Gastrointestinal 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)
- Hernias (intestinal contents cannot pass through strangulated loop)
- Malignancy
- 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 distension
- Increased bowel sounds (tinkling)
- Tenderness (suggests strangulation/risk of perforation)
What are 3 symptoms of SBO?
- ‘Colicky’ pain higher in abdomen
- Profuse vomiting
- 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?
- Malignancy
- Volvulus (rotation/twisting of bowel on its mesenteric axis - commonly sigmoid colon)
- Diverticulitis
- Crohn’s disease
- 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)
- Palpable mass e.g. hernia (most common in LIF)
- 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)
- Vomiting
- 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 trauma
- Post-operative states e.g. paralytic ileus
- Intra-abdo sepsis
- Drugs e.g. opiates/antidepressants
- 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)
- NSAIDs
- Jewish
- Female
- Family history
What are 4 causes of inflammatory bowel disease?
- Genetics (stronger association in Crohn’s than UC)
- Stress
- Depression
- 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)
What are 3 signs of Crohn’s disease?
- Bowel ulceration
- Abdominal tenderness
- Abdominal mass
What are are 2 symptoms of Crohn’s disease (in the small bowel)?
- Weight loss
- Abdominal pain
What is a symptom of Crohn’s disease (in the terminal ileum)?
Right iliac fossa pain mimicking appendicitis
What are 2 symptoms of Crohn’s disease (in the colon)?
- Blood and mucous with diarrhoea
- Pain
What are 2 extra-intestinal symptoms of Crohn’s disease?
- Clubbing
- Oral aphthous ulcers
What are 6 investigations for inflammatory bowel disease?
- Sigmoidoscopy
- Colonoscopy with rectal biopsy (gold standard)
- Bloods (raised WCC/platelets/CRP/ESR)
- Stool samples
- Abdominal x-ray
- Faecal calprotectin = raised
What is the treatment for Crohn’s disease?
- Stop smoking
- Corticosteroids e.g. prednisolone (remission)
- Anti-TNF antibodies e.g. infliximab, adalimumab (if no response to steroids)
- Thiopurines e.g. azathioprine (maintain remission)
- Surgery - resection/temporary ileostomy
What are 8 complications of Crohn’s disease?
- Bowel obstructions from strictures
- Short stature in children
- Osteoporosis
- Malabsorption
- Toxic dilatation
- Bowel perforation
- Abscess/fistula formation
- Colorectal cancer
What is ulcerative colitis?
Continuous chronic inflammation of only the colon
Describe the epidemiology of ulcerative colitis
- Higher incidence than Crohn’s
- Presentation mostly in teens-20s
- Common in Northern European
- Jewish people = most affected group
- 400/100,000 in UK
- Incidence is 3x higher in non-smokers
What are 3 risk factors for ulcerative colitis?
- Family history
- NSAIDs
- Jewish
Describe the pathophysiology of ulcerative colitis
- Mucosal inflammation only
- No granulomata
- Starts at rectum, can progress as far as the ileocecal valve
- Circumferential and continuous inflammation (no skip lesions)
- Ulcers and pseudo-polyps in severe disease
- Crypt abscesses and depleted goblet cells
What are 5 signs of ulcerative colitis?
- 90% have PSC
- Tender, distended abdomen
Extra-GI manifestations: - Arthralgia
- Fatty liver
- Gallstone
What are 7 symptoms of ulcerative colitis?
- Malaise
- Fever
- Anorexia
- Weight loss
- Pain in LLQ
- Abdominal cramps/discomfort
- Recurrent diarrhoea often with blood and mucus
What is the treatment for ulcerative colitis?
- Aminosalicylates e.g. mesalazine (intestinal anti-inflammatory - remission and relapse prevention)
- Corticosteroids e.g. prednisolone (remission)
- Thiopurines e.g. azathioprine and methotrexate (maintain remission)
- Surgery - colectomy
What are 8 complications of ulcerative colitis?
