Gastrointestinal Flashcards
What is malabsorption?
Failure to fully absorb nutrients, insufficient intake must be ruled out first.
What are the causes of malabsorption?
- Defective intraluminal digestion (pancreatic insufficiency, defective bile secretion).
- Insufficient absorptive area (coeliac + Crohn’s).
- Lack of digestive enzymes (lactose intolerance).
- Defective epithelial transport.
- Lymphatic obstruction (lymphoma, TB).
CROHN’S DISEASE (IBD)
What is the pathophysiology of Crohn’s?
A chronic inflammatory disease characterised by transmural granulomatous inflammation affecting any part of the GI tract from mouth to anus (esp. terminal ileum) with skip lesions (patchy).
CROHN’S DISEASE (IBD)
What does Crohn’s disease look like…
i) Macroscopically?
ii) Microscopically?
i) Skip lesions, cobblestone appearance, thickened + narrowed.
ii) Transmural, non-caseating granulomas, goblet cells present.
CROHN’S DISEASE (IBD)
What is the aetiology of Crohn’s disease? What are the associations of Crohn’s?
- An inappropriate immune response against gut flora in a genetically susceptible individual.
- Smoking (x3-4 risk), female, stress + depression (relapses), mutation on NOD2 gene, chromosome 16.
CROHN’S DISEASE (IBD)
What are the symptoms of Crohn’s disease?
Often associated with region…
- Small bowel = abdominal pain, weight loss.
- Terminal ileum - RIF pain mimicking appendicitis.
- Colonic = bloody diarrhoea, defecation pain.
CROHN’S DISEASE (IBD)
What are the signs of Crohn’s disease?
- Bowel ulceration.
- Abdominal tenderness/mass.
- Perianal abscess/fistulae/skin tags.
CROHN’S DISEASE (IBD)
What are the complications with Crohn’s disease?
- Malabsorption.
- Fistula.
- GI obstruction (fibrosis leading to contraction + subsequent obstruction).
- GI perforation.
- Anal fissures.
CROHN’S DISEASE (IBD)
What are the investigations for Crohn’s disease?
Bloods = FBC, U+E, LFTs, ESR/CRP.
Stool microscopy culture + sensitivity to rule out infection.
Colonoscopy + biopsy for histological examination.
CT enterography.
CROHN’S DISEASE (IBD)
What is the treatment for Crohn’s disease?
Lifestyle…
- Smoking cessation.
Corticosteroids like prednisolone induce remission.
Anti-TNF-alpha (adalimumab)
Methotexate to remain in remission.
Surgery if drug failure (resect affected areas).
ULCERATIVE COLITIS (IBD) What is the pathophysiology of ulcerative colitis?
- Ulcerative colitis is a relapsing + remitting inflammatory disorder of the colonic mucosa, originating in the anus + continuously progressing proximally but never to the ileocaecal valve.
ULCERATIVE COLITIS (IBD)
What does ulcerative colitis look like…
i) Macroscopically?
ii) Microscopically?
i) Continuous inflammation, ulcers, psuedo-polyps.
ii) Mucosal inflammation, no granuloma, depleted goblet cells, increased crypt abscesses.
ULCERATIVE COLITIS (IBD) What is the aetiology of ulcerative colitis?
- Inappropriate immune response against colonic flora in genetically susceptible individuals.
- UC is 3-fold as common in non-smokers + may relapse on smoking cessation.
ULCERATIVE COLITIS (IBD) What are the symptoms of ulcerative colitis?
- Episodic or recurrent diarrhoea (± blood or mucous).
- Crampy abdominal discomfort (LLQ).
- Bowel frequency relates to severity.
- Systemically = fever, malaise, weight loss.
ULCERATIVE COLITIS (IBD) What are the signs of ulcerative colitis?
- Tender, distended abdomen.
- Fever.
- Extra-intestinal signs = clubbing, erythema nodosum, ankylosing spondylitis.
ULCERATIVE COLITIS (IBD) What are the acute + chronic complications of ulcerative colitis?
Acute…
- Toxic dilatation of colon w/ risk of perforation, venous thromboembolism.
Chronic…
- Colonic cancer risk.
ULCERATIVE COLITIS (IBD) What are the investigations for ulcerative colitis?
