Introduction
Diarrhoea means passing loose or watery stools three or more times in 24 hours (or more often than usual for that child; breastfed babies normally pass soft, frequent stools). It is acute when it lasts under 14 days (usually under 7), persistent at 14 days or more, and chronic beyond 4 weeks. Worldwide, diarrhoea still kills about half a million children a year, mostly from dehydration.
How dehydrated is the child?
The three most useful signs are prolonged capillary refill, reduced skin turgor and deep (acidotic) breathing. Weight loss is the gold standard if a recent weight is known.
Treatment
- Oral rehydration solution (ORS), low-osmolarity (sodium 60–75 mmol/L): 50–100 mL/kg over 3–4 hours for some dehydration, in small frequent sips (a spoon or syringe every minute if vomiting). Plus about 10 mL/kg after each loose stool (and 2 mL/kg after each vomit).
- If oral fails: the same by nasogastric tube.
- Shock: IV 0.9% saline 20 mL/kg boluses, then IV rehydration over 24 hours; check sodium, potassium, glucose, creatinine.
- Keep feeding: continue breastfeeding; normal diet as soon as rehydrated. No sugary drinks or fruit juice (they worsen diarrhoea).
- Zinc for 10–14 days (WHO, in low-income settings): shorter and fewer episodes. Probiotics (Lactobacillus rhamnosus GG, Saccharomyces boulardii) and racecadotril can shorten diarrhoea; ondansetron (single dose) helps a vomiting child keep ORS down.
- Antibiotics only for Shigella, cholera, Giardia, amoebiasis, severe Campylobacter or Salmonella in infants or the immunocompromised, and C. difficile. Loperamide is not for young children.
Hypernatraemic dehydration (sodium over 150 mmol/L): skin feels doughy, the child is very irritable, and dehydration is underestimated. Rehydrate slowly over 48 hours, lowering sodium by no more than about 10–12 mmol/L a day, or brain oedema and seizures follow.