GI Flashcards
How does Loperamide work
Binds to the mu-opoid receptors ingut wall
Inhibits Ach & prostaglandin release
Decreases parasympathetic activity
What laxative do you give for opoid-induced constipation
Osmotic laxative (macrogol, laxido) + Senna
What laxatives should you avoid for opoid-induced constipation
Bulk forming laxatives (Ispaghulla husk, methylcellulose)
What medication should you avoid for diverticular disease
NSAIDs and antimotility drugs (loperamide, opoids)
Treatment for Diverticulosis
- Avoid anti-motility drugs - slowing down transit can lead to perforations
- Avoid NSAIDs
- Cramping? –> Anti-spasmodics {Mebeverine}
- Constipated? –> Bulk forming lax
- Plenty water
- 30g fibre/day
Diverticulitis treatment
Co-amoxiclav 500/125mg TDS for 5 days (or Cefalexin is allrgeic to penicillins)
What mediators cause Crohns Disease?
TH1 - IFNγ, TNF, IL-6
TH17- IL-17A/F, IL-21, IL-22
What mediators cause Ulerative collitis?
TH2 - IL-5, IL-6, IL-13, TNF
TH9 - IL-9
TH17 - IL17A/F, IL-21, IL-22
What mediators cause resolution in healthy cells?
IL-10, TGF-β
How does inflixumab work?
Human monoclonal antibodies that bind both soluble & trans membrane bioreactive forms of human TNFα -> prevents binding of TNFα to receptors -> –| biological activity of TNFα
What is the aim of UC therapy?
Reduce inflammation
Induce remission
maintain remission
Improve QOL
Minimise toxicity related to drugs
Maintain therapy used to maintain remission
What is the treatment for proctitis UC?
- Topical aminosalicylates
- Add oral aminosalicylate if remmision not achieved in 4 weeks
- For Pt that cannot tolerate aminosalicylates consider time limited oral/topical CC
What is the treatment for proctosigmoiditits & distal colitis UC?
- Topical aminosalicylates
- If remission not achieved in 4 weeks consider +high dose oral aminosalicylates
- if this still doesnt work then oral aminosalicylates + oral CC
What is the treatment for extensive UC?
- Topical aminosalicylates + high dose oral aminosalicylates
- no remission in 4 weeks then stop topical treatment & offer time limited course of oral CC
- For ppl who cannot tolerate aminosalicylates -> time limited oral CC
What are some aminosalicylate drugs
Mesalazine, Sulfasalazine
What should be monitored while on thiopurines?
FBC, U&E, LFT at least 2, 4 8 & 12 then 3 monthly
What should the PT report if they’re on thiopurines?
Ulceration
Fever
Infection
Bruising
Bleeding
What should you reduce the dose of azathioprine by when you are taking both allopurinol and azathioprine?
1/4
What is the treatment to induce remission is moderate to severe UC?
Biologics & JAK
Infliximab & adalinumab
What is the MOA of 5-aminosalcylates?
- Have an action on both PGD synthesi via cyclooxygenase and supression of pro-inflammatory cytokines
- Actions on supression of cytokines comes via –| of PPARgamma, NF.kB & other non-COX targets.
- Can also scavange reactive oxygen metabolites from superoxide anion generation by neutrophils which can in turn prevent DNA & tissue DMG.
What clinical features are unique to CD?
More debilitating that UC
Can be acute / insidious
Palpabke masses
Small bowel obstruction
Abcesses
Fistulas
What are the clinical features of both UC/CD?
- Diarrhoea
- Fever
- Abdominal pain
- N&V (More common in CD)
- Malaise
- Weight Loss (More common in CD)
- Malabsorption
Describe the pathophysiology of CD?
Can affect any part of the GUT
Usually terminal ileium & ascending colon.
Affected areas are thickened, deep ulcer can appear, can progress to deep fissuring uclers
What are the red flags & referral of IBS?
Unintentional weight loss
Unexplained rectal bleeding
Loose stool for >6weeks in Pt over 60 yrs
Anaemia
What medications should you stop taking while having diarrhoea for 24-48 hours?
