Rapid Sodium Rise from 141 to 155 mmol/L in One Day
A sudden jump in sodium from 141 to 155 mmol/L within 24 hours represents acute hypervolemic hypernatremia, most commonly caused by intraoperative or perioperative administration of large volumes of sodium-containing products (packed red blood cells, fresh frozen plasma, or hypertonic saline solutions), particularly in the context of liver transplantation or major surgery. 1
Primary Causes of Acute Hypernatremia
Iatrogenic Sodium Overload (Most Common)
- Intraoperative fluid administration is the leading cause, particularly during liver transplantation where massive transfusion of blood products and saline solutions can rapidly elevate serum sodium 1
- Hypertonic saline (3% NaCl) administration for cerebral edema or severe hyponatremia correction can overshoot the target, especially if monitoring is inadequate 1, 2
- Sodium bicarbonate infusions during resuscitation or metabolic acidosis correction 2
Excessive Sodium Intake
- Ingestion of supersaturated salt solutions (even 70-90 g of table salt can cause severe hypernatremia with sodium levels >200 mmol/L) 3
- Hypertonic saline used as an emetic (dangerous and potentially fatal) 3
Renal Water Loss Without Adequate Replacement
- Diabetes insipidus (central or nephrogenic) with inadequate free water access 2, 4
- Osmotic diuresis from hyperglycemia, mannitol, or contrast agents 5
Extrarenal Water Loss
- Severe diarrhea, vomiting, or burns with replacement using isotonic rather than hypotonic fluids 2, 5
- Insensible losses in febrile or mechanically ventilated patients 5
Critical Diagnostic Approach
Immediately assess:
- Volume status: Look for signs of hypervolemia (edema, elevated JVP, pulmonary congestion) versus hypovolemia (hypotension, tachycardia, dry mucous membranes) 2, 4
- Recent fluid administration: Review all IV fluids, blood products, and medications given in the past 24 hours 1
- Urine osmolality: >600-800 mOsm/kg suggests extrarenal water loss; <300 mOsm/kg suggests diabetes insipidus 2, 4
- Urine sodium: High urine sodium with dilute urine indicates renal water wasting 2
Immediate Management Priorities
For Acute Hypernatremia (<48 hours)
Rapid correction is safer and improves prognosis by preventing cellular dehydration effects 2
- Calculate free water deficit: Free water deficit (L) = 0.6 × body weight (kg) × [(current Na/140) - 1] 4
- Administer hypotonic fluids: Use 5% dextrose (D5W) or 0.45% NaCl 4, 6
- Target correction rate: 1 mmol/L per hour is acceptable for acute hypernatremia 2
- Avoid isotonic saline: This will worsen hypernatremia by delivering excessive osmotic load 5
For Chronic Hypernatremia (>48 hours)
Slow correction is mandatory to prevent cerebral edema 2, 6
- Maximum correction rate: 0.4 mmol/L per hour or 8-10 mmol/L per 24 hours 2, 6
- Monitor sodium every 2-4 hours during active correction 6
Special Considerations for Liver Disease/Transplant Patients
- Multidisciplinary coordination is essential to prevent osmotic demyelination syndrome (ODS), which occurs in 0.5-1.5% of liver transplant recipients 1
- Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy are at highest risk for ODS 1
- If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1
Common Pitfalls to Avoid
- Failing to identify iatrogenic causes: Always review the medication administration record and operative notes for sodium-containing products 1
- Using isotonic fluids in hypernatremia: This delivers 154 mEq/L sodium and requires 3 liters of urine to excrete the osmotic load from just 1 liter of fluid 5
- Correcting chronic hypernatremia too rapidly: This causes cerebral edema and can be fatal 2, 6
- Missing diabetes insipidus: Check urine osmolality; if <300 mOsm/kg despite hypernatremia, consider desmopressin trial 2, 4