The role of cerebrospinal fluid levels of neutrophil gelatinase-associated lipocalin (NGAL) and electroencephalography in the assessment of impaired consciousness in the context of infection.

Introduction: The sepsis syndrome is potentially affecting several organs and systems irrespectively of the primary source of the infection. Alterations of the brain function in sepsis patients may result either from a primary central nervous system (CNS) infection or could be part of the sepsis-associated encephalopathy (SAE), a common complication of sepsis, characterized by a diffuse dysfunction of the brain due to an infection elsewhere in the body without overt CNS infection. Aim of the study was to evaluate the usefulness of electroencephalography and the biomarker neutrophil gelatinase-associated lipocalin (NGAL) when measured in the cerebrospinal fluid (CSF) in the management of these patients.

Methods: Patients presenting at the emergency department with altered mental status and signs of infection were included in this study. Among initial assessment and treatment of the patients based on the international guidelines for treating sepsis, NGAL was measured in the cerebrospinal fluid (CSF) using ELISA technique. Electroencephalography was performed when possible within 24 hours after admission and EEG abnormalities were recorded.

Results: 32 of 64 patients included in this study were diagnosed with central nervous system (CNS) infection. CSF NGAL was significantly higher in patients with CNS infection compared to patients without CNS infection (18.1 [5.1-71.1] vs 3.6 [1.2-11.6]; p<0.001). There was a trend for higher CSF NGAL in patients with EEG abnormalities, which did not reach statistical significance (p=0.106). CSF NGAL levels were similar between survivors and non-survivors (medians: 7.04 vs 11.79).

Conclusion: In patients presenting at the emergency department with altered mental status and signs of infection, CSF NGAL was significantly higher in patients with CSF infection. Its role in this acute setting should be evaluated further. CSF NGAL could be suggestive of EEG abnormalities.