Inflammation‐Triggered Enlargement of Choroid Plexus in Subacute COVID‐19 Patients with Neurological Symptoms.

Objective: To investigate whether choroid plexus volumes in subacute coronavirus disease 2019 (COVID‐19) patients with neurological symptoms could indicate inflammatory activation or barrier dysfunction and assess their association with clinical data. Methods: Choroid plexus volumes were measured in 28 subacute COVID‐19 patients via cerebral magnetic resonance imaging (MRI), compared with those in infection‐triggered non‐COVID‐19 encephalopathy patients (n = 25), asymptomatic individuals after COVID‐19 (n = 21), and healthy controls (n = 21). Associations with inflammatory serum markers (peak counts of leukocytes, C‐reactive protein [CRP], interleukin 6), an MRI‐based marker of barrier dysfunction (CSF volume fraction [V‐CSF]), and clinical parameters like olfactory performance and cognitive scores (Montreal Cognitive Assessment) were investigated. Results: COVID‐19 patients showed significantly larger choroid plexus volumes than control groups (p < 0.001, η2 = 0.172). These volumes correlated significantly with peak leukocyte levels (p = 0.001, Pearson's r = 0.621) and V‐CSF (p = 0.009, Spearman's rho = 0.534), but neither with CRP nor interleukin 6. No significant correlations were found with clinical parameters. Interpretation: In patients with subacute COVID‐19, choroid plexus volume is a marker of central nervous system inflammation and barrier dysfunction in the presence of neurologic symptoms. The absence of plexus enlargement in infection‐triggered non‐COVID‐19 encephalopathy suggests a specific severe acute respiratory syndrome coronavirus 2 effect. This study also documents an increase in choroid plexus volume for the first time as a parainfectious event. ANN NEUROL 2024;96:715–725 [ABSTRACT FROM AUTHOR]