Hypernatremia in neonates is potentially lethal and can cause neurological damage. It is commonly caused by water loss exceeding sodium loss due to greater insensible losses and inability of neonates to communicate thirst. Treatment involves stabilizing the infant, determining the rapidity and rate of sodium correction to avoid cerebral edema, and rehydrating over 2-3 days with IV saline and dextrose solutions to slowly lower the serum sodium level.

1. Hypernatremia in Neonates
Khazaei , MD
Associate Professor, Pediatric Nephrologist
Islamic Azad University – Masshad Branch

2. Importance of hypernatremia dehydration
 a potentially lethal condition
 neonates are vulnerable to hypernatremia due to:
 greater insensible losses
 inability to communicate their need for fluids or access
fluids independently
 Moderate to severe hypernatremia can cause
neurological manifestation and damage

3. SerumNa+(mEq/L)
definition
< 135
Hyponatremia
135-145
Normal
146-149
Mild hypernatremia
150-169
Moderate hypernatremia
> 170
Severe hypernatremia

4. Neonatal HN: Causes
 Water loss in excess of sodium (more common):
 Poor feeding in the early days of life
 Increased insensible water losses through:
 an immature, water-permeable stratum corneum, (phototherapy, warmer!!)
 unproportional increased BSA,
 increased resp. rate
 Improper clothing (63.5% in fall & winter season)(Sanaei Z. Iranian Journal of Neonatology.
2017 Sep)
 Breast milk with high Na content (see next Slide)
 Immature renal function regarding U. concentration ability.
 Rare causes:
 central or nephrogenic diabetes insipidus.
 CAH
 Hyperaldostronism ( Con’s disease)
 Solute overload (rare):
 Adding too much salt when preparing homemade infant formula
 Hyperosmolar solutions. Fresh frozen plasma and human albumin

5. Breast milk sodium
 The sodium content of breast milk at birth is high and
declines rapidly over the subsequent days.(Macy IG. Am J Dis Child 1949;
78: 589-603.)
 Colostrum (in the first five days ): 22±12 mEq/ L,
 transitional milk (from day 5 to 10):13±3 mEq/L,
 mature milk (after 15 d): (7±2) mEq/ L.
 Normal physiological drop in breast milk sodium
concentration not occurred in cases with poor mother-
infant interaction. (Morton JA. Pediatrics 1994; 93: 802-6.)
 Commonest cause: low volume intake of breast milk.
 Low intake
 Incomplete response to Na load @ kidney
 High water loss through the skin, kidney and from the lungs.

6. Breastfed Hypernatremia
 Occurs in infants 1-3 weeks old
 First born children
 Cesarean
 Poor mother-infant interaction
 Limited human milk production
 Sodium content in human milk remains high

7. Clinical Manifestations
 Intracellular water shifts to extracellular space
 Child can then maintain intravascular volume
 Maintain BP and urine output longer
 No depressed fontanel
 Clinical signs underestimate true
degree of dehydration
 Wt. loss is more reliable
 Child appears more sicker than for
expected degree of dehydration
 Shock is a late sign

8. Clinical features (summary)
Central Nervous
System
Mild
Restlessness
Lethargy
Altered mental status
Irritability
Moderate
Disorientation
Confusion
Severe
Stupor
Coma
Seizures
Death
General
Preserved intra-vascular volume
Skin feels “doughy”
High-pitched cry
Insomnia
Fever
Respiratory System
Respiration distress
Gastrointestinal System
Intense thirst
Nausea
Vomiting
Musculoskeletal System
Muscle twitching
Spasticity
Hyperreflexia

9. Hypernatremia and the Brain
 Water shifts from inside brain cells to extracellular space
 Brain cells decrease in size (shrinkage)
 Total brain volume decreases
 Intracerebral blood vessels can tear
 Shearing forces
 Bridging veins can rupture as brain pulled away from
meninges/skull
 Hemorrhage
 Seizures
 Encephalopathy
 Paralysis

10. Thrombotic Complications
 Stroke
 Dural sinus thrombosis
 Peripheral thrombosis
 Renal vein thrombosis

11. Cerebral Edema in Hypernatremic Dehydration
 Brain develops idiogenic osmoles
 On correction these take time to decrease
 Faster correction will cause excessive shift of water
into the cells and thus cerebral edema
 Cerebellar herniation

13. Management approach
 Stabilize the child: Seizure control, Oxygen,
ventilator support, cardiopulmonary monitoring
 Physiology: Sodium gain vs water loss vs both
 Rapidity: Acute vs chronic
 Rate of correction: 0.5 mEq/L/hr (Max 12 mEq/day)