Bloods = FBC, ESR/CRP, U+E, LFTs.
Stool microscopy culture + sensitivity to exclude infection.
Testing for pANCA antibody.
- Faecal calprotectin (non-invasive test for GI inflammation).
- CT abdomen.
- Flexible sigmoidoscopy + biopsy.
ULCERATIVE COLITIS (IBD) What are the treatments for ulcerative colitis?
Goals to induce then maintian disease remission.
- 5-aminosalicylic acid like mesalazine.
- Topical steroid foams.
- Colectomy if failed medical therapy.
IRRITABLE BOWEL SYNDROME
What is the pathophysiology of IBS?
- Relapsing functional bowel disorder associated with a change in bowel habit.
IRRITABLE BOWEL SYNDROME
What factors can contribute to IBS?
- Psychological morbidity like trauma in early life, stress.
- Abnormal gut motility.
- Genetics.
- Altered gut signalling (visceral hypersensitivity).
IRRITABLE BOWEL SYNDROME
What is the epidemiology of IBS?
- 10-20% prevalence, age at onset ≤40y/o, F:M ≥ 2:1
IRRITABLE BOWEL SYNDROME
What are the symptoms of IBS?
- Crampy abdominal pain.
- Pain relieved by defaction/wind.
- Altered stool form.
- Altered bowel frequency (constipation/diarrhoea may alternate).
IRRITABLE BOWEL SYNDROME
What are the differentials of IBS?
- Coeliac disease.
- IBD.
- Colorectal cancer.
- Lactos intolerance.
IRRITABLE BOWEL SYNDROME
What are the investigations for IBS?
Clinical…
- Recurrent abdominal pain with ≥2 symptoms.
- Symptoms chronic >6m
- Symptoms exacerbated by stress, menstruation or gastroenteritis.
Exclude other causes…
- Bloods – FBC, U+E, LFT, ESR/CRP.
- Coeliac serology.
IRRITABLE BOWEL SYNDROME
What is the should IBS treatment focus on?
- Focus on symptomatic control, lifestyle/dietary measures + then cognitive therapy if needed.
IRRITABLE BOWEL SYNDROME How can the following be treated in IBS... i) Constipation? ii) Diarrhoea? iii) Colic/bloating?
i) Adequate water + fibre, physical activity, laxatives or self-administered anal irrigation if needed.
ii) Avoid alcohol, caffeine, identify trigger foods, bulking agent ± anti-motility agent (loperamide) after each loose stool.
iii) Loperamide.
COELIAC DISEASE
What is the pathophysiology of coeliac disease?
- Gliadin is resistant to proteases in the small intestinal lumen + passes through a damaged epithelial barrier of the small intestine where it’s deaminated by tissue transglutaminase – increasing its immunogenicity.
- Gliadin then interacts with antigen-presenting cells (MHCII) in the lamina propria via HLA-DQ2+8, activates gluten-sensitive T cells.
- The resultant inflammatory cascade + release of mediators contribute to the villous atrophy + crypt hyperplasia.
COELIAC DISEASE
What is the toxic portion of gluten? What part of the GI tract is usually affected?
- Alpha gliadin.
- Duodenum
COELIAC DISEASE
What is the epidemiology of coeliac disease?
- Peaks in infancy + adults in fifth decade.
- 1 in 100.
- Relative risk in first degree relatives = x6
COELIAC DISEASE
What is the clinical presentation of coeliac disease?
- Diarrhoea.
- Weight loss.
- Abdominal pain.
- Bloating.
- Nausea + vomiting.
- Iron/B12/folate deficiency.
COELIAC DISEASE
What are the complications with coeliac disease?
Increased risk of malignancy (lymphoma, gastric, oesophageal)…
- Incidence may be reduced by gluten-free diet.
Hyposplenism…
- Offer flu + pneumococcal vaccine.
Osteoporosis.
COELIAC DISEASE
What are the investigations for coeliac disease?
Blood count…
- Mild anaemia, folate+iron deficiency may be present.
Serology, serum antibodies…
- Anti-transglutaminase + endomysial antibodies (IgA).
Endoscopy duodenal biopsy..
- While on gluten diet = subtotal villous atrophy, increased intra-epithelial WBCs, crypt hyperplasia.
