How to correct hypernatremia (elevated sodium level) of 152 mmol/L?

Correcting Hypernatremia of 152 mmol/L

For a sodium level of 152 mmol/L, calculate the free water deficit and replace it with hypotonic fluids (0.45% NaCl or D5W) at a correction rate not exceeding 10 mmol/L per 24 hours, while addressing the underlying cause. 1, 2

Immediate Assessment

Determine chronicity and volume status:

• Acute hypernatremia (<24-48 hours): Can be corrected more rapidly without risk of cerebral edema 1, 3
• Chronic hypernatremia (>48 hours): Requires slow correction at no more than 0.4 mmol/L/hour (maximum 8-10 mmol/L per 24 hours) to prevent cerebral edema 1, 3
• Assess volume status: Look for signs of dehydration (dry mucous membranes, decreased skin turgor, hypotension, tachycardia) vs. hypervolemia (edema, jugular venous distention) 2, 4

Check urine osmolality and volume:

• High urine osmolality (>600-800 mOsm/kg) with low urine volume suggests extrarenal water losses or impaired thirst mechanism 4
• Low urine osmolality (<300 mOsm/kg) with high urine volume suggests diabetes insipidus 1, 4

Calculate Water Deficit

Use the formula: Water deficit (L) = 0.6 × body weight (kg) × [(current Na ÷ 140) - 1] 2, 4

For a 70 kg patient with Na 152: Water deficit = 0.6 × 70 × [(152 ÷ 140) - 1] = 3.6 liters 2

Correction Strategy

Choose hypotonic fluid based on severity:

• 0.45% NaCl (half-normal saline): Preferred for most cases of hypernatremia, provides 77 mEq/L sodium 5, 2
• D5W (5% dextrose in water): For severe hypernatremia or when more aggressive free water replacement needed 5, 2
• Avoid isotonic saline (0.9% NaCl): Will worsen hypernatremia in patients with impaired free water excretion 5

Correction rate limits:

• Chronic hypernatremia: Maximum 8-10 mmol/L per 24 hours (0.4 mmol/L/hour) 1, 3
• Acute hypernatremia (<24 hours): Can correct more rapidly, but still monitor closely 1
• For Na 152 mmol/L: Target reduction to 142-144 mmol/L over first 24 hours (8-10 mmol/L decrease) 1, 3

Specific Treatment Based on Etiology

Hypovolemic hypernatremia (most common):

• Replace water deficit with 0.45% NaCl over 24-48 hours 2, 4
• Add ongoing losses and insensible losses (typically 500-1000 mL/day) 4
• Monitor urine output and adjust fluid rate accordingly 4

Diabetes insipidus (if suspected):

• Central DI: Desmopressin (DDAVP) 1-2 mcg IV/SC or 10-20 mcg intranasal 1, 3
• Nephrogenic DI: Address underlying cause (stop lithium, correct hypokalemia), provide hypotonic fluids 1

Hypervolemic hypernatremia (rare):

• Consider hemodialysis for rapid correction if acute and severe 3
• Use loop diuretics with hypotonic fluid replacement 1

Monitoring Protocol

Check sodium levels:

• Every 2-4 hours during initial correction phase 2, 4
• Adjust fluid rate if correction too rapid or too slow 4

Watch for complications:

• Cerebral edema: From overly rapid correction of chronic hypernatremia (confusion, seizures, altered mental status) 1, 3
• Ongoing losses: Reassess volume status and urine output frequently 4

Critical Pitfalls to Avoid

• Never correct chronic hypernatremia faster than 10 mmol/L per 24 hours - risks cerebral edema from rapid osmotic shifts 1, 3
• Never use isotonic saline in patients with impaired free water excretion - will worsen hypernatremia 5
• Never ignore ongoing losses - must replace both deficit AND ongoing losses (insensible, urine, GI) 4
• Never start renal replacement therapy without adjusting dialysate sodium - can cause precipitous sodium drop 3