Delirium in Meningitis and Encephalitis: Emergence and Prediction in a 6-Year Cohort

Data regarding delirium in patients presenting with infections of the central nervous system, such as meningitis and/or encephalitis (ME), are scarce. We aimed to determine the frequency and early predictors of delirium in the acute phase of ME.

We assessed clinical, radiologic, and laboratory data of patients with ME at a Swiss academic medical center from 2011 to 2017. The highest Intensive Care Delirium Screening Checklist (ICDSC) score was assessed within 24 hours around lumbar puncture. Multivariable logistic regression was performed to identify predictors of delirium (ICDSC ≥4).

Among 330 patients with ME, infectious pathogens were identified in 41%. An ICDSC >1 was found in 28% with and 19% without identified infectious pathogens. Delirium was diagnosed in 18% with and 14% without infectious pathogens and significantly associated with prolonged in-hospital treatment and mechanical ventilation, more frequent administration of neuroleptics and anesthetics (in 96% with delirium vs 35% without), complications, and less recovery to premorbid functional baseline. Low serum albumin at presentation was the only independent predictor of delirium (area under the receiver-operating curve [AUROC] = 0.792) in patients with pathogens. In patients with infections, the AUROC was smallest for encephalitis (AUROC = 0.641) and larger for patients with meningeal infections (meningitis AUROC = 0.807; meningoencephalitis AUROC = 0.896).

Delirium in the context of ME is seen in almost every fifth patient and linked to prolonged treatment, complications, and incomplete recovery. Among clinical, radiologic, and laboratory parameters, the good calibration and discrimination of low albumin serum concentrations for the prediction of delirium in patients with ME seem promising, especially if meninges are affected.