From the Guidelines
Sepsis and bacteremia can indeed cause hypernatremia, which is a significant concern due to its association with increased mortality. During severe infections like sepsis, multiple mechanisms can lead to elevated sodium levels, including insensible water losses through fever, tachypnea, and diaphoresis without adequate fluid replacement, as well as antidiuretic hormone dysfunction and acute kidney injury, which impairs the kidney's ability to conserve water 1.
Key Mechanisms and Considerations
- Insensible water losses: Patients with sepsis often experience fever, tachypnea, and diaphoresis, leading to water loss without adequate replacement.
- Antidiuretic hormone dysfunction: Sepsis can trigger dysfunction in antidiuretic hormone, impairing the kidney's ability to conserve water.
- Acute kidney injury: Septic patients frequently develop acute kidney injury, disrupting sodium and water balance.
- Iatrogenic causes: Septic patients may receive sodium-rich fluids or medications, contributing to hypernatremia.
Management and Treatment
Prompt management with careful fluid resuscitation is crucial, typically using hypotonic fluids like 0.45% saline or 5% dextrose in water. The correction rate should not exceed 10 mEq/L in 24 hours to prevent neurological complications. Regular monitoring of serum sodium levels, fluid status, and addressing the underlying infection with appropriate antibiotics are essential components of treatment. While the provided evidence primarily discusses fluid management and continuous renal replacement therapy (CRRT) in sepsis, the principles of careful fluid management and monitoring apply to preventing and managing hypernatremia in these patients 1.
From the Research
Sepsis and Bacteremia as Causes of Hypernatremia
- Sepsis can contribute to the development of hypernatremia, as evidenced by a study published in 2014, which found that severe sepsis patients receiving 0.9% saline fluid resuscitation were at risk of developing hypernatremia 2.
- The study found that for every 50-ml/kg increase in 0.9% saline intake for the first 48 hours, the odds of hypernatremia were 1.61 times larger, and the mean of ΔNap increased by 1.86 mmol/L 2.
- Another study published in 2016 found that acute physiology and chronic health evaluation II score was an independent risk factor for hypernatremia in patients with sepsis, and that patients developing hypernatremia during hospitalization showed significantly higher morbidity and mortality 3.
- Bacteremia, which is often associated with sepsis, can also contribute to the development of hypernatremia, although there is limited direct evidence on this topic.
- A study published in 2019 found a positive correlation between hypernatremia on admission and the presence of sepsis, suggesting that hypernatremia may serve as a potential surrogate marker for sepsis 4.
Mechanisms and Risk Factors
- Hypernatremia is defined as a serum sodium level above 145 mmol/L, and can result from a variety of mechanisms, including excessive sodium intake, insufficient free water intake, and dysfunction of the body's osmoregulatory mechanisms 5, 6.
- Sepsis and bacteremia can disrupt the body's osmoregulatory mechanisms, leading to the development of hypernatremia.
- Other risk factors for hypernatremia in patients with sepsis include acute physiology and chronic health evaluation II score, as well as the volume of 0.9% saline received during the first 48 hours of admission 2, 3.
Clinical Implications
- Hypernatremia is associated with increased morbidity and mortality in patients with sepsis, and prompt recognition and treatment are essential to improve outcomes 2, 3, 4.
- Clinicians should be aware of the potential for hypernatremia in patients with sepsis, and should investigate for sources of infection in patients with hypernatremia, especially in the elderly and patients with dementia 4.