14. Lab investigation
 Blood
 RFT
 Lytes
 ABG
 Glucose, ca
 Urine
 Lytes
 SG/Osmolality

15. Measure Urine & Plasma Osmolality
U.osm<P.osm
U. Concentarting defect
CDI/NDI
Osmotic diuresis
Renal disease
U.osm>P.osm
Intact U. concentration
Diarrhea
Breastfed dehydration
Burn
/
Fever
Salt poisening

16. Treatment
 First priority is restoration of intravascular volume
 Goal: decrease serum sodium by 12-15 mEq/L/24
hours (0.5-0.6 mEq/L/hr)
 Frequent monitoring of serum sodium to ensure rate
of correction is not too fast

17. Treatment of hypernatremic dehydration:
Emergent phase
 Emergent Rehydration:
 Restoration of intravascular volume
 20 ml/kg NS (not ringer)
 Acute hypernatremia with neurological manifestation:
 Anticonvulsant
 Correct serum Na upto ↓5 mEq as rapid as 2 mEq/hr
 Neurological manifestation during correction
 Anticonvulsant
 Correct serum Na upto ↑5 mEq as rapid as 2 mEq/hr

18. Treatment of hypernatremic dehydration
 Phase 2: Determine the time of correction
 145-157: 24 hrs
 158-170: 48 hrs
 171-183: 72 hrs
 184-196: 84 hrs
 Replace ongoing losses with N/2 saline with KCl

19. Treatment of hypernatremic dehydration:
correction phase
 Step1:Estimate volume deficit (VD)
 Body wt. is best marker
 = free water loss + isotonic fluid deficit
 Step 2: calculate Free water deficit
 FWD= TBW(p)[(P.ser.Na/140)-1] (No Na)
 Isotonic F. loss= VD - FWD (140mEq Na/Lit

20. Example:
10Days old, BWt.=3 kg, Wt.=2.5, Ser.Na=170mEq/L
 Total Volume D.= 3-2.5= 0.5 Lit
 FWD=(2.5*0.7)((170/140)-1)= 0.375 Lit
 Isotonic D.= 0.5-0.375= 0.125 Lit
 Time of correction = 2.5 days
 First IV bolus: 20 mml/kg= 60 ml NS
Na (mEq)
volume
(ml)
Definition
-
375
FWD
16
125
Isotonic D.
Erdemir A,J Matern Fetal Neonatal Med
2014
Non-safe drop; IV vs Oral: 93% &30.7%
25
750
Maintenance
-8
-60
IV bolus
20 ml/hr
5% dextrose + 1/2 NS
33
1190
TOTAL

21. Type of fluid
 Does not matter, rate of correction matters
 May run two drips:
 1st: N/2 DNS with KCl
 2nd: N/5 + D5-10%W with KCl
 Monitor Na: 2- 6 hourly and adjust the rate
 Less decrease: increase N/5
 More decrease: increase N/2
 Thumb rule:(Nelson textbook of oediatrics, 20th ed.)
 Typical fluid: half normal salin + 5% D/W +Kcl
 Typical rate: 1.25-1.5 times maintanence

22. What if….
 Correction occurs too rapidly?
 Brain Edema
 Administer 3% NS to quickly reverse edema
 Dose: 4-6 ml/kg
 1ml/kg of 3% NS will change Na concentration by 1 meq/L
 Patient has hypernatremia secondary to sodium
administration
 The change is usually rapid-no time for idiogenic
osmoles to accumulate
 Can correct rapidly
 Peritoneal dialysis
 Administration D5W (no sodium) and loop diuretics

23. Key points
 Hypernatremia is usually due to dehydration (eg, caused by
diarrhea, vomiting, high fever); sodium overload is rare.
 Signs include lethargy, restlessness, hyperreflexia, spasticity,
hyperthermia, and seizures.
 Intracranial hemorrhage, venous sinus thrombosis, and acute
renal tubular necrosis may occur.
 Diagnose by finding serum sodium concentration > 150 mEq/L
(> 150 mmol/L).
 If the cause is dehydration, restore circulating blood volume
with 0.9% saline and then give 5% dextrose/0.3% to 0.45%
saline solution IV in volumes equal to the calculated fluid
deficit.
 Rehydrate over 2 to 3 days to avoid a too-rapid fall in serum
sodium, which can have significant adverse consequences.