GI Tutorial. General Structure Mucosa –Epithelium –Lamina Propria –Muscularis Mucosa Submucosa...
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Transcript of GI Tutorial. General Structure Mucosa –Epithelium –Lamina Propria –Muscularis Mucosa Submucosa...
GI Tutorial
General Structure
• Mucosa– Epithelium– Lamina Propria– Muscularis Mucosa
• Submucosa– Connective tissue, blood vessels, nerve plexus
• Muscularis propria• Serosa & subserosa
– Fat, connective tissue, blood vessels– Lined by peritoneum in areas
Structure and Function
• Tubular structure– Complications:
• Bleed – Haemorrhage• Burst – Perforation• Block – Obstruction• Fistula formation
• Digestive and Absorptive function– Complications
• Malabsorption– Total– Specific: Vit B12, fatty acids, proteins
• Diarrhoea
GI Tumours• Tumour structure
– Exophytic = nodule / polyp– Diffuse infiltrative = spread thru wall +/- stricture– Endophytic = ulcer / excavation
• Microscopy– Adenocarcinoma
• Signet ring carcinoma (stomach), typical adenoca (all areas)
– Squamous cell carcinoma• Oesophagus, Anus, Pharynx, Oral Cavity
– Rarer tumours• Carcinoid (anywhere, commonly appendix)• Sarcoma (leiomyosarcoma / gastrointestinal stromal tumour)• Lymphoma• Melanoma (oesophagus)
GI Tumours
• Pathogenesis = enviromental & host factors– Enviromental factors
• Drugs– Smoking
– Alcohol
• Diet– Nitrosamines, Vit deficiency (Oesophagus)
– Preservatives, Lack of fresh fruit/veg (Stomach)
– Excess intake/red meat/refined carbs, low fibre (Colon)
GI Tumours
• Pathogenesis = enviromental & host factors– Host factors
• Predisposing inherited conditions– FAP, Gardner syndrome, HNPCC (Colon ca)
• Predisposing inflammatory conditions– Barretts oesophagus (oesophagus)– Autoimmune / HLO gastritis (stomach)– Coeliac disease (SI)– Ulcerative colitis (colon)
• Family history (especially colon ca)
Approach to GI Tumour Questions
• Epidemiology– Male / female, age, race, geographic distribution
• Pathogenesis– enviromental: drugs, diet, other
– host: inherited / inflammatory conditions, family hx
– Sequence of events:• Inflammation metaplasia dysplasia invasion
• Sequence of mutations (adenoma carcinoma sequence in colon)
Approach to GI Tumour Questions
• Morphology– Gross:
• Location– Upper/mid/distal oesophagus, pylorus/cardia/fundus, duodenum/
ampulla/jejunum/ileum, caecum/asc/trans/des/sigmoid/rectum
• Appearance– Exophytic, infiltrative, endophytic
– Microscopy• Adenocarcinoma (+/- signet ring), squamous, other
– Spread• Local lymph nodes, liver, lungs, ovaries
Approach to GI Tumour Questions
• Clinical– Presentation
• Weight loss, anorexia, altered bowel habit, pain• Obstruction
– dysphagia, vomiting, abdo distension with constipation• GI haemorrhage – chronic : anaemia
– acute: haemoptysis, meleana, collapse
• Metastatic disease – hepatomegaly, ascites, lung lesions
– Prognosis / Staging– Complications:
• Haemorrhage, Perforation, Obstruction, Fistula formation• Local spread: compression/invasion of adjacent organs• Distant mets
SI obstruction