Oxygen
- Stop motility stimulants & ensure alternative routes for any medications
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