Defining diagnostic approaches and outcomes in patients with inflammatory CSF: A retrospective cohort study.

Objective: Define the etiologies, clinical features, time to diagnosis, and outcomes of patients that present with cerebral spinal fluid (CSF) pleocytosis.

Patients And Methods: This is retrospective cohort study of patients with CSF pleocytosis, defined as WBC count >5 cells/mm in the CSF, from July 2015 to June 2016 at a large tertiary care hospital. The proportion of patients within specific diagnostic categories were analyzed for differences in diagnostic testing and outcomes.

Results: 53% of patients had CSF pleocytosis due to an unknown etiology. The leading known cause of neuroinflammation was CNS infection (n = 43/244, 18%), followed by malignancy (n = 28/244, 11%). Mean time to diagnosis was 125 days in patients with autoimmune neuroinflammation and was 16 days in patients with an infection or malignancy. CSF parameters and peripheral white blood cell counts did not distinguish between categories of disease. The presence of CSF oligoclonal bands or a positive biopsy result most commonly supported a diagnosis of an autoimmune disease or malignancy, respectively. Neuroimaging changes were present in only 44% of infections but were found in 80-90% of other categories of neuroinflammation. Patients presenting with a severe neurologic deficit had 22.29 higher odds of a severe deficit at the last neurologic assessment, and mortality was highest (29%) in patients with malignancy-associated neuroinflammation.

Conclusions: This study to defines general diagnostic categories of neuroinflammatory disease in patients and provides new insight on the value of specific diagnostic testing, time to diagnosis, and outcomes in these patient populations.