From the Guidelines
To treat this patient's hyponatremia, I recommend discontinuing the diuretic (Lasix) and expanding plasma volume with normal saline, as the patient's sodium level is 130 mmol/L and she is likely experiencing diuretic-induced hyponatremia. The patient has moderate chronic kidney disease (CKD stage 3b with GFR 43) and is taking furosemide 20mg daily, which can impair urinary dilution capacity and lead to relative water excess. First, evaluate for symptoms of hyponatremia such as confusion, headache, or nausea. If symptoms are severe or sodium is rapidly declining, hospitalization may be necessary. For this outpatient management, consider fluid restriction to 1-1.5 liters per day if the patient is clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/day) 1. However, the most recent and highest quality study suggests that hypovolaemic hyponatraemia during diuretic therapy should be managed by discontinuation of diuretics and expansion of plasma volume with normal saline 1. Monitor electrolytes twice weekly initially, then weekly until sodium normalizes. Avoid rapid correction (no more than 8 mEq/L in 24 hours) to prevent osmotic demyelination syndrome, as suggested by other studies 1. The patient's reduced kidney function further compromises sodium handling, making her more susceptible to electrolyte abnormalities. It is essential to prioritize the patient's volume status and sodium level to determine the best course of treatment. In this case, discontinuing the diuretic and expanding plasma volume with normal saline is the most appropriate treatment, as it addresses the underlying cause of the hyponatremia and minimizes the risk of complications.
From the FDA Drug Label
Patients receiving Furosemide tablets should be advised that they may experience symptoms from excessive fluid and/or electrolyte losses Serum electrolytes (particularly potassium), CO2, creatinine and BUN should be determined frequently during the first few months of Furosemide tablets therapy and periodically thereafter. Abnormalities should be corrected or the drug temporarily withdrawn.
The patient's low sodium level may be due to excessive fluid and/or electrolyte losses caused by Furosemide. To treat her low sodium, correction of abnormalities is necessary. This may involve adjusting the Furosemide dosage or temporarily withdrawing the drug, as well as monitoring and managing electrolyte levels, including sodium. However, the exact treatment approach is not explicitly stated in the label. 2
From the Research
Patient's Condition
The patient has a sodium level of 130 mEq/L, which is considered mild hyponatremia 3. The patient is also taking lasix 20mg daily, which is a loop diuretic.
Causes of Hyponatremia
Hyponatremia can be caused by various factors, including certain medications, excessive alcohol consumption, very low-salt diets, and excessive free water intake during exercise 3. Loop diuretics like lasix can also contribute to hyponatremia, especially in patients with high water intake or those who depend on the excretion of maximally dilute urine to maintain fluid balance 4, 5.
Treatment of Hyponatremia
The treatment of hyponatremia depends on the underlying cause and the patient's volume status 3. Since the patient is taking lasix, which is a loop diuretic, it is likely that the patient has hypervolemic hyponatremia. The treatment for hypervolemic hyponatremia primarily involves managing the underlying cause and restricting free water intake 3.
Management of Hypervolemic Hyponatremia
In this case, the patient's lasix dose may need to be adjusted or discontinued to manage the hyponatremia 4, 5. Additionally, the patient's free water intake should be restricted to help correct the sodium level 3. It is also important to identify and manage any underlying conditions that may be contributing to the hyponatremia.
Key Considerations
- The patient's sodium level should be monitored closely to avoid overly rapid correction, which can cause osmotic demyelination syndrome 3, 6.
- The patient's potassium level should also be monitored, as hypokalemia can increase the susceptibility to osmotic demyelination syndrome 4.
- The use of loop diuretics like lasix may need to be re-evaluated, as they can contribute to hyponatremia, especially in patients with high water intake or those who depend on the excretion of maximally dilute urine to maintain fluid balance 4, 5.