case 11 - diarrhoea Flashcards
what is diarrhoea?
three or more loose or liquid stools per 24 hours
AND/OR
stools that are more frequent than what is normal for the individual lasting <14 days
AND/OR
stool weight greater than 200 g/day
what are the three classifications of diarrhoea?
acute (≤14 days)
persistent (>14 days)
chronic (>4 weeks)
what is acute diarrhoea?
lasting less than or equal to 14 days
what is persistent diarrhoea?
lasting longer than 14 days
what is chronic diarrhoea?
lasting longer than 4 weeks
how much fluid enters the GI tract every day?
approx 10 litres in one day
what are the constituents of the fluid that enters the GI tract every day?
ingested food and drink
secretions from salivary glands, stomach, pancreas, bile duct and duodenum
how much of the fluid entering the GI tract is reabsorbed and how much is excreted?
99% reabsorbed = 9.9 litres
1% excreted (in the faeces) = 0.1 litres
where does the majority of reabsorption take place in the GI tract?
small intestine
what happens in the GI tract as a result of diarrhoea?
reduced reabsorption of fluid
increased secretions of fluid and electrolytes
increased bowel motility
what are the two classifications of diarrhoea?
inflammatory and non-inflammatory diarrhoea
what are the classifications and sub-classifications of diarrhoea?
inflammatory and non-inflammatory
inflammatory = infectious OR non-infectious
non-inflammatory = secretory or osmotic
osmotic = malabsorption or maldigestion
what are some infectious causes of inflammatory diarrhoea?
bacterial, viral or parasitic infection
what are some non-infectious causes of inflammatory diarrhoea?
(inflammation due to) bowel ischaemia, radiation injury or inflammatory bowel disease
what symptoms does inflammatory diarrhoea present with?
mucoid or bloody stool
tenesmus
sever crampy abdominal pain
fever
define tenesmus
continual or recurrent inclination to empty the bowels
what is the most common cause of infectious inflammatory diarrhoea?
bacterial infection (Campylobacter, Salmonella, Shigella, E. coli C. difficile)
who is affected by viral inflammatory diarrhoea most commonly?
children who attend day care centres
who is affected by protozoa/parasitic inflammatory diarrhoea most commonly?
people in developing countries (get acute diarrhoea as a result)
what does infectious inflammatory diarrhoea usually look like?
small in volume, but frequent bowel movements
why does infectious inflammatory diarrhoea not usually result in volume depletion?
small in volume, but frequent bowel movements
can result in volume depletion in children/young adults
what will a stool test for infectious inflammatory diarrhoea show?
high leukocytes (but false-negatives common)
faecal occult blood
what does non-inflammatory diarrhoea look like?
watery, large volumes and frequent stool (10-20 per day)
why does non-inflammatory diarrhoea usually result in volume depletion?
usually larger volumes and watery so increased fluid loss