Hyponatremia Related to Neurocritical Care: Focus on Diagnosis and Therapy: A Systematic Review.

Introduction: Hyponatremia is the most frequently occurring electrolyte disorder in neurocritical care and traumatic brain injury, aneurysmal subarachnoid hemorrhage (SAH), neurosurgery, and ischemic stroke are the clinical conditions more often associated with this condition. SIADH and CSWS are the main causes of hyponatremia in neurologically ill patients. Since hyponatremia is a negative prognostic factor for neurocritical patients, early diagnosis and consequent targeted therapy are of fundamental importance. The present review was carried out to provide a brief recap on the main causes and management of hyponatremia in the neurocritical patient.

Methods: A methodical search of the medical literature using the online database MEDLINE was carried out and studies comprising case reports, prospective and retrospective observational studies, or randomized controlled clinical trials in which there is a diagnosis of hyponatremia in neurocritical patients were included.

Results: 18 articles were analyzed, consisting of 8 case reports, 4 case series, 3 prospective trials, 1 retrospective study, and 1 multicenter trial. A total of 1371 patients from 18 studies were included. Patients' average age was 29.28 ± 20.9, respectively. TBI was the main cause of hyponatremia in the literature reviewed; 12 studies were about the relationship between TBI and hyponatremia, 2 studies about stroke, 2 studies about SAH and 1 about hyponatremia postneurosurgical procedure.

Discussion: Hyponatremia is the most common electrolyte disorder in hospitalized patients and the main scenarios of hyponatremic neurocritical patients are subarachnoid hemorrhage, ischemic stroke, traumatic brain injury and iatrogenic hyponatremia due to neurosurgical cases.

Conclusion: Hyponatremia is a frequent finding in neurocritical care and is also a recognized negative prognostic factor leading to increased mortality and ICU length hospitalization. Its diagnosis and therapy are essential for correct neurocritical management. The most common cause of serum sodium abnormality is SIADH, and an early diagnosis for target treatment is paramount to prevent delayed symptoms and complications.