Session: Poster Abstract Session: Pediatric Infections: Viral
Friday, October 19, 2012
Room: SDCC Poster Hall F-H
  • HHV7poster_OCT_15_2012_IDSA_KSchwartz.pdf (684.5 kB)
  • Background: Human herpesvirus 7 (HHV-7) has been associated with a variety of neurological conditions in case reports and small case series. However, a conclusive pathogenic role has not been established. Our objective is to better elucidate the role of HHV-7 in CNS disease, particularly encephalitis, in children.

    Methods: Retrospective case series of children <18 years of age hospitalized between January 1996 and December 2011 in whom HHV-7 was detected by PCR in the CSF. Most children had a detailed, standardized microbiologic investigation as part of the prospective SickKids Encephalitis Registry. Cases were classified as probable HHV-7 disease, or as due to alternate infectious or non-infectious causes by a multi-disciplinary team.       

    Results: A total of 54 children had HHV-7 detected in their CSF.  HHV-7 was the probable cause in 18 (33%), including 10 with encephalitis and 8 with aseptic meningitis.  Over the 15 year period HHV-7 accounted for 3% of all encephalitis cases (10/330) admitted to SickKids. Of the 10 with HHV-7 encephalitis 5 had a normal outcome, 4 had persistent neurological impairments, and 1 died. In 36 (67%) a more plausible cause of CNS disease than HHV-7 was identified including: (a) Infectious etiologies: enteroviruses (n=3), N. meningitidis (n=1), S. lugdunensis shunt infection (n=1), Borrelia burgdorferi (n=1), VZV (n=2) and M. tuberculosis(n=1), EBV (n=2), parvovirus (n=1), and RSV pneumonia (n=2); (b) non-infectious entities including 13 with demyelinating conditions (ADEM, transverse myelitis, and optic neuritis) and 10 with other conditions (psychosis, anti-NDMAR, dehydration, benign intracranial hypertension, SVT, HLH, and post-IVIG aseptic meningitis.

    Conclusion: This study represents the largest series of patients with HHV-7 detected in the CSF reported to date. Our results provide two important observations:  (1) HHV-7 is associated with CNS disease in some children; (2) Detection of HHV-7 in the CSF is often coincidental and not causally related to clinical disease.  Detection of HHV-7 in CSF should not dissuade clinicians from further investigating children with CNS disease because in the majority of cases its detection is coincidental, likely reflecting latent virus within lymphocytes.  Further study combining CSF PCR with serology may better define the precise role of HHV-7 in CNS disease.

    Kevin Schwartz, MD, Pediatric Infectious Diseases, University of Toronto/The Hospital for Sick Children, Toronto, ON, Canada, Susan E. Richardson, MD, CM, 3 Division of Microbiology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada, Daune MacGregor, MD, Pediatric neurology, The Hospital for Sick Children, Toronto, ON, Canada, Brenda Banwell, MD, Pediatric Neurology, The Hospital for Sick Children, Toronto, ON, Canada, Sanjay Mahant, MD, Pediatrics, The Hospital for Sick Children, Toronto, ON, Canada and Ari Bitnun, MD, MSc, Hosp. for Sick Children, Toronto, ON, Canada


    K. Schwartz, None

    S. E. Richardson, None

    D. MacGregor, None

    B. Banwell, None

    S. Mahant, None

    A. Bitnun, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 17th with the exception of research findings presented at the IDWeek press conferences.