Lower GI Flashcards
Ischaemic colitis
a) Risk factors
b) Radiographic appearance
c) Typical site
d) Management
a) Vascular disease, AF, cocaine (younger patients)
b) Thumbprinting
c) Splenic flexure - watershed area between IMA and SMA
d) Supportive - fluids, analgesia
- if becomes peritonitic –> resection
Food poisoning - likely pathogen
a) 2-4 hours after eating hamburger and salad
b) 1-4 days after eating undercooked meat
c) 1 day after eating pate or unpasteurised cheese
d) 12-72 hours after eating contaminated poultry, milk or eggs
e) 12 hours after eating meat left out or undercooked
a) S. aureus
b) Yersinia
c) Listeria enterocolitica
d) Salmonella enteritidis
e) Clostridium perfringens
Intestinal TB - characteristic feature on CT scan
Mesenteric thickening and lymph node enlargement
SIBO.
a) Define
b) Risk factors
c) Presentation
d) Diagnosis
e) Treatment
a) Excessive small intestinal bacteria
b) - Radiation enteritis is the main cause
- Small bowel surgery e.g. terminal ileal resection
- Diverticular disease
- PPIs
- IBS
c) IBS-like symptoms: bloating, diarrhoea, flatulence, weight loss, distension
d) - Hydrogen breath test
- Small intestinal secretion sample (e.g. ileostomy sample, jejunal aspirate)
e) - Elemental diet
- FODMAP diet
- Antibiotics e.g. metronidazole
Bile acid malabsorption*
a) Causes
b) Presentation
c) Diagnosis
d) Treatment
*AKA bile salt malabsorption
a) - Small bowel disease e.g. Crohn’s, terminal ileal resection, short bowel syndrome
- Drugs: metformin, colchicine
- Post-cholecystectomy
- Other GI diseases: pancreatitis, SIBO
b) Diarrhoea, malabsorption
c) SehCAT scan:
- Artificial bile acid, with isotope marker
- Drink, scan same day, then scan in 1 week, to see how much bile acid absorbed
d) - Remove cause (e.g. metformin)
- Cholestyramine
VIPoma
a) What is it ?
b) Presentation
c) Lab results
a) Vasoactive intestinal polypeptide secreting tumour
- A type of NET, usually pancreatic or small bowel
- Causes increased VIP release and hence increased cellular secretion in the bowel
b) Profuse watery diarrhoea, with significant electrolyte loss (usually hypokalaemia)
c) - Daily stool weight increased
- Serum VIP increased
IBS management
a) Initial management
b) IBS-C
c) IBS-D
d) Where medical management fails
a) - Dietary: e.g. low FODMAP/exclusion diets (refer dietitian), reduce caffeine, avoid sorbitol, altered fibre/fluid intake
- Anti-spasmodics - e.g. mebeverine, buscopan, peppermint oil
- Probiotics
- If the above fail, consider TCA or SSRI
b) - Increase fibre and fluids, add isphagula husk
- Laxatives (avoid lactulose as it increases gas production, which worsens symptoms)
- If laxatives fail for 12 months, consider linaclotide (GC-C agonist, stimulates intestinal secretions)
c) - Loperamide
- 5-HT3 agonists (-setrons) - alosetron and cilansetron (IBS specific, not antiemetics), or ondansetron, etc.
d) Psychological therapies
Rectal bleeding
a) Most common cause in elderly leading to haemodynamic instability
a) Diverticular disease
(rare for colorectal Ca or haemorrhoids to cause such severe bleeding)
RIF pain, fever, diarrhoea
CT AP shows “cluster of lymph nodes at appendix suggestive of mesenteric adenitis”
Yersinia infection
Colonoscopy surveillance for polyps
- Low risk (1-2 small adenomas <1cm): 5 year re-scope
- Moderate risk (3-4 small adenomas or at least one >1cm): 3 year re-scope
- High risk (5+ small adenomas or 3 bigger than 1cm): 1 year re-scope
Familial adenomatous polyposis
a) Gene and inheritance
b) Average age of polyps and of colorectal cancer if untreated
c) Other clinical features
d) Management
e) In general what is considered a positive family history of colorectal Ca?
a) APC on Ch5. AD inheritance
b) 16 polyps, 40 colorectal Ca
c) - Retinal pigment hypertrophy
- Dental- extra teeth, dental cysts
- Osteomas, fibromas, epidermoid cysts
d) - Regular colonoscopic surveillance
- Colectomy
- May also require OGD surveillance
e) 2 affected relatives or 1 under 45
Lynch syndrome (HNPCC)
a) Genes and inheritance
b) Cancers associated, frequency and age
c) Management
a) MMR genes, AD inheritance
b) Colorectal - age 45, 50% risk
Endometrial - 50% risk
Ovarian, stomach, small bowel, ureteric, biliary, skin, brain
c) Aspirin
Colonoscopy every 1-2 years from age 25
TVUS every year in women
Surgery where indicated
Inclusion bodies on colonoscopy biopsy
CMV colitis - usually in immunosuppressed patients including IBD on immunosuppressants
Melanosis coli
- appearance
- cause
Brown pigmentation on colonoscopy
Senna - absorbed by colonic mucosa causing apoptosis
Long-term PPI use, watery diarrhoea
Lymphocytic colitis - do colonoscopy + biopsy, and stop PPI
