What's the next step for an 84-year-old patient with improving hyponatremia, but decreasing White Blood Cell (WBC) count, while being treated with Miralax (polyethylene glycol) for constipation?

From the Guidelines

The next step for an 84-year-old patient with improving hyponatremia but decreasing WBC count while on Miralax should be to discontinue Miralax and perform a complete blood count with differential to evaluate the leukopenia. The patient should be switched to an alternative constipation treatment such as docusate sodium 100mg twice daily or senna 8.6mg daily. A comprehensive infectious workup should be initiated, including blood cultures, urinalysis, and chest X-ray to identify potential sources of infection, particularly given the patient's advanced age and vulnerability to sepsis. The decreasing WBC count could indicate bone marrow suppression, an adverse medication effect, or an evolving infection. While hyponatremia improvement is reassuring, the declining WBC count requires immediate attention as it could signal immunosuppression or infection. Miralax itself rarely causes leukopenia, but medication review is warranted to identify other potential causes. The patient should be monitored closely with repeat electrolyte panels to ensure continued improvement of hyponatremia while addressing the new concern of decreasing WBC count, as recommended by recent guidelines 1. Key considerations in managing the patient's hyponatremia include avoiding excessive correction of serum sodium concentration, which can cause central pontine myelinolysis or seizures, as noted in 1 and 1. However, the most recent and highest quality study 1 provides the best guidance for the next steps in management. Some key points to consider in the management of hyponatremia include:

• Discontinuation of diuretics if serum sodium is below 120 mmol/L, as recommended in 1 and 1
• Fluid restriction to 1-1.5 L/day in cases of severe hyponatremia, as recommended in 1 and 1
• Administration of hypertonic sodium chloride in severely symptomatic patients, as recommended in 1 and 1
• Monitoring for adverse events and adjusting treatment accordingly, as recommended in 1. Given the patient's improving hyponatremia, the focus should shift to addressing the decreasing WBC count, with the goal of preventing infection and immunosuppression. The patient's advanced age and vulnerability to sepsis necessitate a comprehensive and cautious approach to management, prioritizing morbidity, mortality, and quality of life as outcomes.

From the FDA Drug Label

USE • relieves occasional constipation (irregularity) • generally produces a bowel movement in 1 to 3 days WARNINGS Allergy alert: Do not use if you are allergic to polyethylene glycol

The patient's hyponatremia is improving, with sodium levels increasing from 123 to 130. However, the WBC count has decreased from 3.8 to 2.8. The patient is being treated with Miralax (polyethylene glycol) for constipation.

• The FDA drug label for Miralax does not provide information on the effect of the medication on WBC count or hyponatremia.
• The label only discusses the use of the medication for constipation and warns against use in patients allergic to polyethylene glycol 2 2. The FDA drug label does not answer the question.

From the Research

Patient's Condition

• The patient is an 84-year-old with improving hyponatremia, as indicated by a serum sodium level increase from 123 to 130 mEq/L 3, 4.
• The patient's White Blood Cell (WBC) count has decreased from 3.8 to 2.8, which may indicate leukopenia 5.
• The patient is being treated with Miralax (polyethylene glycol) for constipation, specifically constipation with overflow.

Hyponatremia Management

• Hyponatremia is defined as a serum sodium level of less than 135 mEq/L, and it can be categorized as mild, moderate, or severe based on the sodium concentration 4.
• The patient's sodium level is currently 130 mEq/L, which is considered mild to moderate hyponatremia.
• Treatment of hyponatremia should focus on addressing the underlying cause, and the approach may vary depending on the patient's fluid volume status (hypovolemic, euvolemic, or hypervolemic) 3, 4, 6.

Leukopenia Considerations

• Leukopenia can be caused by various factors, including medications, infections, or bone marrow disorders 5.
• A decrease in WBC count can increase the risk of infections, and patients with severe leukopenia may require immediate treatment with broad-spectrum antibiotics 5.
• It is essential to investigate the cause of the patient's leukopenia and monitor their condition closely.

Next Steps

• Continue to monitor the patient's sodium levels and adjust treatment as needed to avoid overly rapid correction, which can cause osmotic demyelination syndrome 3, 4, 7.
• Investigate the cause of the patient's leukopenia and consider further testing, such as a manual counted peripheral blood smear, to guide diagnosis and treatment 5.
• Review the patient's medication list, including Miralax, to determine if any medications may be contributing to the leukopenia or hyponatremia.