How to manage severe hyponatremia in a 69-year-old patient?

Management of Severe Hyponatremia in a 69-Year-Old Patient with Sodium 108 and Chloride 76

For severe hyponatremia with sodium of 108 mmol/L, immediate treatment with 3% hypertonic saline is required to increase serum sodium by 4-6 mEq/L in the first 1-2 hours, followed by careful monitoring to avoid exceeding a correction rate of 8 mmol/L per 24 hours. 1

Initial Assessment and Classification

1. Determine volume status (hypovolemic, euvolemic, or hypervolemic) by:

   • Assessing clinical signs (edema, ascites, orthostatic hypotension)
   • Measuring urine osmolality and urine sodium concentration
   • Evaluating serum osmolality

2. Laboratory assessment:

   Volume Status	Urine Osmolality	Urine Sodium	Suggested Diagnosis
   Hypovolemic	Variable	<20 mEq/L	Volume depletion
   Euvolemic	>500 mOsm/kg	>20-40 mEq/L	SIADH
   Hypervolemic	Elevated	<20 mEq/L	Heart failure, cirrhosis

Emergency Treatment Algorithm

For Severe Symptoms (seizures, altered mental status, coma):

1. Administer 3% hypertonic saline:

   • Initial bolus: 100-150 mL over 10-20 minutes
   • Goal: Increase serum sodium by 4-6 mEq/L in first 1-2 hours
   • Transfer to ICU for close monitoring
   • Calculate sodium deficit using formula: Desired increase in Na (mEq) × (0.5 × ideal body weight) 1

2. Monitoring during correction:

   • Check serum sodium every 2-4 hours initially
   • Limit correction to maximum 8 mmol/L in first 24 hours 2, 1
   • For high-risk patients (alcoholism, malnutrition, liver disease), limit to 4-6 mmol/L per day 1

For Moderate Symptoms (nausea, vomiting, headache):

1. Consider 3% hypertonic saline at slower rate if symptoms are concerning
2. Monitor serum sodium every 4-6 hours

Specific Treatment Based on Volume Status

Hypovolemic Hyponatremia:

1. Administer isotonic saline (0.9% NaCl) for volume expansion
2. Identify and treat underlying cause (e.g., diuretic use, GI losses)
3. Temporarily discontinue diuretics if applicable 1

Euvolemic Hyponatremia (SIADH):

1. Fluid restriction (<1 L/day) for ongoing management
2. Consider salt tablets or oral urea if available
3. For persistent cases, consider tolvaptan (vaptan) for short-term use (1 week to 1 month) 2, 3
   • Start with 15 mg once daily
   • Can be titrated to 30 mg, then 60 mg daily as needed
   • Monitor for rapid correction and thirst

Hypervolemic Hyponatremia (Heart Failure, Cirrhosis):

1. Treat underlying condition
2. Sodium restriction (5-6.5 g/day for cirrhosis, 2 g/day for heart failure) 1
3. Judicious use of diuretics after initial correction
4. Consider albumin infusion for patients with cirrhosis 2
5. Short-term use of vaptans may be considered in specific cases 2, 3

Avoiding Complications

1. Prevent osmotic demyelination syndrome:

   • Avoid correction exceeding 8 mmol/L per 24 hours
   • If correction occurs too rapidly, consider administering hypotonic fluids or desmopressin to re-lower sodium 1, 4
   • Higher risk in alcoholism, malnutrition, liver disease, and chronic hyponatremia 5

2. Monitor for:

   • Serum sodium levels (every 4-6 hours initially, then daily)
   • Volume status
   • Serum potassium
   • Kidney function
   • Urine output 1

Special Considerations for This Patient

With sodium of 108 mmol/L, this patient has severe hyponatremia requiring urgent intervention. The low chloride (76 mmol/L) suggests possible metabolic alkalosis, which may provide clues to the underlying cause (e.g., diuretic use, vomiting).

The treatment approach should be guided by:

• Presence/absence of severe symptoms
• Duration of hyponatremia (acute vs. chronic)
• Volume status
• Underlying cause

The correction rate should be carefully controlled, with more conservative correction (4-6 mmol/L per day) if chronic hyponatremia is suspected, particularly given the patient's age of 69 years, which increases risk of complications from overly rapid correction 6, 7.