- Psychosocial and sexual problems
- Frequent relapse
- Colorectal cancer (risk doubled)
- Blood loss
- Perforation
- Toxic dilatation
- Pyoderma gangrenosum (painful ulcers)
- Erythema nodosum (tender red bumps)
What is the acronym for remembering Crohn’s?
NESTS
N - no blood/mucus
E - entire GI tract
S - skip lesions
T - terminal ileum is most affected, transmural inflammation
S - smoking is a RF
What is the acronym for remembering ulcerative colitis?
CLOSE UP
C - continuous inflammation
L - limited to colon and rectum
O - only superficial mucosa affected
S - smoking is protective
E - excrete blood and mucus
U - use aminosalicylates
P - primary sclerosing cholangitis association
What is irritable bowel syndrome (IBS)?
Mixed group of abdominal symptoms with no organic cause
Describe the epidemiology of IBS
- Age of onset under 40 years
- More common in females
- 1/5 in the Western World
What are 5 risk factors for IBS?
- GI infections
- Previous severe long-term diarrhoea
- Anxiety and depression
- Psychological stress/trauma/abuse
- Eating disorders
What are 4 pathophysiology theories of IBS?
- Disorders of intestinal motility
- Enhanced visceral perception
- Dysfunction of brain-gut axis
- Microbial dysbiosis (imbalance)
What are 7 differential diagnoses for IBS?
- Coeliac disease
- Lactose intolerance
- Bile acid malabsorption
- IBD
- Colorectal cancer
- GI infection
- Pancreatic insufficiency
What is the diagnosis criteria of IBS?
Abdominal pain/discomfort associated with 2+ of:
- Relieved by defecation
- Altered stool form
- Altered bowel frequency
What are 3 main symptoms of IBS?
ABC
- Abdominal pain/discomfort
- Bloating
- Change in bowel habit
What is the difference between IBS-C, IBS-D and IBS-M?
IBS-C = with constipation
IBS-D = with diarrhoea
IBS-M = mixed with alternating constipation and diarrhoea
What 4 things exacerbate symptoms of IBS?
- Stress
- Menstruation
- Gastroenteritis
- Food
What are 8 symptoms of IBS?
- Painful periods
- Bladder symptoms (frequency, urgency, nocturia, incomplete emptying)
- Back pain
- Joint hypermobility
- Fatigue
- Nausea
- Mucus in rectum/stool
- Hard/soft/mixed stool
What are 3 investigations for patients with IBS?
- Bloods
- Faecal calprotectin = raised
- Colonoscopy
What is the treatment for mild IBS?
Dietary modifications:
- Regular meals OR small frequent meals
- Plenty of fluids
- Avoid caffeinated, alcoholic, fizzy drinks
- Avoid fermentable oligosaccharides, disaccharides, monosaccharides and polyols
What is the treatment for moderate IBS?
Pharmacotherapy
- Antispasmodics (for pain/bloating) e.g. mebeverine, buscopan
- Loperamide (for diarrhoea) e.g. imodium
- Laxatives (for constipation) e.g. macrogol, docusate, sena
What are alternative laxative options for moderate IBS?
- Linaclotide if 12 months constipation not relieved by 2 different max dose laxative classes
- Prucalopride when all other laxatives fail
What is the treatment for IBS-C?
Soluble fibre:
- Dissolves in water
- Broken down by bacteria
- Soften stool
- E.g. barley, oats, beans, prunes, figs
What is the treatment for IBS-D?
AVOID soluble fibre:
- Makes diarrhoea worse
- Doesn’t dissolve in water
- Passes through gut unchanged
- Bulks up faeces
- Increases gut motility
- E.g. cereal, whole-wheat bread, lentils, apples, avacados
What is the treatment for IBS if ineffective?
- Tricyclic antidepressants (dampens down gut severity) e.g. amitriptyline, nortriptyline
- SSRIs
- CBT
What is coeliac disease?
Inflammation of the mucosa of the upper small bowel in response to gluten
Describe the epidemiology of coeliac disease
- ~1% of population in UK
- Any age, peaks in infancy and 40-60 years
- Familial link and risk
- HLA-DQ2 and HLA-DQ8 association
What are 2 risk factors for coeliac disease?
