Linezolid-associated Hyponatremia in Section Guillain-Barré Syndrome Patients in Intensive Care unit: A Retrospective Analysis

Abstract

Introduction: Guillain-Barré Syndrome (GBS) is a neurological disorder associated with ascending paralysis due to damage to the peripheral nerves by the immune system. Hyponatremia is the most common electrolyte disorder encountered in patients with GBS admitted to the Neurointensive Care Unit (NICU). Hyponatremia is associated with a poor outcome, prolonged hospital stay, and increased hospital cost. Linezolid is an oxazolidinone antibiotic used against gram-positive bacteria. The main adverse effect limiting its use is the development of myelo suppression; however, it can also cause hyponatremia. Aim: To investigate the incidence of hyponatremia in GBS patients treated with linezolid. Materials and Methods: This was a retrospective study conducted in a 14-bedded NICU at the National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India, over a period from January 2017 to January 2018. All patients with GBS who received linezolid therapy were included in the study. Out of 46 admitted patients, 16 received linezolid therapy. Final data were available for 12 patients. Hyponatremia was defined as sodium <134 mmol/L, and severe hyponatremia was defined as sodium <128 mmol/L. Descriptive statistics were used to characterise the data. The Wilcoxon signed-rank test was used to compare sodium levels before and after linezolid therapy. A p-value <0.05 was considered significant. Results: The incidence of hyponatremia was 9 out of 12 (75%). Five out of 12 patients had severe hyponatremia. There was a significant decrease of 11 (7-12) mmol/L in sodium level before and after linezolid therapy (p<0.001). The median days to develop hyponatremia were 3 (2-4) days after initiation of therapy. No mortality was observed in the study population. Conclusion: The incidence of hyponatremia is high in GBS patients treated with linezolid in the NICU. It is imperative to monitor sodium levels at frequent intervals in patients treated with linezolid to recognise and treat hyponatremia.