Evaluation of CSF Physicochemical Analysis in The Diagnosis of CNS Infections in Post-Surgical Patients

Introduction: Central nervous system (CNS) infections in post-surgical patients represent a serious complication with high morbidity and mortality. The physicochemical analysis of cerebrospinal fluid (CSF) is a key diagnostic tool that allows for the evaluation of parameters such as glucose, proteins, and lactate to detect infections. With the development of molecular techniques, such as PCR, the accuracy in pathogen detection has improved. However, there are still questions regarding the reliability of traditional methods compared to these advanced techniques, especially in patients who have received prior antibiotic treatment. Objectives: The primary objective of this study is to evaluate the reliability of the physicochemical analysis of CSF as a diagnostic tool for CNS infections in post-surgical patients and to compare it with alternative methods such as PCR, bacterial cultures, and biological markers. The study aims to determine the sensitivity and specificity of each method to improve diagnostic accuracy in this clinical context. Material and Methods: This study is a systematic literature review that includes studies evaluating the physicochemical analysis of CSF, PCR, and bacterial cultures in post-surgical patients with suspected CNS infection. Scientific databases were used, applying specific inclusion and exclusion criteria to ensure the relevance and quality of the selected studies. Results: The results suggest that although the physicochemical analysis of CSF is useful as an initial tool, it has limitations in terms of sensitivity and specificity in patients who have received antibiotic treatment, with sensitivity ranging between 60% and 70%. In contrast, multiplex PCR offers superior sensitivity and specificity, reaching 92% and 98%, respectively. The combination of methods, including the use of biomarkers such as procalcitonin, improves diagnostic accuracy by 30% compared to traditional physicochemical analysis. Conclusion: The physicochemical analysis of CSF remains useful as an initial test, but its effectiveness is limited in post-surgical patients who have received antibiotic treatment. Combining this analysis with molecular techniques and biomarkers significantly enhances the accuracy and speed of diagnosis, thereby supporting a comprehensive diagnostic approach that optimizes the clinical management of CNS infections in the post-surgical context.