Diarrhoea Flashcards
Which types of stools are categorised as diarrhoea on the bristol stool chart?
Type 5
Type 6
Type 7
What is diarrhoea?
A change in normal bowel habits that causes an increased frequency of bowel movements that produce soft and watery stool.
What is the difference between acute and chronic diarrhoea?
ACUTE:
- Abrupt onset of >3 stools per day
- Lasts no longer than 14 days
- often dietary causes
- Can be a result of bacterial or viral infection
- Usually restores in 2-3 days without treatment- just hydration and maybe hydration salts
CHRONIC:
- Has a pathological cause
- Lasts longer than 14 days
- Can be a flare up of a diagnosed condition e.g. IBS
- Requires further investigations
How many stools a day is classified as diarrhoea?
> 3
How long does acute diarrhoea typically last?
Usually restores within 2-3 days
but diarrhoea lasting less than 14 days is classified as acute diarrhoea
What age group is very common to get diarrhoea?
Under 5s
- often have 1-3 bouts per year
How many bouts of diarrhoea does the typical adult have per year?
1
- 22% is food related
- May be travellers diarrhoea
What is diarrhoea the second highest cause of?
Child mortality globally
What is the pathophysiology of diarrrhoea?
This is due to the changes in the balance between water and electrolytes absorption and secretion:
- Osmotic force drives water into the gut lumen e.g. after eating non-absorbable sugars e.g. mannitol or xylitol- if these sugars are avoided, diarrhoea stops
- Enterocytes (gut cells that line the gi tract) secrete fluid e.g. enterotoxin- induced diarrhoea- unlike above, this cant be avoided by stopping substance eating as it is caused by a pathogen
- Ion transporters are activated by bacteria pathogens- they invade enterocytes, causing the production of enterotoxins that damage cells, this increases cytokine secretion + increased prostaglandins = secretions
What is the difference between invasive bacteria, non-invasive bacteria and virus caused diarrhoea?
INVASIVE BACTERIA:
- cause a direct attack on the mucosal cells in the GIT
- The stools may contain blood and pus
- Often also causes a fever
- e.g. salmonella from badly cooked chicken, shigella, E.coli
NON-INVASIVE BACTERIA:
- These don’t directly damage the gut but instead produce enterotoxins that disrupt secretions the GIT causing watery stools
- e.g. saureus, enterotxigenic e.coli
Enterotoxin = a toxin produced in or affecting the intestines, such as those causing food poisoning or cholera
VIRALLY-INDUCED DIARRHOEA:
- The mechanism of action is not fully known
- The enterocytes become secretory = watery diarrhoea
What are the common causes of diarrhoea in the different age groups (infants, school children, adults, elders)?
INFANTS:
Infectious gasteroenteritis
Toddlers diarrhoea- hands in mouth, objects in mouth
Food intolerance
Coeliac disease
SCHOOL CHILDREN:
Infectious gasteroenteritis
Drugs e.g. antibiotics
ADULTS:
Infectious gastroenteritis
IBS, IBD
Drugs
Alcohol
Spicy foods
coeliac disease
ELDERLY:
Large bowel cancer
Faecal impaction
Drugs
Pseudo diarrhoea- watery stools spill over hard stools
Ischemic collitis
What are some microorganisms that cause diarrhoea with how long onset is?
Rotavirus- 12-48 hours
E.coli- 1-6 days
Shigella - 1-7 days
Salmonella - 12-24 hours
What are some drugs that can cause diarrhoea?
Antibiotics
laxatives
metformin
ferrous sulphate
NSAIDs
Cholestyramine
antacids
beta-blockers
digoxin
misoprolol
What are the treatment options for diarrhoea?
- Mostly oral rehydration therapy e.g. Dioralyte
- Rapid control = loperamide (opioid agonist that decreases gut motility)
What is the OTC dose of loperamide?
Initially, 4mg, followed by 2mg after each loose stool.
Usual daily dose = 6-8 mg and max daily dose = 12mg
Up to 48 hours only