Bowel Obstruction Flashcards
What is the difference between a mechanical bowel obstruction and a paralytic ileus?
Mechanical - physical blockage
Paralytic ileus - cessation of normal gut peristalsis
What is the main cause of a paralytic ileus and how is it defined?
- Post-operative
2. Ileus for more than 3 days after surgery
What are the risk factors for paralytic ileus?
Generalised peritonitis, pancreatitis, spinal injury, hypokalaemia, hyponatraemia, uraemia, drugs (TCAs).
What is this a presentation of?
Vomiting, absolute constipation, colicky abdominal pain. Anorexia, abdominal distension.
Small bowel obstruction
What are the main causes of small bowel obstruction?
- Adhesions - common post-operatively
- Hernias
- Crohn’s, appendicitis, intestinal malignancy
What are the causes of small bowel obstruction in children?
Intussusception, volvulus, appendicitis
What is a simple small bowel obstruction?
One obstructing point and no vascular compromise.
What is a closed small bowel obstruction?
Obstruction at two points (sigmoid volvulus) forming a loop of grossly distended bowel at risk of perforation. Cannot decompress.
What is a strangulated small bowel obstruction?
Blood supply compromised. Sharper, more constant and localised pain. Peritonism id the cardinal sign. Fever.
How is a suspected small bowel obstruction investigated?
- Erect CXR - partial shows gas in rectum, complete shows no digital gas, complicated shows pneumoperitoneum and thumbprinting.
- CT to establish cause
- High WCC
What is the management for a small bowel obstruction?
- Partial resolves conservatively
- Complete and strangulated are surgical emergencies.
- Drip and suck - NG tube decompression and IV fluids
- Analgesia, antibiotics, catheter to monitor fluid output.
What are the main causes of a large bowel obstruction?
- Colorectal malignancy
- Colonic volvulus (sigmoid > caecal)
- Crohn’s strictures, diverticular strictures.
What is this a presentation of?
Colicky abdominal pain, abdominal distension, altered bowel habit. Nausea and vomiting. Tympanic abdomen.
Large bowel obstruction
How is a suspected large bowel obstruction investigated?
- FBC, U&Es, coagulation, amylase/lipase
- Plain AXR - 3cm (SBO), 6cm (colon), 12cm (caecum) upper diameter limit.
- Contrast enema/abdominal CT if doubts on AXR
What is the management for a large bowel obstruction?
- NBM
- Oxygen if hypoxic
- Drip and suck
- IV fluids for dehydration and electrolyte abnormalities.
- Catheter to monitor fluid output.
- Surgery usually indicated in all patients
