Session 13 - Shitting 'n Sickness Flashcards
What is management of peptic ulcer if due to h.pylori
PPI (omeprazole)
Antibiotics (Clarithromycin/amoxicillin)
H2 antagonist - Cimetidine
What are four defensive aspects of the gastric mucosa
Epithelial integrity
Cell replication and restitution
Mucous membrane barrier
Vascular supply
What are the three main agressive factors of the gastric mucosa
Acid
H. Pylori
Drugs (NSAIDs)
Outline the phases of control of gastric secretion
Cephalic
- Sensory stimulus and act of swallowing stimulates Ach release, stimulating parietal cells
Gastric
- Distension, further stimulating Ach release
- Buffering of stomach acid stimulates gastrin release
- Small peptides cause upregulation of gastrin
Intestinal
- CCK and GIP released once chyme enters duodenum, which inhibit gastrin.
- Low pH also inhibits gastrin
Outline the plexi of the enteric nervous system (four), including where they can be found
o Auerbach’s Plexus Between circular and longitudinal muscle layers o Meissner’s Plexus Submucosa o Henle’s Plexus Circular muscle adjacent to submucosa o Cajal’s Plexus Circular muscle adjacent to longitudinal muscle
How do the plexi control the GI tract?
Together these autonomic gonglionated plexi control the functioning of the GI tract through complex local reflex connections between sensory neurones, smooth muscle, mucosa and blood vessels.
Extrinsic parasympathetic fibres from the vagus are excitatory, extrinsic sympathetic fibres are inhibitory.
What are the three main reflexes of the GI tract
o Intestino-intestinal inhibitory reflex
Distension of one intestinal segment causes complete intestinal inhibition (Peristalsis)
o Anointestinal Inhibitory Reflex
Distension of anus causes intestinal inhibition
o Gastrocolic and Duodenocolic Reflexes
Stimulates motility after material has entered the stomach or duodenum
What are laxatives used for?
To hasten transit time in the gut and encourage defecation. Laxatives are used to relieve constipation and to clear the bowel prior to medical and surgical procedures.
What is the best regulator of frequency and volume of stool?
Diet
What are four different types of laxatives?
o Bulk Laxatives
o Faecal Softeners
o Osmotic Laxatives
o Irritant / Stimulant Laxatives
What would you give in soft faeces constipation
Stimulant laxatives
What would you give in history or DRE hard faeces
Osmotic laxatives
Bulk-forming laxatives
What is the indication for a bulk laxative?
Constipation, particularly when hard stools are present
What are four contraindications for bulk laxatives?
Dysphagia
Intestinal obstruction (Adhesions, ulceration)
Colonic atony
Faecal impaction
What is the mechanism of action for bulk laxatives?
Increases the volume of the non-absorbable solid residue in the gut, distending the colon and stimulating peristaltic movement.
Give three ADRs of bulk laxatives
Flatulence
Abdominal distension
GI obstruction
What is necessary for the patient to do while taking bulk laxatives?
Have a normal fluid intake
Give a type of faecal softener
Glycerol (given as suppository
Give four indications for faecal softeners
Constipation
Faecal impaction
Haemorrhoids
Anal fissures
What group should faecal softeners not be used on/
Children less than 3
What is the mech of action of faecal softeners?
Lubricate and softens stools
What is the mechanism of action of an osmotic laxative?
Increase water content of the bowel via osmosis
Lactulose – Disaccharide (galactose/fructose) that cannot be hydrolysed by digestive enzymes. The fermentation of lactulose by colonic bacteria gives acetic and lactic acid. This has an osmotic effect
Name an osmotic laxative
Lactulose
What are the indications for osmotic laxatives?
Constipation
Lactulose - Liver failure (reduced production of ammonia)