Central nervous system infection associated with Human herpesvirus 7 presenting with predominant persecutory delusions as initial psychiatric manifestations after allogeneic stem cell transplantation: a rare case report with diagnostic and therapeuti

BACKGROUND: Human Herpesvirus 7 (HHV-7)-associated central nervous system (CNS) infection is an extremely rare complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT), with no prior reports of initial presentation dominated by psychiatric symptoms. CASE PRESENTATION: We report a unique case of a 14-year-old female with high-risk acute lymphoblastic leukemia (ALL) who developed acute persecutory delusions and auditory hallucinations as the sole initial manifestations 54 days post-allo-HSCT. Brain magnetic resonance imaging (MRI) revealed multifocal lesions in the right frontal lobe and bilateral parieto-occipital regions. Metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) confirmed the presence of HHV-7, establishing the diagnosis of HHV-7-associated CNS infection. The patient achieved complete clinical and radiological remission following a comprehensive treatment regimen combining antiviral therapy, glucocorticoids, intravenous immunoglobulin (IVIG), and antipsychotic medication. CONCLUSIONS: This is the first documented case of HHV-7-associated CNS infection post-allo-HSCT presenting with persecutory delusions as the initial symptom, expanding the clinical spectrum of HHV-7-related CNS complications in immunocompromised hosts. Our findings emphasize the importance of considering atypical viral encephalitis in the differential diagnosis of acute psychiatric symptoms post-allo-HSCT and highlight the value of early neuroimaging and CSF mNGS for timely diagnosis and targeted intervention.