Comparison of cerebrospinal fluid lactate with physical, cytological, and other biochemical characteristics as prognostic factors in acute bacterial meningitis / Comparação do lactato no líquido cefalorraquidiano com as características físicas, citológicas e outros marcadores bioquímicos, como fator prognostico nas meningites bacterianas agudas

ABSTRACT Bacterial meningitis (BM) is associated with a high morbidity and mortality. Cerebrospinal fluid (CSF) lactate may be used as a prognostic marker of this condition. We hypothesized that CSF lactate levels would remain elevated in participants who died of acute BM compared with those who recovered from this disease. Objective: To evaluate the potential use of lactate and other CSF biomarkers as prognostic markers of acute BM outcome. Methods: This retrospective, longitudinal study evaluated dynamic CSF biomarkers in 223 CSF samples from 49 patients who fulfilled the inclusion criteria of acute BM, with bacteria identified by CSF culturing. The participants were grouped according to outcome: death (n = 9; 18.37%) and survival (n = 40; 81.63%). All participants received appropriate antibiotic treatment. Results: In the logistic regression model, lactate concentration in the final CSF sample, xanthochromia, and CSF glucose variation between the first and last CSF samples were predictors of a poor outcome (death). In contrast, decrease in CSF white blood cell count and CSF percentage of neutrophils, increase in the percentage of lymphocytes, and normalization of the CSF lactate concentration in the last CSF sample were predictors of a good prognosis. Conclusion: The study confirmed the initial hypothesis. The longitudinal analysis of CSF lactate is an important predictor of prognosis in acute BM.

RESUMO As meningites bacterianas (MB) estão associadas à alta morbidade e mortalidade. O lactato no líquido cefalorraquidiano (LCR) pode ser usado como biomarcador de prognóstico nas MB. A hipótese desse estudo é que os níveis de lactato no LCR se mantém elevados entre pacientes com MB aguda que evoluem para óbito, ao contrário do que ocorre em pacientes com bom prognóstico. Objetivo: Avaliar o uso potencial do lactato e outros marcadores no LCR como indicador de prognóstico na MB aguda. Métodos: Foi realizado um estudo retrospectivo longitudinal da dinâmica dos biomarcadores bioquímicos, celulares e físicos no LCR. Foram analisadas 223 amostras de 49 pacientes com MB aguda com bactérias identificadas por cultura do LCR. Os participantes foram divididos em dois grupos de acordo com o desfecho: óbito (n = 9; 18,37%) e não óbito (n = 40; 81,63%). Todos os participantes receberam antibioticoterapia adequada. Resultados: No modelo de regressão logística, as variáveis que diferiram significativamente entre os dois grupos foram concentração de lactato na amostra final de LCR, xantocromia e variação da concentração de glicose entre a primeira e a última amostra de LCR. A alteração desses fatores indicou desfechos negativos (óbito), enquanto a diminuição do número de leucócitos e da porcentagem de neutrófilos, assim como a normalização da concentração de lactato no LCR foram preditores de bom prognóstico. Conclusão: O estudo confirmou a hipótese inicial. A análise longitudinal do lactato no LCR é um importante preditor de prognóstico na MB aguda.

Could cerebrospinal fluid biomarkers offer better predictive value for spinal cord ischaemia than current neuromonitoring techniques during thoracoabdominal aortic aneurysm repair - a systematic review

