doi: 10.56294/shp202211

REVIEW

Combined diagnosis of CNS infections in the post-surgical setting

Diagnóstico combinado de infecciones del SNC en el contexto postquirúrgico

Leonardo De Souza Ferreira Frasson¹ *, Daniel Chiachiara¹ *

¹Universidad Abierta Interamericana, Facultad de Medicina y Ciencias de la Salud, Carrera de Medicina. Buenos Aires, Argentina.

Cite as: Ferreira Frasson LDS, Chiachiara D. Combined diagnosis of CNS infections in the post-surgical setting. South Health and Policy. 2022; 1:11. https://doi.org/10.56294/shp202211

Submitted: 09-02-2022          Revised: 10-05-2022          Accepted: 13-08-2022          Published: 14-08-2022

Editor: Dr. Telmo Raúl Aveiro-Róbalo

Corresponding Author: Leonardo De Souza Ferreira Frasson *

ABSTRACT

Introduction: central nervous system (CNS) infections following neurosurgical interventions represented a serious, although infrequent, complication. Despite their low incidence, they generated high morbidity and mortality. These infections included meningitis, ventriculitis or brain abscesses, with factors such as the type of procedure and antibiotic prophylaxis being determining factors in their occurrence. Against this background, cerebrospinal fluid (CSF) analysis played a key role in the initial diagnosis.

Development: the physicochemical analysis of CSF made it possible to identify alterations suggestive of infection through parameters such as glucose, proteins, pleocytosis and lactate. However, in patients who had received antibiotic treatment, these values were modified, making diagnosis difficult with conventional methods such as cultures and Gram staining. To overcome these limitations, molecular technologies such as multiplex PCR were introduced, which offered greater sensitivity and made it possible to detect specific pathogens such as Neisseria meningitidis or Streptococcus pneumoniae in less time. However, these tests also presented risks, such as false positives, requiring careful clinical interpretation.

Conclusions: CSF physicochemical analysis continued to be useful, but insufficient as the only diagnostic tool. Combination with molecular methods increased the accuracy and speed of diagnosis, allowing more timely treatment. Consequently, it was concluded that the most effective approach was integrated diagnosis, which combined traditional techniques with molecular testing within an appropriate clinical framework.

Keywords: Cerebrospinal Fluid; Neurosurgery; Diagnosis; Infection; CRP.

RESUMEN

Introducción: las infecciones del sistema nervioso central (SNC) posteriores a intervenciones neuroquirúrgicas representaron una complicación grave, aunque poco frecuente. A pesar de su baja incidencia, generaron una elevada morbilidad y mortalidad. Estas infecciones incluyeron meningitis, ventriculitis o abscesos cerebrales, siendo factores como el tipo de procedimiento y la profilaxis antibiótica determinantes en su aparición. Frente a este panorama, el análisis del líquido cefalorraquídeo (LCR) desempeñó un papel fundamental en el diagnóstico inicial.

Desarrollo: el análisis fisicoquímico del LCR permitió identificar alteraciones sugestivas de infección mediante parámetros como la glucosa, proteínas, pleocitosis y lactato. Sin embargo, en pacientes que habían recibido tratamiento antibiótico, estos valores se vieron modificados, dificultando el diagnóstico con métodos convencionales como los cultivos y la tinción de Gram. Para superar estas limitaciones, se introdujeron tecnologías moleculares como la PCR multiplex, que ofrecieron mayor sensibilidad y permitieron detectar patógenos específicos como Neisseria meningitidis o Streptococcus pneumoniae en menor tiempo. No obstante, estas pruebas también presentaron riesgos, como los falsos positivos, exigiendo una interpretaciónclínica cuidadosa.

Conclusiones: el análisis fisicoquímico del LCR continuó siendo útil, pero insuficiente como única herramienta diagnóstica. La combinación con métodos moleculares incrementó la precisión y rapidez del diagnóstico, permitiendo un tratamiento más oportuno. En consecuencia, se concluyó que el enfoque más eficaz fue el diagnóstico integrado, que combinó técnicas tradicionales con pruebas moleculares dentro de un marco clínico adecuado.

Palabras clave: Líquido Cefalorraquídeo; Neurocirugía; Diagnóstico; Infección; PCR.

