Bowel obstruction**** Flashcards
What is a simple open-loop obstruction?
What is a closed-loop obstruction? Causes
What is a strangulated obstruction?
One obstruction point (open) and no vascular compromise.
There’s proximal and distal compression - caused by sigmoid volvulus - causes grossly distended bowel at risk of perforation
Blood supply compromised and the patient is a lot iller than you would expect.
Pain is sharper, constant and more localised.
Causes:
Luminal - 4
Intramural (within wall) - 4
Impacted faeces
Gallstone ileus
Large polyp
Foreign body
Tumour
Strictures - Crohns or diverticulitis
Intussusception - suggests tumour if it occurs in adults
Infarction
Causes:
Extramural - 4
Adhesions - surgery, IBD
Incarcerated hernias
Volvulus - sigmoid, caecal or small bowel
Compression (e.g. a tumour in a neighbouring organ)
Commonest causes of small bowel obstruction - 2 AND WHY?
Adhesions
Strangulated hernias
THEY DON’T EFFECT LARGE BOWEL AS IT IS TETHERED IN PLACE
What is the commonest cause of large bowel obstruction?****
2 other common causes
Colorectal cancer***
Volvulus
Diverticulitis
What 3 questions you should ask yourself?
(1) Is it in the small or large bowel?
(2) Is there an ileus or mechanical obstruction?
(3) Is it simple/closed/strangulated?
What are ileus and pseudo-obstruction?
Why are they significant?
Reduced bowel motility in the absence of mechanical obstruction - NEXT CARD GOES INTO MORE DETAILS
It presents very similarly to bowel obstruction as you get bowel dilatation.
Paralytic ileus (end of small bowel):
What are the causes? - 2
How is it usually managed?
Stress from surgery (especially GI) or systemic illness
Conservative sufficient
Pseudo-obstruction (large bowel):
What is the pathophysiology? - 2
How is it decompressed?
What is Ogilvie syndrome?
Increased sympathetic tone
Decreased parasympathetic tone
Decompressed with colonoscopy
The acute dilatation of the colon in the absence of any mechanical obstruction in severely ill patients. Acute colonic pseudo-obstruction is characterized by massive dilatation of the cecum (diameter > 10 cm) and right colon on abdominal X-ray.
Cardinal symptoms:
First symptom
Second symptom if high small bowel obstruction
Second symptom if low small bowel obstruction
Second symptom if large bowel obstruction
Abdominal pain - usually colicky due to increased peristalsis
Vomiting
Abdominal distention
Constipation - may be absolute (obstipation) with no flatus or faeces.
Signs:
What could you find on palpation? - 1
What does the percussion sound like? - 1
What do you hear on auscultation in obstruction and paralytic ileus ?
Tenderness
Tympanic percussion - drum-like sounds heard over air-filled structures during the abdominal examination. Hyperresonant (pneumothorax) said to sound similar to the percussion of puffed-up cheeks. Normal resonance - the sound produced by percussing a normal chest.
Tinkling bowel sounds
Nothing in ileus
Signs:
What does a scar indicate?
What else do you need to look for on examination that could cause small bowel obstruction?
What indicates perforation?
Adhesions
Hernia in inguinal areas
Fever and shock
Where in the small or large bowel is more likely to perforate?
Caecum in large bowel as it is thin-walled
Investigations:
Bloods:
- Why do FBC? - 2
- Why do U&E? - 2
- Why do lactate?
What needs to be done pre-op?
Infection
Anaemia
Dehydration
Hypokalaemia from vomiting
Raised lactate in bowel ischaemia in strangulation
Coagulation and ‘group and save’
Investigations:
What is the main imaging used?
What sign on barium enema could show caecal or sigmoid volvulus?
What would you see on erect CXR if there was perforation?
Strangulated bowel won’t be able to take up the contrast. What imaging can be used then?
Suprine AXR
Bird peak sign - look at pics
Air under the diaphragm - pneumoperitoneum
Abdo-pelvis CT
