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, η 2 = 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