INTRODUCTION

Central nervous system (CNS) infections represent one of the most feared complications in the post-surgical neurological context. Although their frequency is low, with an incidence ranging from 0,8 % to 7 % according to different studies, their clinical impact is considerable due to the high morbidity and mortality they entail.^(1,2) These infections can manifest themselves in various forms, such as meningitis, ventriculitis, or brain abscesses, and their occurrence is related to multiple factors such as the type of neurosurgical procedure, the use of invasive or minimally invasive techniques, and the effectiveness of preventive measures, including antibiotic prophylaxis.^(3,4) Given the severity of these infections, early and accurate diagnosis is crucial to initiate effective treatment and improve the patient’s prognosis.

In this context, cerebrospinal fluid (CSF) analysis has established itself as a fundamental tool in evaluating CNS infections. Parameters such as glucose, proteins, pleocytosis, and lactate allow us to guide the diagnosis and differentiate between bacterial and non-bacterial infections. However, interpreting these values is not always conclusive, especially in patients who have received previous antibiotic treatment, which can alter the results of conventional cultures.^(5,6)

Incorporating molecular technologies, such as multiplex polymerase chain reaction (PCR), has revolutionized the diagnostic approach, allowing rapid and specific detection of pathogens such as Neisseria meningitidis or Streptococcus pneumoniae.^(7,8) These techniques increase diagnostic sensitivity and are helpful when traditional microbiological tests are negative or unclear. However, the use of molecular tests also has limitations, such as the risk of false positives and the need for careful interpretation of the results in an appropriate clinical context.^(9,10)

Despite technological advances, the diagnostic utility of CSF physicochemical analysis in post-surgical patients with suspected CNS infection still needs to be further evaluated. The present work aims to analyze whether such assessment continues to be a reliable tool on its own or whether it needs to be systematically complemented with modern molecular techniques to achieve greater diagnostic accuracy in these complex patients.

DEVELOPMENT

Central nervous system (CNS) infections in post-surgical patients constitute serious complications with low frequency but high morbidity and mortality. Their incidence varies between 0,8 % and 7 %, regardless of the type of neurosurgical process, invasion, infection prevention, antibiotic prophylaxis, open approach, and minimally invasive. Infections may present as meningitis, brain abscesses, and ventriculitis; therefore, timely diagnosis is key for rapidly implementing effective treatments.^(1,2)

Cerebrospinal fluid (CSF) analysis is a fundamental diagnostic tool in case of CNS infection. Glucose, protein, pleocytosis, and lactate levels can be assessed, which are valuable in discriminating bacteria from aseptic infections. The increased sensitivity of CSF analysis is reflected in the increasing use of molecular technologies, including multiplex PCR, which enables the detection of specific pathogens, such as Neisseria meningitidis or Streptococcus pneumoniae, facilitating faster diagnosis in post-surgical patients.⁽²⁾ CSF analysis, in combination with these technologies, proves to be extremely valuable in the case of previous antibiotic treatment, which modifies the results of conventional cultures. On the other hand, CSF physicochemical diagnosis has many limitations.⁽³⁾

Although Gram stains and cultures remain the standard, a Gram-negative does not exclude infection, and interpretation of molecular results is sometimes difficult, with the implication of possible false positives. Despite these weaknesses, advances in the latest molecular tests, especially in the postoperative setting, have shown that they can significantly shorten the diagnostic time, allowing earlier therapeutic approaches.^(2,3)

In sum, this work attempts to explore whether CSF physicochemical assessment is really a reliable diagnostic tool in post-surgical patients with suspected CNS infection and whether it is comparable to other complementary methods.

CONCLUSIONS

Central nervous system (CNS) infections in the post-surgical setting represent a significant clinical challenge, both because of their low incidence and the high morbidity and mortality involved. Despite advances in surgical techniques and preventive measures, these infections remain a considerable threat to neurologically operated patients. Early diagnosis is essential in this scenario to improve prognosis and guide effective therapeutic decisions. Traditionally, physicochemical analysis of cerebrospinal fluid (CSF) has been a critical tool for identifying these infections, allowing the detection of alterations compatible with infectious processes, such as decreased glucose, increased protein, presence of pleocytosis, and elevated lactate levels.

