Hyponatremia in community-acquired pneumonia: a reasoned approach

Abstract

Hyponatremia is a common electrolyte disturbance in patients with community-acquired pneumonia. This narrative review critically examines the potential causes of hyponatremia in community-acquired pneumonia. Several mechanisms may contribute, including analytical artefacts related to sodium measurement techniques, pre-existing medical conditions, drug therapies, gastrointestinal fluid losses, inappropriate fluid intake, pneumonia severity, microbiological etiology, sex-related biological differences, and hypoalbuminemia. Although SIAD has traditionally been regarded as the predominant mechanism of pneumonia- associated hyponatremia, the available evidence suggests that its role may be less central than previously assumed. Rather, hyponatremia in this setting is likely to result from the interplay of multiple factors. Consequently, the diagnostic evaluation should begin with a systematic assessment of different causes, including comorbidities, medications, fluid and electrolyte losses, and clinical features reflecting the severity of the underlying infection.