Diarrhoea & Dehydration in Children

Question 1

What is the medical definition of diarrhoea? How do we define it in breast-fed infants?

Answer 1

• Passage of loose/watery stools at least 3 times in 24 hours.
• In breast-fed infants, we identify it by sudden increase in frequecy/changes in consistency of stools

Question 2

What is the commonest cause of acute diarrhoea in children and infants? What is the timeframe of acute diarrhoea?

Answer 2

• Acute is less than 14 days (any longer is chronic)
• Commonest cause is enteral infection (gastroenteritis)

Question 3

Outline the four broad types/features of diarrhoea?

Answer 3

• Osmotic: substances in the gut (e.g. poorly absorbed lactose in Cameron Chau) draw water into the lumen [stops with no oral intake]
• Secretory: active secretion of water and ions (e.g. cholera toxin acts on CFTR in the gut, causing Cl- and water loss) [keeps going with no oral intake]
• Inflammatory: autoimmune/infective causes lead to increased intestinal permeability + exudation + less absorption (often contains mucous and/or blood)
• Motility-related: high gut motility affects absorption

Question 4

List viruses that can cause diarrhoea in children (+ which is most common?)

Answer 4

• Most common is rotavirus
• Others include astrovirus, adenovirus, enterovirus, norovirus

Question 5

List bacteria that can cause diarrhoea in children

Answer 5

• Salmonella
• Shigella
• Campylobacter
• E Coli
• Cholera

Question 6

List parasite that can cause diarrhoea in children

Answer 6

• Giardia
• Cryptosporidium
• Entamoeba

Question 7

Characteristics of bacterial/viral/parasitic diarrhoea

Answer 7

• Viral more likely watery stools
• Bacterial more likely bloody stools
• Parasitic more likely longer disease course

Question 8

Downstream consequences of diarrhoea in children/infants. How does this differ with vomiting?

Answer 8

• Dehydration (can be mild, or more severe, causing electrolyte disturbances and metabolic acidosis)
• In vomiting, we lose stomach acid rather than bicarbonate-rich colon secretions, so we get metabolic alkalosis instead

Question 9

Complications of diarrhoea in children/infants (including the two kinds of complications)

Answer 9

• Instestinal (more common in bacterial): persistent diarrhoea, toxic megacolon, perforation, rectal prolapse
• Extraintestinal: dehydration, electrolyte disturbances, bacteraemia

Question 10

What are some causes of chronic diarrhoea in children?

Answer 10

• Inflammatory bowel disease
• Coeliac disease
• Food allergies