Synopsis
Distinguish maintenance, deficit, replacement and resuscitation needs, prioritise oral rehydration, prescribe age-appropriate intravenous fluid and monitor electrolytes and clinical response safely.
- Separate four prescriptions: resuscitation restores circulation, deficit replaces prior loss, maintenance covers normal needs and replacement matches continuing abnormal loss.
- Assess dehydration from appearance, interaction, thirst, mucosa, tears, eyes, pulses, refill, breathing, urine and weight change; no single sign gives a reliable percentage.
- First-line for clinical dehydration from gastroenteritis without shock is low-osmolarity oral rehydration solution, 50 mL/kg deficit over 4 hours plus maintenance, given frequently in small amounts.
Key red flags
Reduced consciousness, weak pulses, cold mottled skin, markedly prolonged refill or hypotension indicates shock and invalidates routine oral rehydration alone.
Investigation priorities
Distinguish stable dehydration from shock and detect alternative emergencies.
Management branches
A child has dehydration without shock or another IV indication.
- Give low-osmolarity ORS 50 mL/kg over four hours plus maintenance in small frequent amounts and continue breastfeeding.
- Use nasogastric ORS if oral intake is insufficient or vomiting persists but the child remains suitable for enteral therapy.
A stable child cannot meet normal fluid needs enterally.
Key medicines
Low-osmolarity oral rehydration solutionFor clinical dehydration from gastroenteritis, give 50 mL/kg for deficit replacement over 4 hours plus maintenance fluid, in small frequent volumes; continue breastfeeding and use nasogastric administration if oral intake is insufficient and IV criteria are absent.
Isotonic crystalloid resuscitationGive 10 mL/kg of a glucose-free crystalloid containing 131–154 mmol/L sodium intravenously or intraosseously over less than 10 minutes for shock, then reassess before any further bolus; term neonates may require 10–20 mL/kg under neonatal guidance.