Treatment of Hyponatremic Encephalopathy
Treatment of Hyponatremic Encephalopathy
Background 3% sodium chloride solution is the accepted treatment for hyponatremic encephalopathy, but evidence-based guidelines for its use are lacking.
Study Design A case series.
Setting & Participants Adult patients presenting to the emergency department of a university hospital with hyponatremic encephalopathy, defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause, and treated with a continuous infusion of 500 mL of 3% sodium chloride solution over 6 hours through a peripheral vein.
Predictors Hyponatremic encephalopathy defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause.
Outcomes Change in serum sodium level within 48 hours, improvement in neurologic symptoms, and clinical evidence of cerebral demyelination, permanent neurologic injury, or death within 6 months' posttreatment follow-up.
Results There were 71 episodes of hyponatremic encephalopathy in 64 individuals. Comorbid conditions were present in 86% of individuals. Baseline mean serum sodium level was 114.1 ± 0.8 (SEM) mEq/L and increased to 117.9 ± 1.3, 121.2 ± 1.2, 123.9 ± 1.0, and 128.3 ± 0.8 mEq/L at 3, 12, 24, and 48 hours following the initiation of 3% sodium chloride solution treatment, respectively. There was a marked improvement in central nervous system symptoms within hours of therapy in 69 of 71 (97%) episodes. There were 12 deaths, all of which occurred following the resolution of hyponatremic encephalopathy and were related to comorbid conditions, with 75% of deaths related to sepsis. No patient developed neurologic symptoms consistent with cerebral demyelination at any point during the 6-month follow-up period.
Limitations Lack of a comparison group and follow-up neuroimaging studies. Number of cases is too small to provide definitive assessment of the safety of this protocol.
Conclusions 3% sodium chloride solution was effective in reversing the symptoms of hyponatremic encephalopathy in the emergency department without producing neurologic injury related to cerebral demyelination on long-term follow-up in this case series.
Hyponatremia is the most common electrolyte abnormality in the inpatient and outpatient setting. Hyponatremic encephalopathy is the most serious complication of hyponatremia. Significant risk factors for developing hyponatremic encephalopathy include female sex, hypoxia, and underlying central nervous system disease. The symptoms of hyponatremic encephalopathy are largely related to cerebral edema. Hyponatremic encephalopathy constitutes a medical emergency because it might lead to death or permanent neurologic deterioration due to transtentorial herniation or respiratory arrest if untreated.
According to the recent European Clinical Practice Guidelines, hypertonic saline solution is recommended for the treatment of hyponatremic encephalopathy regardless of whether it is acute or chronic. They acknowledge that "the body of evidence to base recommendations on this topic was limited.") The guidelines' recommendation for hypertonic saline solution were based on 9 case series that varied widely in regard to the setting, symptoms, severity, duration, and therapy used to treat hyponatremic encephalopathy. According to the guidelines, most case reports used a total of 500 mL of 3% sodium chloride solution. The guidelines recommend using repeated 150-mL boluses of hypertonic saline solution, but they acknowledge that "there is no evidence in published research to support this assertion.") In this article, we evaluated the efficacy and safety of a uniform treatment protocol of 500 mL of 3% sodium chloride solution infused over 6 hours for the management of hyponatremic encephalopathy in the emergency department.
Abstract and Introduction
Abstract
Background 3% sodium chloride solution is the accepted treatment for hyponatremic encephalopathy, but evidence-based guidelines for its use are lacking.
Study Design A case series.
Setting & Participants Adult patients presenting to the emergency department of a university hospital with hyponatremic encephalopathy, defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause, and treated with a continuous infusion of 500 mL of 3% sodium chloride solution over 6 hours through a peripheral vein.
Predictors Hyponatremic encephalopathy defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause.
Outcomes Change in serum sodium level within 48 hours, improvement in neurologic symptoms, and clinical evidence of cerebral demyelination, permanent neurologic injury, or death within 6 months' posttreatment follow-up.
Results There were 71 episodes of hyponatremic encephalopathy in 64 individuals. Comorbid conditions were present in 86% of individuals. Baseline mean serum sodium level was 114.1 ± 0.8 (SEM) mEq/L and increased to 117.9 ± 1.3, 121.2 ± 1.2, 123.9 ± 1.0, and 128.3 ± 0.8 mEq/L at 3, 12, 24, and 48 hours following the initiation of 3% sodium chloride solution treatment, respectively. There was a marked improvement in central nervous system symptoms within hours of therapy in 69 of 71 (97%) episodes. There were 12 deaths, all of which occurred following the resolution of hyponatremic encephalopathy and were related to comorbid conditions, with 75% of deaths related to sepsis. No patient developed neurologic symptoms consistent with cerebral demyelination at any point during the 6-month follow-up period.
Limitations Lack of a comparison group and follow-up neuroimaging studies. Number of cases is too small to provide definitive assessment of the safety of this protocol.
Conclusions 3% sodium chloride solution was effective in reversing the symptoms of hyponatremic encephalopathy in the emergency department without producing neurologic injury related to cerebral demyelination on long-term follow-up in this case series.
Introduction
Hyponatremia is the most common electrolyte abnormality in the inpatient and outpatient setting. Hyponatremic encephalopathy is the most serious complication of hyponatremia. Significant risk factors for developing hyponatremic encephalopathy include female sex, hypoxia, and underlying central nervous system disease. The symptoms of hyponatremic encephalopathy are largely related to cerebral edema. Hyponatremic encephalopathy constitutes a medical emergency because it might lead to death or permanent neurologic deterioration due to transtentorial herniation or respiratory arrest if untreated.
According to the recent European Clinical Practice Guidelines, hypertonic saline solution is recommended for the treatment of hyponatremic encephalopathy regardless of whether it is acute or chronic. They acknowledge that "the body of evidence to base recommendations on this topic was limited.") The guidelines' recommendation for hypertonic saline solution were based on 9 case series that varied widely in regard to the setting, symptoms, severity, duration, and therapy used to treat hyponatremic encephalopathy. According to the guidelines, most case reports used a total of 500 mL of 3% sodium chloride solution. The guidelines recommend using repeated 150-mL boluses of hypertonic saline solution, but they acknowledge that "there is no evidence in published research to support this assertion.") In this article, we evaluated the efficacy and safety of a uniform treatment protocol of 500 mL of 3% sodium chloride solution infused over 6 hours for the management of hyponatremic encephalopathy in the emergency department.
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