COELIAC DISEASE
What is the treatment of coeliac disease?
Lifelong gluten-free diet + correction of any vitamin deficiencies.
GORD
What is the pathophysiology of gastro-oesophageal reflux disease (GORD)?
- Reflux of gastric acid, pepsin, bile + duodenal contents back into oesophagus.
- Transient lower oesophageal sphincter relaxation part of normal physiology but occur more frequent in patients with GORD allowing back-flow.
GORD
What is the aetiology of GORD?
- Male gender.
- Hiatus hernia.
- Oesophageal dysmotility.
- Obesity, pregnancy (increaed abdominal pressure).
- Smoking, alcohol.
GORD
What is the clinical presentation of GORD?
- Heartburn, belching, pain when swallowing, increased salivation.
- Chronic cough, nocturnal asthma (aspiration).
GORD
What are the complications with GORD?
- Oesophagitis.
- Ulcer.
- Barrett’s oesophagus (epithelium undergoes metaplasia from squamous to columnar epithelium + small amount progress to oesophageal cancer).
GORD
What are the investigations for GORD?
Clinical.
- Endoscopy, 24h oesophageal pH monitoring.
GORD
What is the lifestyle advice for GORD?
- Weight loss, smoking cessation, reduce hot drinks + alcohol, eat small regular meals, reduce citrus fruit, avoid eating <3h before bed.
GORD
What is the pharmacological treatment for GORD?
- Antacids like Gaviscon.
- PPIs like lansoprazole.
- H2 blockers like ranitidine.
- Avoid drugs affecting oesophageal motility (nitrates, anticholinergics) or that damage mucosa (NSAIDs, bisphosphonates).
OESOPHAGEAL CANCER
What is the distribution + type of oesophageal cancer
Distribution... - 20% upper, 50% middle, 30% lower. Type... - Squamous cell cancers proximal 2/3rds. - Adenocarcinomas distal 1/3rd.
OESOPHAGEAL CANCER
What are the aetiologies of oesophageal cancers?
Squamous cell carcinoma…
- Smoking, alcohol, poor diet.
Adenocarcinoma…
- Obesity, Barrett’s oesophagus.
OESOPHAGEAL CANCER
What is the clinical presentation for oesophageal cancer?
- Dysphagia.
- Weight loss.
- Heart burn.
- Signs from upper 1/3rd = hoarseness, cough.
OESOPHAGEAL CANCER
What are the investigations for oesophageal cancer?
- Oesophago-gastro-duodenoscopy (OGD) with biopsy.
- CT/MRI for staging.
OESOPHAGEAL CANCER
What is the treatment for oesophageal cancer?
- Surgical resection if possible.
- Chemo/radiotherapy if more advanced.
GASTRIC CANCER
What is the pathophysiology of gastric cancer?
- Tumours most commonly occur in the antrum + are almost always adenocarcinomas.
- They are localised ulcerated lesions with rolled edges or diffuse with extensive submucosal spread.
GASTRIC CANCER
What are the risk factors for gastric cancer?
- Helicobacter pylori x2
- Smoked foods, pickles.
- Gastritis + pernicious anaemia.
- Familial diffuse gastric cancer (mutation in CDH1).
GASTRIC CANCER
What are the symptoms of gastric cancer?
- Dyspepsia + dysphagia.
- Weight loss.
- Vomiting.
GASTRIC CANCER
What are the signs of gastric cancer?
- Epigastric mass.
- Hepatomegaly.
- Jaundice.
- Ascites.
GASTRIC CANCER
What are the investigations of gastric cancer?
- Gastroscopy with biopsy for diagnosis.
- CT/MRI for staging.
GASTRIC CANCER
What is the treatment of gastric cancer?
- Surgical resection (either full if early proximal or partial gastroscopy if early distal).
- Chemo/radiotherapy.
- B12 supplementation as reduced intrinsic factor.
COLORECTAL CANCER
What is the pathophysiology of colorectal cancer?
- Often occur sporadically, spread via direct invasion through bowel wall.
COLORECTAL CANCER
What is the aetiology + risk factors of colorectal cancer?
- Familial adenomatous polyposis.
- Hereditary nonpolyposis colorectal cancer.
- RF = red + processed meat, alcohol, smoking.