Herpes Virus Infections of the Brain Complicating Allogeneic Hematopoietic Stem Cell Transplantation (SCT) (S57.001)

Abstract

Objective: Describe the presentation and management of encephalitis due to herpes viruses in post-transplant patients. Background CNS infections due to herpes viruses are associated with high mortality and transplant rejection rates. The management of encephalitis due to human herpes virus 6 (HHV-6) and cytomegalovirus (CMV) may be unique post SCT. Early reliable diagnosis is challenging but critical for appropriate treatment. Design/Methods: We performed a retrospective chart review of 6 patients, between 2009 and 2011, diagnosed with HHV-6 or CMV encephalitis within 6 weeks post SCT. Results: Three patients had HHV-6 encephalitis, 2 had CMV encephalitis. One patient with HHV-6 in CSF, varicella zoster viremia and cardio-embolic strokes was excluded. There were 3 male and 2 female patients between the ages of 22-60 years. Two patients received umbilical cord SCT, 3 received allogeneic bone marrow SCT for hematologic malignancies and hereditary immune disorders. All patients had altered mental status. Patients with HHV-6 had prominent amnesia, headaches and clinical or subclinical seizures. One patient had poikilothermia and diabetes insipidus due to hypothalamic involvement. Brain magnetic resonance imaging (MRI) within 7 days was normal in all patients, but after 7-10 days showed hyperintensity in the limbic area in HHV-6 affected patients. Patients with CMV encephalitis showed atrophy. CSF showed HHV-6 or CMV by PCR with acellularity and normal protein on initial testing. After 7-10 days, minimally elevated protein ( 3 ) were noted. Intravenous ganciclovir and foscarnet or valacyclovir resulted in subsequent improvement. All patients were alive at 100 days. One patient died after 100 days due to transplant complications. Conclusions: A high clinical suspicion and CSF PCR testing for herpes viruses is important for early diagnosis of encephalitis after HSCT. HHV6 virus infection has characteristic clinical and radiological features distinct from CMV encephalitis. Abnormalities on brain MRI or CSF testing are minimal and delayed. Disclosure: Dr. Bhanushali has nothing to disclose. Dr. Kranick has nothing to disclose. Dr. Inati has nothing to disclose. Dr. Freeman has nothing to disclose. Dr. Battiwalla has nothing to disclose. Dr. Nath has nothing to disclose.