GI: Lower GI tract

Question 1

What is constipation?

Answer 1

• Reduced bowel movt (>3 a week)
• Can be due to low fibre in diet
• Drug induecd
  1. Opiods
  2. Tricyclic anti depressants
  3. Diuretics
  4. Anti-muscarinic drugs

Question 2

What are treatments for Constipation?

Answer 2

Laxatives
* Osmotic - Retain fluid in GIT to inc bulk and soften faeces
* Bulk - Inc vol of non-absorbable solid residue
* Stimulating purgatives - Inc GI smooth muscle to inc peristalsis

Drugs that alter GIT motility
* E.g. Doperidone
* Act on Pre-synp receptors to alter release of ACh
* Enhance peristalsis

Feacal softeners
* E.g. Docusate sodium
* Acts as detergent and stimulant laxative

Question 3

What is the Mucosal layer?

Answer 3

• Lining of GI tracts forms a protective mucosal layer
• Protaglandins promote secretion of mucous
• Bicarb ions secreted and ‘trapped’ in mucous mem
• Can be disrupted by:
  1. Gastritis, GERD, peptic ulcers
  2. Alcohol, spicy food etc

Question 4

What is IBS?

Answer 4

• Common, long term condition
• Inv pain and bloating (imp with defecation, cycles of dirrhoea and constipation)
• Treat with:
  1. Lactulose or loperamide to red symp
  2. Anti-spasmodic agents
  3. Mebeverine directly relaxes GI smooth muscle
  4. Low dose amitriptylines alter sensory nerves-pain release

Question 5

Explain IBS at a glance.

Answer 5

Question 6

What is Inflammatory bowel disease (IBD?

Answer 6

• Chronic inf
• Chron’s disease (terminal ileum and anus)
• Ulcerative colitis (large intestine)
• Give rise to pain and blood in stool
• Treat with anti-inf and immunosuppressants

Question 7

What are treatments fo IBD?

Answer 7

5-amonosalicyclates
* E.g. Sulpasalazine
* Release 5-aminosalicyclates (5-ASA)
* 5-ASA inhib leukotrine and prostanoid formation
* Scavenges free radicals and red neutrophil chemotaxins

Corticosteroids
* Anti-inf and immunosuppressive actions
* Budesonide is first choice-poorly absorbed so has less side effects

Immunosuppresants
* E.g. Methotrexate
* Infliximab is a MA for TNFa
* USed in severe chron’s disease

Question 8

What is bowel cancer?

Answer 8

Symptoms inc:
* Persistent blood in poo
* Persistent change in bowel habit
* Persistent lower abdominal pain, bloating or discomfort