Bowel disease Flashcards
Bowel obstruction : Definition
bowel obstruction refers to a mechanical blockage of the bowel, whereby a structural pathology physically blocks the passage of intestinal contents.
* bowel obstructioncan affect the small bowel, the large bowel, or both
Bowel obstruction : Pathophysiology
- Blockage of the bowel due to structual pathology
- Gross dilatation of proximal bowel
- Results in; excess secretion of large volume of electrolyte rich fluid in the bowel (Third spacing)
* Dehydration/AKI may occur - Closed loop obstruction
* Second obstruction point proximillay - ie. structual blockage with proximal closed vale
* Surgical emergency - as pressure build up in closed bowel and can lead to ischaemia and perforation
Bowel obstruction : Causes
Outside of bowel : Hernia, peritoneal metastasis, volvulus
Small bowel : adhesions or hernia, Gallstone ileus, inflammatory strictures
Large bowel : malignancy, diverticular disease, or volvulus, faecal impaction,
Bowel obstruction : Clinical features
- Abdominal pain – colicky or cramping in nature (secondary to the bowel peristalsis)
- Vomiting – occurring early in proximal obstruction and late in distal obstruction
- Abdominal distension
- Absolute constipation – occurring early in distal obstruction and late in proximal obstruction
Bowel obstruction : Examination
- Fluid status - risk of dehydration and AKI due to third space losses
- Focal tenderness - guarding/rebound tenderness may indicate ischaemic bowel
- Bowel sounds : Tympanic on percussion, ‘tinkling’ bowel sounds
Bowel obstruction : Investigation
Gold standard : CT scan with intravenous contrast of the abdomen and pelvis
Initial : AXR
* Small bowel obstruction : >3cm diameter of small bowel, vulvulae visible (lines completely crossing bowel)
* Large bowel obstruction : >6cm diameter, peripheral location and haustal line (do not completely cross bowel)
Bowel obstruction : Initial management
- IV fluid resuscitation
- Nasogastric tube
- Urinary catheter
Bowel obstruction : Conservative mx
Indication : no signs of ischaemia or perforation
1. NBM
2. NG tube - to decompress bowel
Bowel obstruction : Surgical mx
Indication : Ischaemia/Perforation, closed bowel obstruction, strangulating hernia/tumor
or >48 hours of conservative mx without improvement
- Surgical laprotomy +/- stoma
Bowel obstruction : Complication
- Bowel ischaemia
- Bowel perforation leading to faecal peritonitis (high mortality).
Functional bowel obstruction : Defintion
Failure of bowel peristalsis - not due to structual obstruction, no mechanical cause
Functional Bowel obstruction : Causes
- Pseudo-obstruction
- Post-operative ileus
Pseudo-obstruction : Definition
Pseudo-obstruction is a disorder characterised by dilatation of the colon due to an adynamic bowel, in the absence of mechanical obstruction.
- The disorder most commonly affects the caecum and ascending colon, however can affect the whole of the large colon.
Pseudo-obstruction : Pathophysiology
- Due to an interruption of the autonomic nervous supply to the colon resulting in the absence of smooth muscle action in the bowel wall.
Untreated cases can result in an increasing colonic diameter, leading to an increased risk of bowel ischaemia and bowel perforation.
Pseudo-obstruction : Causes
- Electrolyte imbalanceor endocrine disorders, such as hypercalcaemia, hypothyroidism, or hypomagnesaemia
- Medication, including opioids, calcium channel blockers, or anti-depressants
- Recent surgery, severe systemic illness, or trauma
- Neurological disease, including Parkinson’s disease or Multiple Sclerosis
