The model can be used to explore these questions and to test possible therapies, including immunomodulatory drugs and antioxidants, Dr. Griffith said.
Explore This IssueAugust 2014
Daniel Choo, MD, the director of pediatric otolaryngology-head and neck surgery at Cincinnati Children’s Hospital Medical Center, discussed the tricky nature of pediatric hearing loss caused by CMV infection.
There is only a two- or three-week window after birth when a child with hearing loss can have a test considered to be definitive for CMV hearing loss. After that, most become carriers or become infected, and the hearing loss can no longer be considered definitively CMV-related.
Studies out of the University of Alabama at Birmingham (UAB) have shown that treatment with parenteral ganciclovir can rescue hearing in some children, or at least stabilize hearing during their first year of life, Dr. Choo said.
When hearing issues arise later, the question is whether to retreat as a reactivation of CMV or explore other possibilities. “It ends up being a risk-benefit calculation,” Dr. Choo said, involving potential adverse events of antiviral treatment, the severity of the impairment, and the age of the patient. UAB researchers have found that two-thirds of patients either had to have their dose reduced or had to withdraw because of toxic events, most commonly bone marrow suppression.
At the University of Cincinnati, researchers are looking for potential guidance in immunoglobulin G (IgG) assays. “If you can’t test to tell if a child has active CMV infection versus just latent colonization, is there some way we can assay for that?” he said. They’ve found that at about two months after infection, your body generates a low-affinity IgG, and after about four months, you generate high-avidity IgGs. “We might be able to exploit that to determine if these kids are actually acutely infected and can be good targets for antiviral treatment,” Dr. Choo said.
New antivirals with less toxicity and better efficacy are being developed, he added. Additionally, University of Cincinnati researchers are exploring intratympanic delivery of medication, an option that would avoid exposing the entire body to toxicities. They’re also developing nanotechnology for delivery of drugs to the inner ear, he said (Antivir Ther. 2014;19:97-105).
Blake Papsin, MD, MSc, FRCSC, otolaryngologist-in-chief and professor of otolaryngology-head and neck surgery at the University of Toronto, said the algorithm for SNHL at his center does not call for automatic imaging and genetic testing.