A Cross-Sectional Study of Hyponatremia Associated with Acute Central Nervous System Infections

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.

Hyponatremia in Infectious Diseases—A Literature Review

“…Other viral infections associated with hyponatremia include human herpesvirus-6 (HHV-6), SFTS virus (SFTSV), hantavirus, herpes simplex virus (HSV), and Ebola virus infections [ 34 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

“…Hyponatremia, both hypovolemic and euvolemic is associated with all viral CNS infections due to vomiting, SIADH, or fever. That is why CNS infections are related with high incidence of hyponatremia that reaches 30–66% [ 36 ]. In general, hyponatremia is associated with CNS infections in about 30–66% of cases [ 36 ].…”

“…That is why CNS infections are related with high incidence of hyponatremia that reaches 30–66% [ 36 ]. In general, hyponatremia is associated with CNS infections in about 30–66% of cases [ 36 ]. It has been observed that low serum sodium levels appear more frequently in CNS HSV infections.…”

“…It has been observed that low serum sodium levels appear more frequently in CNS HSV infections. Thus, it has been suggested that serum sodium could be used to differentiate the HSV vs. non-HSV encephalitis etiology [ 36 , 37 ].…”

Higher plasma NT-proBNP levels correlate with syndrome of inappropriate antidiuretic hormone and poor prognosis in neurological patients

“…Other groups reported relatively lower prevalence of hyponatremia which was around 4.5% depending on the underlying conditions (6,7). Nevertheless, it has been widely recognized that up to 10-50% of neurological patients have concurrent hyponatremia (8)(9)(10). Fluctuation in the plasma osmolarity is detected by specialized neurons, namely osmoreceptors, located in the anteromedial hypothalamus.…”