Abstract Objective: Cerebrospinal fluid (CSF) drainage is a technique that has significantly reduced the incidence of spinal cord ischaemia (SCI). We present results of a systematic review to assess the literature on this topic in relation to thoracoabdominal aortic aneurysm repair (TAAR). Methods: Major medical databases were searched to identify papers related to CSF biomarkers measured during TAAAR. Results: Fifteen papers reported measurements of CSF biomarkers with 265 patients in total. CSF biomarkers measured included S-100ß, neuron-specific endolase (NSE), lactate, glial fibrillary acidic protein A (GFPa), Tau, heat shock protein 70 and 27 (HSP70, HSP27), and proinflammatory cytokines. Lactate and S-100ß were reported the most, but did not correlate with SCI, which was also the case with NSE and TAU. GFPa showed significant CSF level rises, both intra and postoperative in patients who suffered SCI and warrants further investigation, similar results were seen with HSP70, HSP27 and IL-8. Conclusions: Although there is significant interest in this topic, there still remains a significant lack of high-quality studies investigating CSF biomarkers during TAAR to detect SCI. A large and multicentre study is required to identify the significant role of each biomarker.

Cerebrospinal fluid lactate: a differential biomarker for bacterial and viral meningitis in children / Lactato no líquido cefalorraquidiano: um marcador diferencial para meningite bacteriana e meningite viral em crianças

Abstract Objective: To assess the performance of cerebrospinal fluid (CSF) lactate as a biomarker to differentiate bacterial meningitis from viral meningitis in children, and to define an optimal CSF lactate concentration that can be called significant for the differentiation. Methods: Children with clinical findings compatible with meningitis were studied. CSF lactate and other conventional CSF parameters were recorded. Results: At a cut-off value of 3 mmol/L, CSF lactate had a sensitivity of 0.90, specificity of 1.0, positive predictive value of 1.0, and negative predictive value of 0.963, with an accuracy of 0.972. The positive and negative likelihood ratios were 23.6 and 0.1, respectively. When comparing between bacterial and viral meningitis, the area under the curve for CSF lactate was 0.979. Conclusions: The authors concluded that CSF lactate has high sensitivity and specificity in differentiating bacterial from viral meningitis. While at a cut-off value of 3 mmol/L, CSF lactate has high diagnostic accuracy for bacterial meningitis, mean levels in viral meningitis remain essentially below 2 mmol/L.

Resumo Objetivo: Estudar o desempenho do lactato no líquido cefalorraquidiano como biomarcador para diferenciar a meningite bacteriana da meningite viral em crianças, e definir uma concentração de lactato ótima no líquido cefalorraquidiano que possa ser significativa para a diferenciação. Métodos: Foram estudadas crianças com achados clínicos compatíveis com meningite. O nível de lactato no líquido cefalorraquidiano e outros parâmetros convencionais do líquido cefalorraquidiano foram registrados. Resultados: Em um valor de corte de 3 mmol/L, o lactato no líquido cefalorraquidiano apresentou uma sensibilidade de 0,90, especificidade de 1,0, valor preditivo positivo de 1,0, valor preditivo negativo de 0,963, com uma precisão de 0,972. Os índices de probabilidade positivo e negativo foram 23,6 e 0,1, respectivamente. Para comparação entre a meningite bacteriana e viral, a área abaixo da curva do lactato no líquido cefalorraquidiano foi 0,979. Conclusões: Concluímos que o lactato no líquido cefalorraquidiano possui alta sensibilidade e especificidade na diferenciação da meningite bacteriana da meningite viral. Embora em um valor de corte de 3 mmol/L o lactato no líquido cefalorraquidiano possua alta precisão de diagnóstico da meningite bacteriana, os níveis médios na meningite viral permanecem basicamente abaixo de 2 mmol/L.

Portable lactate analyzer for measuring lactate in cerebrospinal fluid (CSF) and plasma ? method-comparison evaluations / Analisador portátil para dosar lactato no líquido cefalorraquidiano e plasma ? comparação de método

Increased plasma lactate levels can indicate the presence of metabolic disorders in HIV infected individuals. Objective: To determine whether a portable analyzer is valid for measuring cerebrospinal fluid (CSF) and plasma lactate levels in HIV infected individuals. Method: CSF and plasma were collected from 178 subjects. Samples tested by the Accutrend® portable analyzer were compared to those tested by a reference device (SYNCHRON LX® 20). Results: The portable analyzer had in plasma sensitivity of 0.95 and specificity 0.87. For CSF the specificity was 0.95; the sensitivity 0.33; the negative predictive value was 95% and the positive predictive value 33%. Conclusions: These findings support the validity of the portable analyzer in measuring lactate concentrations in CSF that fall within the normal range. The relatively poor positive predictive value indicates that a result above the reference range may represent a “false positive test”, and should be confirmed by the reference device before concluding abnormality. .

