GI 101 Diarrhoea Flashcards
Where are most fat soluble vitamins absorbed?
In the ileum
Where is vitamin B12 and bile acid absorbed?
The terminal ileum
What are the 4 histological layers of the gut?
Lumen out: Mucosa, submucosa, muscularis propria and serosa
What are the simple columnar epithelial cells in the gut and what feature do they have on their surface?
Enterocytes with microvilli
What cells are found in the muscosa of the GIT?
Surface -base: Enterocytes, goblet cells, endocrine cells, paneth cells and stem cells
What is the function of goblet cells?
Produce mucous
What is the function of paneth cells?
Gut defence: produce lysozymes and defensins
What are within the mucosa of the GIT contains capilliaries, nerves and lymphatics?
The lamina propria
What are the two layers of the muscularis propria in the GIT?
Inner circular smooth muscles, outer longitudinal smooth muscle
Where are Brunners Glands found and what do they do?
found in the proximal duodenum
secrete alkaline HCO3- and endocrine cells
Where are Peyers patches found and what is their function?
In the ileum submucosa and lamina propria - large lymphoid aggregates to sample gut contents
What is the definition of diarrhoea?
3 or more loose or watery stools (taking the shape of the container) in a 24 hour period
How long is acute and persistent diarrhoea?
Acute 14days
What is osmotic diarrhoea?
When there is a hypertonic substance in the lumen drawing water in
What are some of the causes of osmotic diarrhoea?
Ingestion of a non absorbable substance, generalise malabsorption or a specific absorptive defect
What is secretory diarrhoea?
When there is both intestinal secretion of fluid and decreased absorption = large volume diarrhoea
What are some of the causes of secretory diarrhoea?
enterotoxins, hormones, bile salts, fatty acids and some lazatives
What is inflammatory diarrhoea?
diarrhoea due to damage to intestinal mucosal cell resulting in loss of fluid/blood
What are some causes of inflammatory diarrhoea?
Some infective conditions and inflammatory bowel conditions
What is the leading cause of gastroenteritis in children?
Rotavirus
What is the most common virus causing diarrhoea in closed communities?
Norovirus
What is the 1st and 2nd most common cause of traveller’s diarrhoea?
ETEC - enterotoxigenic e.coli and campylobacter
What increases the risk of developing diarrhoea from Clostridium difficile?
abx use, hospital admission and PPI’s
What is the most common cause of parasitic diarrhoea in developed countries?
Giardiasis
How would you investigate diarrhoea?
Stool sample: culture and osmolality
Sigmoidoscopy/rectal biospy in persistent cases
How would you stop diarrhoea?
Loperamide or an opiod antagonist e.g. codeine
How would you treat diarrhoea?
Assess and treat any dehydration and address cause: abx, food intolerances
What is coeliac disease?
autoimmune disease against fluten resutling in inflammatory gut changes
What histological changes can be seen in coeliac disease?
atrophied villi, expanded and flattened mucosa
What are the symptoms of coeliac disease?
Steatorrhea, bloating, flatulence
