Bowel Obstruction, Gastric Outlet Obstruction And Pseudo-obstruction Flashcards
What does bowel obstruction mean?
Mechanical blockage of the bowel. Leading to gross dilation of the proximal limb of the bowel which results increased peristalsis and secretions of large volumes of electrolyte-rich fluid (third spacing).
What is closed loop obstruction?
When the is a second obstruction proximally - such as in volvulus or in large bowel obstruction with competent ileocaecal valve)
Surgical emergency as bowel will continue to distend, stretching until it becomes ischaemia or perforates.
What are the most common causes of small bowel obstruction?
Adhesions
Hernia
What are the most common causes of large bowel obstruction?
Malignancy
Diverticular disease
Volvulus
What are the three categories of cause for bowel obstruction and give some examples of each?
Intraluminal - gallstone ileus, ingested foreign body, faecal impaction
Mural - cancer, inflammatory strictures, interssusception, diverticular strictures, meckels diverticulum, lymphoma
Extramural - hernias, adhesions, peritoneal metastasis, volvulus
What are the symptoms of bowel obstruction?
Abdominal pain - colicky/cramping
Vomiting - early in proximal obstruction
Abdominal distension
Absolute constipation - early in distal obstruction
What may be seen on examination of someone with bowel obstruction?
Abdominal distension
Underlying cause - surgical scars, cachexia (malignancy)
Fluid status - third-spacing
Tympanic sound on percussion and auscultation may reveal tinkling bowel sounds
Focal tenderness - rebound tenderness or guarding indicate ischaemia developing
What are the differential diagnosis of bowel obstruction?
Pseudo-obstruction
Paralytic ileus
Toxic megacolon
Constipation
What are the investigations ordered in suspected bowel obstruction?
Urgent bloods - G&S, VBG
Imaging:
- CT with IV contrast of abdomen and pelvis
- AXR
- Erect CXR - suspected bowel perforation?
- Water soluble contrast study - small bowel obstruction
Why are CT IV contrast more useful then AXR in bowel obstruction?
More sensitive for bowel obstruction
Can differentiate between mechanical and pseudo-obstruction
Can demonstrate site and cause of obstruction - operative planning
May demonstrate the presence of metastases if caused by malignancy
What is the evidence if ischaemia in bowel obstruction?
Pain worsened by movement
Focal tenderness
Pyrexia
What is the initial management of bowel obstruction?
Urgent fluid resuscitation
Urinary catheter
If evidence of ischaemia - urgent surgery
When is conservative management used in bowel obstruction and what is it?
Absence signs of ischaemia or strangulation:
- NBM + NG time to decompress bowel
- Start IV fluids - correct electrolyte balance
- Urinary catheter and fluid balance
- analgesia and antiemetics as required
What should be done if small bowel obstruction doesn’t resolve within 24hrs of conservative management?
Water soluble contrast study - if doesn’t reach colon by 6 hours then unlikely to resolve - take to theatre
What is a virgin abdomen and what is the significance?
Patient who has not had previous surgery
Bowel obstruction rarely settles without surgery