However, although this analysis continues to be very useful, it has certain limitations, especially in patients previously treated with antibiotics, where the results can be altered, making it challenging to interpret cultures and conventional tests such as Gram staining. In these cases, new diagnostic technologies, such as multiplex polymerase chain reaction (PCR), have made it possible to overcome some of these barriers. These molecular tests offer greater sensitivity and specificity, allowing pathogens to be detected quickly and accurately, even when traditional techniques are negative or inconclusive.

Despite their benefits, molecular tests also require careful interpretation, as they can yield false positives if not correlated adequately with the patient’s clinical context. Therefore, the most comprehensive and practical diagnostic approach combines CSF physicochemical analysis with modern molecular tools, integrating the data obtained into a thorough clinical evaluation.

In conclusion, while traditional CSF analysis retains its relevance as an initial diagnostic tool, it cannot be considered entirely reliable in the post-surgical setting. The incorporation of molecular techniques such as multiplex PCR complements and enhances the diagnostic process, reducing the time needed to identify the causative agent and facilitating the early initiation of targeted treatment. Therefore, adopting a multidisciplinary and complementary diagnostic approach is suggested, which optimizes diagnostic accuracy and contributes to better clinical outcomes in patients with suspected CNS infection after neurological surgery.

BIBLIOGRAPHIC REFERENCES

1. McClelland WS, Hall WA. Postoperative central nervous system infection: incidence and associated factors in 2111 neurosurgical procedures. Clin Infect Dis. 2007 Jul 1;45(1):55-9.

2. Rodrigues GH. Cerebrospinal fluid analysis: current diagnostic methods in central nervous system infectious diseases. Arq Neuropsiquiatr. 2022;80(4):290-4.

3. Castellazzi M, Candeloro R, Pugliatti M, Govoni M, Silvagni E, Bortoluzzi A. Cerebrospinal fluid analysis in rheumatological diseases with neuropsychiatric complications and manifestations: a narrative review. Diagnostics (Basel). 2024 Jan;14(1):2-12.

4. Gastón IM, Quintero P, Murillo E. Infecciones del sistema nervioso central en urgencias. An Sist Sanit Navar. 2008;31(2):99-113.

5. Farina JC, Álvarez CM, Cabañes CA, Cabral WS, Marín SM. Infecciones postneuroquirúrgicas. Puesta al día y recomendaciones intersociedades. 2019 Dec;1-9.

6. Rath PM, Schoch B, Adamzik M, Steinmann E, Buer J, Steinmann J. Value of multiplex PCR using cerebrospinal fluid for the diagnosis of ventriculostomy-related meningitis in neurosurgery patients. Infection. 2014 Dec;42(6):621-7.

7. Julián-Jiménez A, Flores Chacartegui M, Palomo de Los Reyes MJ, Brea-Zubigaray S. Utilidad de la procalcitonina y la proteína C reactiva en las meningitis agudas en urgencias. Neurología. 2013;28(3):189-90.

8. Jin M, Khan AI. Procalcitonin: uses in the clinical laboratory for the diagnosis of sepsis. Lab Med. 2010;41(3):173-7.

9. Wang H, Zhou C, Fu Y. Factors influencing procalcitonin in the cerebrospinal fluid of patients after neurosurgery and its diagnostic value for intracranial infection. BMC Neurol. 2023 Aug;23(1):275.

10. Morales Casado MI, Moreno Alonso F, Juárez Belaunde AL, Heredero Gálvez E, Talavera Encinas O, Julián-Jiménez A. Capacidad de la procalcitonina para predecir meningitis bacterianas en el servicio de urgencias. Neurología. 2016;31(1):9-17.

FINANCING

None.

CONFLICT OF INTEREST

The authors declare that there is no conflict of interest.

AUTHORSHIP CONTRIBUTION

Conceptualization: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Data curation: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Formal analysis: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Research: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Methodology: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Project Management: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Resources: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Software: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Supervision: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Validation: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Visualization: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Writing - original draft: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.

Writing - proofreading and editing: Leonardo De Souza Ferreira Frasson, Daniel Chiachiara.