Neonatal Hypernatremia
Neonatal Hypernatremia
Neonatal hypernatremia is defined as serum sodium concentration >145 mEq/L in newborns. It's a serious condition that can lead to significant morbidity if not recognized and treated appropriately.
Key Points
- Critical threshold: Severe hypernatremia is defined as >160 mEq/L
- Most common in exclusively breastfed newborns
- Associated with significant dehydration
- Requires gradual correction to prevent neurological complications
- Prevention through early feeding support is crucial
Definition & Epidemiology
Classification
- Mild: 146-149 mEq/L
- Moderate: 150-159 mEq/L
- Severe: ≥160 mEq/L
Epidemiology
- Incidence:
- 1-2% of all newborns
- Up to 10% in exclusively breastfed infants
- Risk Factors:
- First-time mothers
- Delayed lactation
- Poor breastfeeding technique
- Maternal breast surgery
- Cesarean delivery
- Prematurity
- Environmental factors (high temperature)
Pathophysiology
Mechanisms
- Primary causes:
- Free water deficit (most common)
- Inadequate breast milk intake
- Excessive water losses
- High environmental temperature
- Sodium excess
- Iatrogenic sodium administration
- Salt poisoning
- Concentrated formula preparation
- Free water deficit (most common)
Pathophysiological Changes
- Cellular effects:
- Cell shrinkage due to osmotic water shift
- Brain cell adaptation through organic osmolyte accumulation
- Risk of vessel rupture during rapid correction
- Systemic effects:
- Intravascular volume depletion
- Decreased tissue perfusion
- Risk of thrombosis
Diagnosis & Clinical Features
Clinical Presentation
- Early signs:
- Poor feeding
- Lethargy
- Decreased urine output
- Weight loss >10% of birth weight
- Advanced signs:
- Irritability
- High-pitched cry
- Hyperthermia
- Seizures
- Bleeding tendency
- Physical examination findings:
- Skin tenting
- Dry mucous membranes
- Sunken fontanelle
- Jaundice
Diagnostic Workup
- Essential laboratory tests:
- Serum electrolytes
- Blood urea nitrogen
- Creatinine
- Serum osmolality
- Blood glucose
- Acid-base status
- Additional tests:
- Coagulation profile
- Calcium levels
- Brain imaging if neurological symptoms
Management
Initial Assessment
- Calculate free water deficit
- Determine rate of sodium elevation
- Assess volume status
- Evaluate for complications
Treatment Principles
- Correction rate:
- Maximum decrease: 0.5 mEq/L/hour
- Target: 10-12 mEq/L/24 hours
- Total correction time: 48-72 hours
- Fluid management:
- Calculate deficit + maintenance
- Choice of fluid: 0.9% or 0.45% NaCl based on volume status
- Frequent monitoring of serum sodium (every 4-6 hours)
Calculations
Free Water Deficit = Current TBW × [(Current Na/Desired Na) - 1]
- TBW (Total Body Water):
- Term newborns: 0.6 × weight in kg
- Preterm newborns: 0.7-0.8 × weight in kg
Complications & Prevention
Acute Complications
- Neurological:
- Cerebral hemorrhage
- Venous thrombosis
- Permanent neurological damage
- Seizures
- Other complications:
- Acute kidney injury
- DIC
- Death
Prevention Strategies
- Feeding support:
- Early lactation support
- Regular feeding assessment
- Weight monitoring
- Parent education:
- Recognition of feeding cues
- Signs of adequate intake
- Warning signs for dehydration
- Healthcare provider vigilance:
- Regular newborn follow-up
- Early weight checks
- Prompt intervention for feeding difficulties
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
