Discharge Criteria for Patients Admitted with Hyponatremia
The primary criterion for discharge in patients admitted with hyponatremia is resolution of the acute episode, particularly absence of congestion, and establishment of a stable oral diuretic regimen for at least 48 hours. 1
Assessment of Clinical Stability
Vital Signs and Symptoms
- Absence of significant dyspnea or hemodynamic instability
- Resting heart rate <100 bpm
- No hypotension when standing up
- Adequate urine output
- Oxygen saturation >95% in room air 1
Laboratory Parameters
- Serum sodium correction to safe levels (generally >130 mEq/L)
- Stable electrolytes for at least 24-48 hours
- Resolution of any associated metabolic abnormalities
- Daily monitoring of blood urea nitrogen, creatinine, potassium, and sodium during hospitalization 1
Sodium Correction Targets
Rate of Correction
- For chronic hyponatremia: Avoid correction exceeding 8 mEq/L in 24 hours for high-risk patients (including those with advanced liver disease) 1
- For standard risk patients: Limit correction to 10-12 mEq/L in 24 hours 1
- For severe hyponatremia (<120 mEq/L): More gradual correction is required to prevent osmotic demyelination syndrome 1
Monitoring Requirements
- Daily weight measurements
- Fluid intake and output monitoring
- Jugular venous pressure assessment
- Evaluation of peripheral edema 1
Cause-Specific Considerations
Heart Failure-Related Hyponatremia
- Ensure congestion is absent
- Establish a stable oral diuretic regimen for at least 48 hours
- Optimize disease-modifying therapy including beta-blockers 1
- Consider ultrafiltration for patients with refractory congestion not responding to medical therapy 1
Liver Disease-Related Hyponatremia
- For mild hyponatremia (>130 mEq/L): No specific treatment required before discharge
- For moderate hyponatremia (120-125 mEq/L): Trial of fluid restriction to 1,000 mL/day
- For severe hyponatremia (<120 mEq/L): More severe fluid restriction plus albumin infusion 1
SIADH-Related Hyponatremia
- Ensure stable sodium levels with appropriate fluid restriction
- Consider if vasopressin receptor antagonists (vaptans) are needed for long-term management in appropriate patients 2, 3
- Ensure patient understands fluid restriction requirements
Pre-Discharge Planning
Medication Management
- Reconcile all medications
- Adjust diuretic dosing based on the patient's "dry weight" 1
- Provide clear instructions on medication type, purpose, dose, and frequency
- Ensure patient has access to prescribed medications
Education
- Instruct on daily weight monitoring
- Educate on dietary sodium restriction (typically ≤2g daily) 1
- Provide fluid restriction guidelines if applicable
- Explain symptoms that should prompt medical attention
Follow-up Planning
- Schedule early follow-up appointment (ideally within 7 days)
- Arrange for laboratory monitoring of electrolytes after discharge
- Consider enrollment in a heart failure program for patients with heart failure-related hyponatremia 1
Common Pitfalls to Avoid
Premature discharge: Patients sent home before euvolemia is achieved are at high risk of recurrence of fluid retention and early readmission 1
Overly rapid correction: Correction exceeding 8-10 mEq/L in 24 hours increases risk of osmotic demyelination syndrome, especially in high-risk patients 1
Inadequate follow-up planning: Poor transitions of care increase risk for decompensation in days/weeks post-discharge 4
Failure to address underlying cause: Recurrence is likely if the primary etiology of hyponatremia is not addressed
Inadequate patient education: Patients must understand fluid/sodium restrictions and medication regimens to prevent recurrence
By following these principles, clinicians can ensure safe discharge of patients admitted with hyponatremia while minimizing the risk of readmission and complications.