- Other autoimmune diseases
- IgA deficiency
Describe the pathophysiology of coeliac disease
- Autoimmune - T cell mediated
- Intolerance to prolamin (in wheat, barley, rye, oats - component of gluten protein)
- a-gliadin (type of prolamin) is resistant to digestion from protease enzymes (pepsin and chymotrypsin) in SI lumen
- This passes through damaged epithelial walls into cells
- Deaminated by transglutaminase
- Interacts with APCs and activate gluten-sensitive CD4+ T cells
- T cell produces pro inflammatory cytokines –> inflammatory cascade
- Causes villous atrophy and crypt hyperplasia
What are the autoantibodies present in majority of coeliac patients?
Anti-TTG and anti-EMA (attack enzymes that repair damage in the body)
What are 5 signs of coeliac disease?
- Malabsorption
- Steathorrhoea (increase in fat excretion in stools)
- Anaemia
- Failure to thrive (children)
- Osteomalacia
What are 9 symptoms of coeliac disease?
- Weight loss
- Fatigue and weakness
- Diarrhoea
- Abdominal pain
- Bloating
- Nausea/vomiting
- Aphthous ulcers
- Angular stomatitis
- Dermatitis herpetiformis (raised red patch of skin)
What is the first line investigation for patients with coeliac disease?
Serum antibody testing:
- IgA tissue transglutaminase (TTG)
- IgA anti-EMA
- Total IgA
- Very high sensitivity and specificity
What is the gold standard investigation for patients with coeliac disease?
Duodenal biopsy
- Endoscopically
- +ve findings = villous atrophy, crypt hyperplasia, increased epithelial WBCs
What are other investigations for coeliac disease?
- FBC (low Hb/folate/ferritin/B12)
- Genetic testing (HLA-DQ2 and HLA-DQ8)
- DEXA scan
What is the treatment for coeliac disease?
- Lifelong gluten-free diet (avoid foods containing wheat, barley, rye, oats)
- Correct vitamin deficiencies
- Pneumococcal vaccine given (hyposplenism)
What are 5 complications of coeliac disease?
- Anaemia
- Osteoporosis
- Hyposplenism
- Neuropathies
- Increased risk of malignancy
Which malignancies do patients with coeliac disease have a higher risk of?
- T cell lymphoma (increased T cells in GI wall)
- Gastric, oesophageal, small bowel, colorectal cancer (increased cell turnover)
What is gastritis?
Inflammation of the stomach’s mucosal lining
What are 6 causes of gastritis?
- H. Pylori infection
- Autoimmune gastritis
- Viruses
- Duodeno-gastro reflux
- NSAIDs
- Stress
Describe the pathophysiology of gastritis
- H. Pylori lives in the gastric mucus
- Secretes urease which splits urea in the stomach into CO2 and ammonia
- Ammonia + H+ = ammonium
- Ammonium, proteases, phospholipases and vacuolating cytotoxin A damages gastric epithelium
- This causes an inflammatory response reducing mucosal defence
- This also causes increased acid secretion
Describe the pathophysiology of autoimmune gastritis
- Affects the fundus and body of stomach
- This leads to atrophic gastritis and loss of parietal cells with intrinsic factor deficiency
- This results in pernicious anaemia
Describe the pathophysiology of gastritis due to aspirin/NSAIDs
- Aspirin/NSAIDs inhibit prostaglandins via the inhibition of cyclo-oxygenase
- This results in less mucus production
What is the difference between acute and chronic gastritis?
Acute = associated with neutrophilic infiltration
Chronic = associated with mononuclear cells (lymphocytes, plasma cells, macrophages)
What are 7 symptoms of gastritis?
Usually asymptomatic
1. Functional dyspepsia (indigestion)
2. Upper abdominal pain
3. Nausea and vomiting
4. Loss of appetite
5. Haematemesis
6. Abdominal bloating
7. Autoimmune pernicious anaemia
What are the investigations for patients with gastritis?
- Endoscopy
- Biopsy
- H. Pylori urea breath test
- H. Pylori stool antigen test
What is the treatment for gastritis?
