Severe dehydration in an 18-month-old at a basic health unit
A mother brings her 18-month-old boy to a rural basic health unit with a three-day history of watery diarrhoea and vomiting. He weighs 8 kg. He is lethargic, has sunken eyes, a skin pinch that takes three seconds to retract, a heart rate of 162/min, capillary refill of four seconds, and has passed no urine for 10 hours. The unit stocks oral rehydration salts, Ringer's lactate, intravenous cannulas and zinc tablets, but has no laboratory, no blood gas analyser and no paediatric intensive care. The nearest referral hospital is 90 minutes away. The child's mother is still breastfeeding him, and he is able to swallow. The medical officer must decide the rehydration route and fluid plan, and how to manage the risk of hypoglycaemia that cannot be measured.
1. Classify the dehydration and write the fluid plan you would start.
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This child has severe dehydration by WHO criteria: lethargy, sunken eyes, a skin pinch longer than two seconds, and no urine output. He needs Plan C, not oral rehydration alone, even though he can swallow.
Route: insert an IV cannula and give Ringer's lactate. The total volume is 100 mL/kg over 6 hours, but the schedule depends on age. At 18 months he is treated as 12 months or older:
- 30 mL/kg (240 mL) over 30 minutes, then
- 70 mL/kg (560 mL) over 2 hours 30 minutes.
Reassess after each bolus: if the radial pulse remains weak or the capillary refill stays prolonged, repeat 20-30 mL/kg. If IV access fails after three attempts, give oral rehydration solution by nasogastric tube at 20 mL/kg/hour for 6 hours.
Add zinc: 20 mg daily for 14 days. Zinc shortens the diarrhoea and reduces recurrence; it is not optional.
Continue breastfeeding throughout, and restart ORS as soon as he can drink. Do not give antibiotics unless there is blood in the stool, suspected cholera, or another specific indication. Antiemetics and antidiarrhoeals are not indicated and can cause harm.
2. How would you manage the risk of hypoglycaemia without a glucometer?
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In a lethargic child with poor intake and vomiting, assume hypoglycaemia until proven otherwise. The absence of a meter changes the threshold for action, not the principle.
Treat empirically if the child is lethargic, has a seizure, or deteriorates: give 10% dextrose 5 mL/kg (40 mL) IV over 2-5 minutes, followed by a maintenance infusion containing dextrose once circulation is restored. Do not wait for a laboratory result that is not available.
Prevent recurrence by continuing breastfeeding and starting ORS early, and by avoiding long gaps without glucose once the child is alert enough to feed. Recheck clinically after the bolus: improved tone, alertness and feeding are the available markers of response.
Escalate if lethargy persists after glucose and rehydration, or if seizures occur. Persistent lethargy after correction suggests another diagnosis such as meningitis, sepsis or severe electrolyte disturbance, and the 90-minute transfer becomes urgent. Document the empirical glucose dose and the response, because the receiving hospital will need that information.
3. What clinical signs would make you stop IV fluids and switch to ORS, and what are the dangers of continuing IV fluid too long?
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Switch when the signs of severe dehydration have resolved: the child is alert, eyes are no longer sunken, the skin pinch is under two seconds, capillary refill is under three seconds, and urine output has started. At that point give ORS 5 mL/kg/hour alongside continued breastfeeding and reassess hourly.
The dangers of continuing IV fluid are real in a setting without laboratory monitoring:
- Overhydration and pulmonary oedema, particularly if the child also receives repeated boluses without reassessment.
- Hypernatraemia or hyponatraemia from inappropriate fluid choice and poor monitoring.
- Missed ongoing losses: continuing diarrhoea and vomiting need replacement at 10 mL/kg for each loose stool, which IV fluid alone will not match.
The safe approach is to reassess after every bolus and at least hourly, and to treat IV fluid as a bridge to oral intake rather than the definitive treatment. Arrange referral if the child cannot tolerate ORS, has persistent vomiting, altered consciousness, or no urine after the initial rehydration phase.