Frequency of Hyponatraemia in Patients Admitted With Community Acquired Pneumonia in Medical Unit of Teaching Hospital

Abstract

Background: Hyponatraemia is frequently found in community-acquired pneumonia (CAP) and contributes to a higher rate of morbidity and mortality. There is a paucity of data on the mechanism and treatment of hyponatremia in CAP Objectives: the aim of the present study was to determine the frequency of hyponatremia in patients admitted with community-acquired pneumonia in tertiary care hospital. Methodology: This prospective observational study was carried out on 1246 CAP patients admitted to the Medical Unit of DHQ hospital, Dera Ismail Khan from July 2020 to January 2022. Patients who experienced the onset of pneumonia and hyponatremia (with sodium levels ≤ 130 mmol/L) within the initial 48 hours of admission were incorporated into the study. In a total of eligible patient’s admissions for community-acquired pneumonia (CAP), the prevalence and corresponding mortality rates for each subtype of hyponatremia were investigated. A subgroup of patients diagnosed with the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIAD) was actively observed over time to record and study the natural progression of SIAD in the context of community-acquired pneumonia (CAP). Results: The prevalence of hyponatremia (≤130 mmol/l) in CAP patients was 9.5% (n=118). Among 118 hyponatraemia patients, the incidence of euvolaemic hyponatremia, hypovolemic hyponatremia (HEN) and hypotonic hyponatremia (HON) was 50.8% (n=60), 8.5% (n=10) and 40.7% (n=48) respectively. Out of 60 euvolaemic hyponatremia cases, the incidence of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIAD) and steroid deficiency was 47.5% (n=56) and 3.4% (n=4) respectively. Hypovolemic hyponatremia consistently stemmed from concurrent congestive cardiac failure. The mortality rate was elevated among individuals in the HEN group compared to those in the HON, SIAD, or normonatraemic groups. The plasma sodium concentration returned to normal levels in 7 out of 10 patients (70%) by day 7. Among the three patients who continued to experience hyponatremia, underlying bronchiectasis was identified as the cause. Conclusion: In cases of community-acquired pneumonia (CAP), hyponatremia is typically attributed to either the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIAD) or hypovolemia. However, it's important to note that while Hypovolemic Euvolemic Hyponatremia (HEN) is less frequently encountered, it carries a more adverse prognosis. Keywords: Community-acquired pneumonia; Hyponatraemia; SIAD