- Eradication of H. Pylori (triple therapy):
- Clarithromycin
- Omeprazole
- Metronidazole
OR
H2 antagonists (to reduce acid release)
What is a complication of gastritis?
Peptic ulcer
What is gastro-oesophageal reflux disease (GORD)?
Prolonged or current reflux of the gastric contents through the lower oesophageal sphincter to the oesophagus
Describe the epidemiology of GORD
2-3 times more common in men
What are 5 causes of GORD?
- Complication of a hiatus hernia
- Smoking
- Alcoholism
- Obesity
- Pregnancy
Describe the pathophysiology of GORD
- Increase in transient lower oesophageal sphincter relaxations (due to reduced tone of LOS)
- This results in reflux of gastric contents (gastric acid, bile, pepsin etc.)
What is the normal epithelial lining of the oesophagus and stomach?
Oesophagus = squamous (sensitive to effects of stomach acid)
Stomach = columnar (more protected against stomach acid)
What are 6 symptoms of GORD?
- Heartburn (related to lying down and meals)
- Odynophagia (pain when swallowing)
- Acid regurgitation
- Nocturnal asthma
- Chronic cough
- Laryngitis, sinusitis
What are 2 investigations for patients with GORD?
- Endoscopy
- Barium swallow
What is the treatment for GORD?
- Smoking/alcohol cessation
- Weight loss
- Antacids
- Proton pump inhibitors e.g. omeprazole
- H2 receptor antagonist
- Surgery to tighten the lower oesophageal sphincter (laparoscopic fundoplication)
What are 2 complications of GORD?
- Oesophageal stricture formation (worsening dysphagia)
- Barrett’s oesophagus (can develop into oesophageal cancer)
What is Barrett’s oesophagus?
Normal squamous epithelium of distal oesophagus is replaced by abnormal columnar epithelium
What is the treatment for Barrett’s oesophagus?
- Proton pump inhibitors e.g. omeprazole
- Radiofrequency ablation (burn epithelial cells so they regenerate as normal stratified squamous cells)
What is a peptic ulcer?
Break in the gastric or duodenal mucosa in or adjacent to acid bearing area
Describe the epidemiology of peptic ulcers
Duodenal peptic ulcers are 2-3 times more common than gastric
What are 4 risk factors for gastric peptic ulcers?
- H. Pylori (80% association)
- Smoking
- Drugs
- Stress
What are 4 risk factors for duodenal peptic ulcers?
- H. Pylori (95% association)
- Smoking
- Drugs
- Alcohol
Describe the pathophysiology of peptic ulcers due to H. Pylori
- Increases gastric acid secretion
- Disrupts mucous protective layer
- Reduced duodenal bicarbonate production
- Leads to acidic contents of the stomach/duodenum breaking down the mucosa
Describe the pathophysiology of peptic ulcers due to NSAIDs
- Reduced production of prostaglandins (which provide mucosal protection)
- Leads to acidic contents of the stomach/duodenum breaking down the mucosa
What are 5 symptoms of peptic ulcers?
- Burning epigastric pain
- Nausea
- Heartburn
- Flatulence
- Occasionally painless haemorrhage
What is the difference in burning epigastric pain between people with gastric peptic ulcers and duodenal peptic ulcers?
Gastric = worse on eating, relieved by antacids
Duodenal = worse when hungry/at night, relieved by eating/milk
What are 3 investigations for patients with peptic ulcers?
- H. Pylori urea breath test
- H. Pylori stool antigen test
- Endoscopy
What is the treatment for peptic ulcers?
- Avoid NSAIDs
- Smoking cessation
- Eradication of H. Pylori (triple therapy):
- Clarithromycin
- Omeprazole
- Metronidazole
What are 4 complications of peptic ulcers?
- Upper GI bleed
- Haemorrhage
- Perforation
- Gastric outflow obstruction
What is a Mallory-Weiss Tear?
Mucosal lacerations in the upper GI tract causing bleeding/haematemesis
Describe the epidemiology of Mallory-Weiss Tears
- More common in males mainly between 20-50
- 4-8% of all upper gastrointestinal bleeding