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
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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
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3
Q

What are the differential diagnoses of SBO?

A
  • Gastric outlet obstruction (eg duodenal ulcer or stomach malignancy)
  • Infection conditions
  • Ascites, carcinomatosis
  • Pancreatitis
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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
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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
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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
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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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