Development of a prediction rule for diagnosing postoperative meningitis: a cross-sectional study.

OBJECTIVE Diagnosing nosocomial meningitis (NM) in neurosurgical patients is difficult. The standard CSF test is not optimal and when it is obtained, CSF cultures are negative in as many as 70% of cases. The goal of this study was to develop a diagnostic prediction rule for postoperative meningitis using a combination of clinical, laboratory, and CSF variables, as well as risk factors (RFs) for CNS infection. METHODS A cross-sectional study was performed in 4 intensive care units in Medellín, Colombia. Patients with a history of neurosurgical procedures were selected at the onset of febrile symptoms and/or after an increase in acute-phase reactants. Their CSF was studied for suspicion of infection and a bivariate analysis was performed between the dependent variable (confirmed/probable NM) and the identified independent variables. Those variables with a p value ≤ 0.2 were fitted in a multiple logistic regression analysis with the same dependent variable. After determining the best model according to its discrimination and calibration, the ß coefficient for each selected dichotomized variable obtained from the logistic regression model was used to construct the score for the prediction rule. RESULTS Among 320 patients recruited for the study, 154 had confirmed or probable NM. Using bivariate analysis, 15 variables had statistical associations with the outcome: aneurysmal subarachnoid hemorrhage (aSAH), traumatic brain injury, CSF leak, positioning of external ventricular drains (EVDs), daily CSF draining via EVDs, intraventricular hemorrhage, neurological deterioration, age ≥ 50 years, surgical duration ≥ 220 minutes, blood loss during surgery ≥ 200 ml, C-reactive protein (CRP) ≥ 6 mg/dl, CSF/serum glucose ratio ≤ 0.4 mmol/L, CSF lactate ≥ 4 mmol/L, CSF leukocytes ≥ 250 cells, and CSF polymorphonuclear (PMN) neutrophils ≥ 50%. The multivariate analysis fitted a final model with 6 variables for the prediction rule (aSAH diagnosis: 1 point; CRP ≥ 6 mg/dl: 1 point; CSF/serum glucose ratio ≤ 0.4 mmol/L: 1 point; CSF leak: 1.5 points; CSF PMN neutrophils ≥ 50%: 1.5 points; and CSF lactate ≥ 4 mmol/L: 4 points) with good calibration (Hosmer-Lemeshow goodness of fit = 0.71) and discrimination (area under the receiver operating characteristic curve = 0.94). CONCLUSIONS The prediction rule for diagnosing NM improves the diagnostic accuracy in neurosurgical patients with suspicion of infection. A score ≥ 6 points suggests a high probability of neuroinfection, for which antibiotic treatment should be considered. An independent validation of the rule in a different group of patients is warranted.

Primer caso de ehrlichiosis monocítica humana reportado en Colombia / First case of human monocytic ehrlichiosis reported in Colombia

La ehrlichiosis es una infección no reconocida ni sospechada en nuestro medio, sin embargo, ciertas características epidemiológicas hacen que deba pensarse en esta entidad a la hora de abordar a un paciente con un cuadro clínico compatible. Presentamos el caso de un soldado joven con factores de riesgo claros para zoonosis, con fiebre, erupción petequial, trombocitopenia, hepatitis y disfunción orgánica múltiple a quien se le confirmó infección por Ehrlichia chaffeensis por medio de serología luego de descartar infecciones comunes y otras infecciones por vectores. Existen limitaciones en los registros de este tipo de enfermedades pues no son de notificación obligatoria y un alto número cursan de manera subclínica, lo que hace probable un elevado subregistro. La importancia de tener en mente esta condición radica en que el retraso del tratamiento se asocia a mayor incidencia de complicaciones, incluyendo desenlaces fatales.

Human ehrlichiosis is an infection that is neither suspected or recognized in our country. Certain epidemiologic clues should arouse suspicion for this entity when the symptoms are suggestive. We present a case of a young soldier with clear risk factors for zoonotic infection, with fever, a petechial rash, thrombocytopenia, hepatitis and multiple organ failure, for whom a diagnosis of Ehrlichia chaffeensis was confirmed by serology after ruling out common infections and other infections caused by vectors . There are important limitations in documenting these cases, because there is no mandatory public reporting and a significant proportion of these cases are asymptomatic, leading to underdocumentation. It is however, of critical importance to raise awareness about this entitysince delays in treatment portend a higher incidence of complications, including death.