Lower GI tract disorders Flashcards
What arteries supply the large intestine/colon?
branches of superior and inferior mesenteric arteries
What are the layers of the colon wall?
- mucosa: epithelium, lamina propria, muscularis mucosae
- submucosa: glands here produce mucin (lubricates bowel)
- muscularis: circular adn longitudinal muscle
- serosa: connective tissue and nerve supply
What is the nerve supply to the colon?
- parasympathetic: ascending and most of transverse colon innervated by vagus nerve–> more distally innervated by pelvic nerves
- sympathetic: lower thoracic and upper lumbar spinal cord
- external anal sphincter controlled by somatic (voluntary) motor fibres in the pudendal nerves
How can we divide lower GI tract disorders into 6 categories?
- inflammatory: IBD, miscrosopic colitis (normal looking mucosa in colonoscopy, but histological abnormalities)
- infective: C diff, E coli etc…
- structural: diverticular disease, haemorrhoids, fissures
- functional: irritable bowel syndrome (normal investigations, but significant symptoms)
- neoplastic: colonic polyps + colon cancer
- other: neurological, metabolic + vascular
What is inflammatory bowel disease?
- lifelong chronic disease, often affecting young people
- comprises ulcerative colitis and Crohn’s disease
- takes major toll on patients and healthcare
What is ulcerative colitis?
- inflammation limited to colonic mucosa- mainly superficial layer
- continuous inflammation
- always involves rectum
- M=F incidence
- no granulomas
What is Crohn’s disease?
- can affect any part of GI tract
- patchy in nature e.g. part of colon, part of small bowel
- deeper inflammation- doesn’t just affect mucosa–> transmural
- granulomatous inflammation
- tendency to form fistulas (communication btwn diff. walls of bowel) and strictures (narrowing of lumen due to fibrous tissue)
- F>M (1.5: 1)
What is proctitis?
UC that only involves rectum
What is proctosigmoiditis?
UC that involves sigmoid colon and rectum
What is distal colitis?
UC that extends up through descending colon
What is extensive colitis?
UC that extends through to the transverse colon
What is pancolitis?
UC that involves the whole of the colon and rectum
What symptoms are associated with colitis?
- bleeding
- mucus
- urgency (hallmark of lower rectal disorder)
- diarrhoea
What symptoms are associated with perianal Crohns disease?
- anal pain (Crohns- pain bc deeper ulcers)
- leakage
- difficulty passing stool
What symptoms are associated with small bowel Crohns disease?
- abdominal pain
- weight loss (bc less absorption)
- tiredness/lethargy (bc less absorption of vitamins)
- diarrhoea
- abdominal masses