ACE-i, ARB, Diuretics, Metformin.
What is the treatment of acute diarrhoea in adults?
Prevention & reversal of fluid & electrolyte depletion
Management of dehydration ]
ORT
Eat bland food
Stool bulking fruits
Avoid alcohol, caffeine
What drugs cause diarrhoea?
Antibiotics
Laxatives
Metformin
Ferrous sulphate
NSAIDs
Cholestyramine
Antacids
Digoxin
What is the MOA of diarrhoea which is caused by bacteria??
Invasive:
Directly attack mucosal cells which cause diarrhoea.
Stools may contain puss & blood.
Non-Invasive:
Do not DMG gut
Bacteria produce enterotoxins that disrupt secretions
What is chronic diarrhoea?
When its lasts more than 14 days
What is the pharmacology of stool softeners?
Emollient laxatives. Work as a surface wetting agent / surfactant. Decrease surface tension allows H20/Fat to penetrate stool.
What is the pharmacology of bulk forming laxatives?
- Mimic polysaccharides = increase osmolarity in the gut when broken
- Water retention = softening of stool
- Promotion of peristalsis via stimulating colonic mucosal receptors this leads to ACh release. ACh activates muscarinic ACh receptors which increases peristalsis
What is the treatment constipation in pregnancy/breastfeeding?
1 - Offer bulk forming
2 - ADD/Switch to osmotic
3 - Can consider a short course of stimulant
4 - Glycerol suppository.
Name some stimulant laxatives
Bisacodyl
Senna
Dentron
Sodium picosulphate
Name some faecal softeners
Docusate
Glycerol
Arachis oil
Name some osmotic laxatives
Lactulose
Macrogols
Mg
Name some bulking agents
Ispaghula husk
Methylcellulose
What treatments should be used for GORD?
Lifestyle & dietary changes
Alginate products / PPI
NOT H2 ANTAGONISTS.
What treatments should be used for dyspepsia, gastritis, PUD?
Removal of causative agents.
Dietary changes
Symptomatic treatment.
H2 antagonists/PPI
When should you refer someone to the GP when taking PPI?
After 2 weeks treatment there’s no improvement.
Treatment required continuously for 4 weeks then refer
Pt if over 45 & present with new or changed symptoms.
Weight loss, loss of appetite, signs of anaemia, dysphagia
What are the S/E of PPI?
Nausea, diarrhoea, flatulence, epigastric pain, dry mouth & headache.
What are PPI + MOA?
- Drugs that are enteric coated to be absorbed in the small intestine.
- Prolonged suppression of acid secretion.
- Heal uclers more rapidly than H2 antagonists.
- Superior treatment for reflux / GORD.
What are the S/E of H2 antagonists?
Headache & dizziness.
Cimetidine - Gyno 0.2%
Nizatidine - Sweating, abnormal dreams
Cimetidine binds to CYP450
What are H2 antagonists?
Class of drugs that compete for H2 receptors on the parietal cells.
Can be overridden by a powerful stimulus such as a large meal.
Alginates MOA
These come with antacids and form a high pH viscus mass (Raft) trapping air bubbles & CO2 from the reaction of antacid with stomach contents.
This raft floats to the top of the stomach and protects oesophageal mucosa from stomach contents.
How do you manage GORD?
Remove causative agents
Use of rafting products
Reduce acid prod to enable recovery of oesophageal mucosa.
How do you manage stomach & duodenal ulcers?
Identify & eradicate H.pylori
Stop inappropriate therapy
Decrease acid prod to reduce gastritis & enable mucosa to repair (H2 antagonist/ PPI)
What is a hiatus hernia?
Where part of the stomach is pushed up through the diaphragm, prevents LOS from closing, allowing stomach contents to escape.
What factors can cause the lowering pressure of the LOS?
Dietary factors
Smoking
Endocrine factors
Drugs
What are the symptoms of gastric ulcer?
Pain on eating, epigastric pain
What are the symptoms of Duodenal ulcer?
Localised pain occurring between meals and at night.
How is H.pylori identified?
Given radio labelled urea & CO2 produced in breath.
Stool sample needs to be stored at -20C before testing.
