Abstract
Hyponatremia can occur with central nervous system (CNS) infections, but the frequency and severity may depend on the organism and nature of CNS involvement. In this cross-sectional study at a large Australian hospital network from 2015 to 2018, we aimed to determine the prevalence and severity of hyponatremia associated with CNS infection clinical syndromes, and the association with specific organisms. We examined the results of cerebrospinal fluid analysis from lumbar punctures performed in 184 adult patients with a serum sodium below 135 mmol/L who had abnormal cerebrospinal fluid analysis and a clinical syndrome consistent with an acute CNS infection (meningitis or encephalitis). Hyponatremia affected 39% of patients and was more severe and frequent in patients with encephalitis compared to meningitis (odds ratio = 3.03, 95% CI: 1.43–6.39, after adjusting for age). Hyponatremia was present on admission in 85% of cases. Herpes simplex virus infection was associated with the highest odds of hyponatremia (odds ratio = 3.25, 95% CI: 1.13–7.87) while enterovirus infection was associated with the lowest (odds ratio = 0.36, 95% CI: 0.14–0.92), compared to cases without an isolated organism. We concluded that the risk of hyponatremia may vary by the organism isolated but the clinical syndrome was a useful surrogate for predicting the probability of developing hyponatremia.
Highlights
Acute central nervous system (CNS) infections are neurological emergencies which require prompt and effective treatment to avoid morbidity and mortality
Hyponatremia is the most common electrolyte abnormality in hospitalized patients, especially those with critical neurological injuries and is associated with increased mortality and hospital length of stay [26,27,28]. In this cross-sectional study at a large hospital network, we examined cerebrospinal fluid results in patients with CNS infection and confirmed that hyponatremia is a common manifestation of CNS infection, affecting 39% of cases
We demonstrated an association between hyponatremia and CNS infection with herpes simplex virus (HSV) and enteroviruses, and an association between hyponatremia and the clinical syndrome of meningitis or encephalitis at presentation
Summary
Acute central nervous system (CNS) infections are neurological emergencies which require prompt and effective treatment to avoid morbidity and mortality. CNS infections may take the form of meningitis, encephalitis or brain abscesses. The cases with overlapping clinical features of meningeal irritation and brain parenchymal involvement are sometimes referred to as meningoencephalitis. The majority of CNS infections are community-acquired but some patients may develop healthcare-associated meningitis in the setting of trauma or intracranial cerebrospinal fluid shunts and external drains. The organisms commonly isolated in adult cases of community-acquired bacterial meningitis include Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and in older adults, Listeria monocytogenes. Many organisms, including bacterial, viral, fungal and protozoans, are capable of infecting brain tissue leading to encephalitis, the most common are viral, in particular, herpes simplex virus (HSV). Cryptococcus species are the most common fungal organism implicated in CNS infections, particular in immunocompromised patients [4]. It has been recognized that encephalitis occurs just as frequently as purulent meningitis [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
