What are the causes of hypernatremic dehydration in children?

Causes of Hypernatremic Dehydration in Children

Primary Etiologic Categories

Hypernatremic dehydration in children is predominantly caused by inadequate water intake (76% of cases), with gastroenteritis now accounting for only 20% of cases in hospitalized children, representing a major shift from historical patterns. 1

Iatrogenic and Hospital-Acquired Causes

The most common cause in modern pediatric practice is hospital-acquired hypernatremia (60% of cases), primarily from failure to provide adequate free water to vulnerable patients unable to care for themselves 1:

• Incorrect replacement of transepidermal water loss (TEWL) in very low birth weight infants is the leading iatrogenic cause 2, 3
• Excessive or inadvertent sodium administration during parenteral nutrition 2, 3
• Inadequate water intake during the transition phase in neonates and premature infants 3
• Inadequate fluid prescription in hospitalized patients is a common iatrogenic error 3

Gastrointestinal Losses

While historically dominant, gastroenteritis now contributes to only 20% of pediatric hypernatremia cases 1, though it remains the prominent cause in certain populations 4:

• Diarrhea (94.3% in some series, particularly in developing regions) 4
• Vomiting (25.9% reported history of refusal to feed or vomiting) 5
• High fecal output in patients with intestinal failure or short bowel syndrome 2

Feeding-Related Causes

• Improperly prepared infant formula, including concentrated formula (either to relieve constipation or due to confusion over spoon sizes) 6
• Use of artificial feeds is significantly associated with hypernatremia compared to breastfeeding 5
• Inadequate fluid intake in infants unable to communicate thirst 1

Renal and Metabolic Causes

• Excessive diuretic use, particularly in patients with liver disease 3
• Medications causing increased water loss (caffeine, diuretics in premature infants) 3
• Renal concentrating defects such as nephrogenic diabetes insipidus 3

Dermal Losses

• Excessive sweating in endurance athletes without adequate water replacement 3
• Severe burns resulting in voluminous fluid losses 3
• Transepidermal water loss especially in premature infants with immature skin barriers 3

High-Risk Populations

88% of children who develop hypernatremia have significant underlying medical problems 1:

• Neurologic impairment (unable to access water or communicate thirst) 1
• Critical illness requiring intensive care 1
• Chronic disease states 1
• Prematurity (particularly very low birth weight infants) 2, 1
• Well-nourished infants appear paradoxically at higher risk during gastroenteritis 5

Age Distribution

• Mean age is 3.9 years (range 1 day to 19.7 years), though infants predominate (61.4%) 1, 5
• Infants under 1 year with gastroenteritis represent the classic presentation, though this is becoming less common 1

Critical Clinical Pitfall

The vast majority of hypernatremia (71%) occurs in children admitted for reasons other than dehydration, meaning it develops as a complication during hospitalization rather than as a primary presenting problem 1. This underscores the importance of vigilant fluid management in all hospitalized children, particularly those with underlying vulnerabilities who cannot independently maintain adequate hydration.