Acute Diarrhoea ✅ Flashcards
What is the role of the gut?
- Maintain fluid homeostasis
- Allow absorption of dietary nutrients
How does the gut maintain fluid homeostasis?
Through absorption or secretion
What is the importance of allowing absorption of dietary nutrients?
Allow growth, repair, and maintain normal functions of the body
What happens when fluid homeostasis is not maintained by the gut?
Diarrhoea results
What is the result of the gut always absorbing nutrients to its maximal ability?
If calorie intake exceeds energy expenditure, obesity results
What is diarrhoea defined as?
The rapid transit of gastric contents through the bowel
How often do children open their bowels?
Frequency variable in childhood, but median is 1 bowel movement per day
What is considered to be diarrhoea in terms of bowel movements?
3 or more loose watery stools per day
What can protracted diarrhoea lead to?
Severe malnutrition
What can severe malnutrition caused by protracted diarrhoea lead to?
Prolonged impairment of physical and intellectual development
When in particular does malnutrition caused by diarrhoea have the potential to cause impairment of development?
When it occurs at a vulnerable period of brain development
At what age are episodes of acute diarrhoea most common?
In the first year of life
What is the problem with acute diarrhoea being most common in the first year of life?
- Brain development is incomplete
- Wide variety of intestinal transport mechanisms which are concerned with absorption and secretion of fluid are poorly developed
What can diarrhoea be categorised as?
- Osmotic
- Secretory
What is the problem in osmotic diarrhoea?
Excess osmotically active particles in the gut lumen
Why does excess osmotically active particles in the gut lumen lead to diarrhoea?
More fluid passively moves into the bowel lumen down the osmotic gradient, which may exceed the absorptive capacity of the gut and lead to diarrhoea
What happens in osmotic diarrhoea if the child is not fed?
The diarrhoea stops
What are the causes of osmotic diarrhoea?
- Ingestion of solutes which cannot be absorbed
- Malabsorption of specific solutes
- Damage to absorptive area of mucosa, resulting in less fluid absorption
- Motility disorders
Give an example of a solute that cannot be absorbed
Osmotic laxatives such as lactulose
Give 2 examples of causes of malabsorption of specific solutes
- Disaccharide deficiency
- Glucose-galactose malabsorption
Give 4 causes of damage to the absorptive area of the mucosa
- Gastroenteritis
- CMPA
- Coeliac disease
- Crohn’s disease
Give 3 examples of motility disorders
- Gastroschisis
- IBS
- Hyperthyroidism
Why can motility disorders lead to osmotic diarrhoea?
Can result in reduced contact with bowel lumen, therefore higher concentration of solutes within the lumen
What is the problem in secretory diarrhoea?
Bowel mucosa secretes excessive amounts of fluid
What are the causes of secretory diarrhoea?
- Activation of specific pathway by a toxin
- Inherent abnormalities in the enterocytes
Give an example of a toxin causing secretory diarrhoea
Cholera toxin
Give an example of an inherent abnormality causing secretory diarrhoea
Congenital microvillous atrophy
Are absorptive mechanisms present in secretory diarrhoea?
They are often still present, but overwhelmed
Does secretory diarrhoea stop if feeds are withheld?
No
Can osmotic and secretory diarrhoea occur together?
Yes
Can osmotic and secretory diarrhoea occur in acute and chronic disease?
Yes