Signs and Symptoms of Severe Dehydration in Children
Severe dehydration (≥10% fluid deficit) in children presents with severe lethargy or altered consciousness, prolonged skin tenting >2 seconds, cool and poorly perfused extremities with decreased capillary refill, and rapid deep breathing indicating metabolic acidosis. 1
Critical Clinical Features
Neurological Signs
- Severe lethargy or altered state of consciousness is a hallmark feature that distinguishes severe from moderate dehydration 1
- Mental status changes indicate significant fluid deficit requiring immediate intervention 1
Skin and Perfusion Signs
- Prolonged skin tenting and skin retraction time >2 seconds when skin is pinched 1
- Cool and poorly perfused extremities with decreased capillary refill 1
- Capillary refill time correlates well with fluid deficit and is one of the most reliable predictors of dehydration severity 1, 2
Respiratory Signs
- Rapid, deep breathing (Kussmaul respirations) indicating metabolic acidosis 1
- This respiratory pattern is more reliably predictive of severe dehydration than sunken fontanelle or absence of tears 1
Cardiovascular Signs
- Shock or near-shock state with compromised pulse and perfusion 1
- Decreased pulse quality and abnormal vital signs 2
Most Reliable Clinical Indicators
The CDC guidelines emphasize that prolonged skin retraction time, decreased perfusion, and rapid deep breathing are more reliably predictive of severe dehydration than commonly cited signs like sunken fontanelle or absence of tears 1. Capillary refill time shows good correlation with fluid deficit, though fever, ambient temperature, and age can affect this measurement 1.
Critical Management Implication
Severe dehydration constitutes a medical emergency requiring immediate IV rehydration with 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 1, 2. This may require two IV lines or alternate access sites such as venous cutdown, femoral vein, or intraosseous infusion 1.
Common Pitfalls to Avoid
- Do not rely solely on sunken fontanelle or absent tears for assessing severe dehydration, as these are less reliable indicators 1, 2
- Do not delay IV access in children with altered mental status, poor perfusion, or signs of shock 1
- Fever, ambient temperature, and age can affect capillary refill time interpretation, so consider these factors in your assessment 1
Additional Assessment Considerations
While the most accurate assessment of fluid status is acute weight change, premorbid weight is often unknown 1. Body weight should be measured immediately upon presentation to establish baseline and calculate fluid deficit 1, 2. Infants are at particular risk for rapid dehydration due to higher body surface-to-weight ratio, higher metabolic rate, and dependence on others for fluid 1.