Clinical features, stages, characteristic laboratory values and treatment of dehydration.

1. Big picture

Dehydration in pediatrics is a loss of body water with or without electrolyte disturbance, most commonly due to acute gastroenteritis.

It is high-yield because infants and young children decompensate quickly:

Vomiting / diarrhea / fever / poor intake
→ fluid loss
→ extracellular volume depletion
→ tachycardia + poor perfusion
→ shock
→ acute kidney injury, acidosis, electrolyte disturbance
→ death if untreated

For the exam, think in three steps:

1. How severe is the dehydration?
2. What type is it by sodium level?
3. Can I rehydrate orally, or does this child need IV emergency fluids?

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