Lecture 8 - Diarrhoea and Constipation Flashcards
What is diarrhoea?
Increased liquidity of the stool and/or increased loose or liquid stool frequency (>3 times a day)
Classifications of diarrhoea?
acute (<14 days)
persistent (>14 days)
chronic (>30 days)
How many people a year suffer from one or more episodes of acute diarrhoea?
1 billion
What % of acute cases are caused by infectious agents?
90%
what are the two catagories of diarrhoea?
Inflammatory and non-inflammatory
What is inflammatory diarrhoea?
Presence of an inflammatory process (can be due to viral, bacterial or parasitic infection, radiation injury or inflammatory bowel disease
Symptoms of inflammatory diarrhoea?
mucoid and bloody stool, tenesmus, fever, crampy abdominal pain
small frequent bowel movements
Histology of GI tract in inflammatory diarrhoea?
abnormal
What is diarrhoea the main cause of?
death or disability in the world today
death is due to decreased blood volume
What is non-inflammatory diarrhoea?
watery, large volume frequent stool (>10 to 20 per day)
volume depletion is possible due to high volume and frequency of bowel movements
Symptoms of non-inflammatory diarrhoea?
No tenesmus, blood in the stool, fever or faecal leucocytes
Histology of GI tract in non-inflammatory diarrhoea?
Preserved
2 types of non-inflammatory diarrhoea?
Osmotic diarrhoea and secretory diarrhoea
Osmotic diarrhoea?
Presence of unabsorbed or poorly absorbed solute (eg Mg2+, mannitol and sortbitol - these promote water into the GI tract)
due to maldigestion or malabsorption
Stool volume of osmotic diarrhoea?
Small (compared to secretory diarrhoea)
Osmotic diarrhoea stops due to?
Stops or improves with fasting
Secretory diarrhoea?
altered transport of ions across the mucosa
increased secretion and decreased absorption of fluids
Secretory diarrhoea does not improve with?
Fasting
What is maldigestion?
when there is impaired digestion of nutrients in the GI lumen or the border of the mucosal epithelial cells
What is the most common cause of acute diarrhoea?
Infectious agents such as bacteria, viruses and parasites/protozoa
Bacteria causing diarrhoea?
E. coli, campylobacter, salmonella, C difficile, listeria, vibrio cholerae
E coli?
most common in developing countries, also a common cause of travellers diarrhoea
Campylobacter?
comes from contaminated poultry in developed countries
Salmonella?
ingestion of contaminated poultry (eggs and milk products)