Hemorrhagic Transformation of HSV-1 Encephalitis Presenting as Ischemic Stroke and Discussion of Uncertainties in Clinical Management: A Case Report

Introduction: Herpes simplex virus (HSV) encephalitis is the most common cause of sporadic encephalitis in the USA. Both ischemic and hemorrhagic brain injury are commonly recognized complications of central nervous system (CNS) HSV infections, with radiographic findings such as diffusion restriction that can mimic acute ischemic stroke (AIS). The risk of hemorrhage complicates the use of antithrombotic therapy in patients with HSV encephalitis and concurrent ischemic injury or venous thromboembolic disease. Still, no clear guidelines exist on the use of antithrombotic drugs in patients with HSV encephalitis. Case Presentation: In this case report, we describe a patient with history of stroke who was initially diagnosed with AIS and treated with antiplatelet therapy and venous thromboembolism chemoprophylaxis, later found to have superimposed HSV-1 encephalitis and subsequently developed hemorrhagic transformation. The clinical course, including evolving neurologic deficits, seizure activity, and imaging progression, raised uncertainty as to whether the lesions represented true ischemic infarction, HSV-related cytotoxic injury, or a combination of both. Antithrombotic therapy was continued due to the history of stroke, vascular risk factors, and a concern for concurrent ischemic injury, highlighting competing risks. Conclusion: Hemorrhagic transformation occurring in HSV encephalitis during antithrombotic therapy for suspected AIS is a rarely reported finding in the literature. This case underscores the limitations of applying standard stroke paradigms in CNS infection, where hemorrhagic transformation may reflect disease evolution and causality related to antithrombotic therapy is uncertain.