Gashtro 2 Flashcards
Describe the epidemiology of small bowel obstructions (SBO)
Most common bowel obstruction (60-75%)
What are 4 causes of SBO?
- Adhesion (~60%) (due to previous abdo/pelvic surgery or abdo infection)2. Hernias (intestinal contents cannot pass through strangulated loop)3. Malignancy4. Crohn’s disease
Describe the pathophysiology of intestinal obstructions
- Obstruction of bowel leads to distension above blockage due to build-up of fluid and contents- Causes increased pressure which pushes on the blood vessels within the bowel wall causing them to become compressed- Compressed vessels cannot supply blood resulting ischaemia and necrosis and eventually perforation
What are 3 signs of SBO?
- Abdominal distension2. Increased bowel sounds (tinkling)3. Tenderness (suggests strangulation/risk of perforation)
What are 3 symptoms of SBO?
- ‘Colicky’ pain higher in abdomen2. Profuse vomiting3. Constipation with no passage of gas (occurs later)
What are the investigations for patients with SBO?
- Abdominal x-ray (1st line)- Examination of hernia orifices and rectum- FBC- Non contrast CT (gold standard - localises obstruction)
What does an abdominal x-ray look like in patients with SBO?
- Central gas shadow that completely crosses lumen- No gas seen in large bowel- Distended loops proximal to obstruction- May see fluid levels within bowel
What is the treatment for intestinal obstructions?
- Aggressive fluid resuscitation- Decompression of bowel (drip and suck, IV fluids with NG tube)- Analgesia and anti-emetics- Antibiotics- Laparotomy
Describe the epidemiology of large bowel obstructions (LBO)
LBO due to malignancy much more common in the EU/West than in Africa
What are 5 causes of LBO?
- Malignancy2. Volvulus (rotation/twisting of bowel on its mesenteric axis - commonly sigmoid colon)3. Diverticulitis4. Crohn’s disease5. Intussusception (bowel rolls inside of itself - almost exclusively in neonates/infants due to ‘softer’ bowels)
What are 3 signs of LBO?
- Abdominal distension (much more than SBO)2. Palpable mass e.g. hernia (most common in LIF)3. Normal bowel sounds initially and eventually silent
What are 3 symptoms of LBO?
- Abdominal pain in lower abdomen, especially LIF (more constant and diffuse than SBO)2. Vomiting3. Constipation with no passage of gas
What are the investigations for patients with LBO?
- Abdominal x-ray (1st line)- Digital rectal exam (DRE)- FBC- CT (gold standard)
What does an abdominal x-ray look like in patients with LBO?
- Peripheral gas shadows proximal to blockage- Caecum and ascending colon = distended
What does a digital rectal exam (DRE) look like in patients with LBO?
- Empty rectum- Hard, compacted stools- Might be blood
What is a pseudo-obstruction?
Condition in which a patient has symptoms of intestinal obstruction but does not actually have anything blocking the intestines
What are 5 causes of pseudo-obstructions?
- Intra-abdo trauma2. Post-operative states e.g. paralytic ileus3. Intra-abdo sepsis4. Drugs e.g. opiates/antidepressants5. Electrolyte imbalances
How do pseudo-obstructions present?
Identically to SBO/LBO
What is the treatment for pseudo-obstruction?
Treat underlying cause
What is Crohn’s disease?
Intermittent chronic inflammation of the entire GI tract
Describe the epidemiology of Crohn’s disease
- Presentation mostly in 20s-40s- Common in Northern European- Jewish people = most affected group- 400/100,000 in UK- Affects females more than males
What are 5 risk factors for Crohn’s disease?
- Smoking (2-4x greater risk)2. NSAIDs3. Jewish4. Female5. Family history
What are 4 causes of inflammatory bowel disease?
- Genetics (stronger association in Crohn’s than UC)2. Stress3. Depression4. Immune response
Describe the pathophysiology of Crohn’s disease
- Transmural inflammation with granulomata- Occurs anywhere in the GI tract- Skip lesions- Deep ulcers and fissures (cobblestone appearance)