HHV-7 encephalitis following allogeneic hematopoietic stem cell transplantation: A case report and literature review

Human herpesvirus 7 (HHV-7) encephalitis commonly occurs in immunocompromised individuals and has a poor prognosis. We here reported 3 cases of HHV-7 encephalitis following allogeneic hematopoietic stem cell transplantation (allo-HSCT) with typical neurological symptoms, including altered consciousness and epileptic seizures, and conducted a systematic review of the literature to identify clinical characteristics and management strategies in these patients. Cerebrospinal fluid next-generation sequencing (NGS) was the key evidence that led to their diagnosis. Foscarnet and cidofovir appeared effective, particularly with at least four weeks of treatment. All three patients showed at least partial improvement in neurological symptoms. Furthermore, a systematic search was conducted in PubMed, Google Scholar, and Web of Science to identify related cases. Clinical presentation, diagnostic findings, treatment strategies, and outcomes were analyzed. A total of 10 publications were included, together with our 3 cases, comprising 7 cases of HSCT recipients for detailed analysis. Our study suggested that early recognition and prompt antiviral therapy are critical for improving prognosis. Further exploration is needed regarding risk factors and treatment strategies.