O aumento da concentração plasmática dos níveis de lactato pode indicar a presença de distúrbios metabólicos em indivíduos infectados pelo HIV. Objetivo: Determinar a validade do analisador portátil para quantificar os níveis de lactato no líquido cefalorraquidiano (LCR) e plasma em indivíduos infectados. Método: LCR e plasma foram coletados de 178 participantes. As amostras testadas com o analisador portátil Accutrend® e os resultados comparados com aqueles obtidos com o equipamento de referência (SYNCHRON LX® 20). Resultados: O analisador portátil teve, no plasma, sensibilidade de 0,95 e especificidade 0,87. No LCR a especificidade foi 0,95; a sensibilidade 0,33; o valor preditivo negativo foi de 95% e o valor preditivo positivo 33%. Conclusões: Estes dados suportam a validade dos resultados do analisador portátil em concentrações de lactato dentro da faixa normal. Os valores preditivos positivos relativamente baixos indicam que um resultado acima da faixa de referência pode representar um resultado “falso positivo”. .

The cerebrospinal fluid lactate is decreased in early stages of multiple sclerosis

BACKGROUND: The purpose of this study was to investigate if the concentration of lactate can provide additional information for pathologies that need examination of the cerebrospinal fluid (CSF) in their diagnostic controls or protocols. METHODS: A prospective study carried out in the year 2001 at the University Hospital of Bellvitge (Barcelona), on 92 samples of CSF from patients who needed this examination. The concentration of lactate, glucose, and the cell count was determined. One year later, the diagnosis revealed from the previous analyzed samples were sorted into groups according to the diagnosis. RESULTS: In the group with multiple sclerosis (MS) (n = 30), there was a significant decrease in lactate concentration (1.52 +/- 0.19 mmol/L) compared to the control group (1.89 +/- 0.11 mmol/L) (p < 0.001). The glucose concentration remained within the normal range and the cell count was < 4 cell/microL even in the relapses. CONCLUSIONS: In the early stages of MS, the lactate concentration in CSF is decreased and this could be related to alterations in sensitivity observed in those patients. Further studies are needed to evaluate if this lactate concentration is a prognostic indicator of the disease.

Effects of decreased cerebral perfusion pressure on cerebral hemodynamics, brain cell membrane function and energy metabolism during the early phase of experimental Escherichia coli meningitis in the newborn piglet

In this study, we tested the hypothesis that decreased cerebral perfusion pressure (CPP) induces cerebral ischemia and worsen brain damage in neonatal bacterial meningitis. Meningitis was induced by intracisternal injection of 10(9) colony forming units of Escherichia coli in 21 newborn piglets. Although CPP decreased significantly at 8 hr after bacterial inoculation, deduced hemoglobin (HbD), measured as an index of changes in cerebral blood flow by near infrared spectroscopy, did not decrease significantly. In correlation analyses, CPP showed significant positive correlation with brain ATP and inverse correlation with brain lactate levels. CPP also correlated positively with HbD and oxidized cytochrome aa3 (Cyt aa3) by near infrared spectroscopy. However, CPP did not show significant correlation with cerebral cortical cell membrane Na+,K+-ATPase activity, nor with levels of lipid peroxidation products. In summary, decreased CPP observed in this study failed to induce cerebral ischemia and further brain injury, indicating that cerebrovascular autoregulation is intact during the early phase of experimental neonatal bacterial meningitis.