Explore this issue:April 2015
Panel moderator Michael Seidman, MD, director of otologic and neurotologic surgery and director of the Otolaryngology Research Laboratory at the Henry Ford Health System in Detroit, said history is full of stories of things thought to be impossible that ended up becoming a reality. “It’s critical that we innovate, because there are obviously reasons that we need to,” he said. “There are different ways of doing things.”
Genotype to predict hearing loss. Daniel Choo, MD, director of pediatric otolaryngology–head and neck surgery at Cincinnati Children’s Hospital, said a pediatric patient’s genotype can be used to much greater effect than imaging in predicting hearing loss. “What we saw in our [Pendred syndrome] PDS [gene] mutation patients,” he said, “is that if you have two mutations—so, if you’re homozygous for abnormal pathologic Pendred mutations—first, you start off with worse hearing. But, whatever hearing you have, you have a much greater chance of progressive hearing loss over time.”
This information can be useful in considering cochlear implants. “We’ll have a much lower threshold. As soon as that other ear starts showing a hearing loss … we’ll start that cochlear implant discussion a little earlier,” he said. “It’s probably easier to rehabilitate that child with one ear implant in while there’s still some functional hearing in the other ear, rather than wait until the other ear completely bottoms out.”
Gene mutations and codeine. There is an FDA black box warning for codeine prescriptions for children under the age of nine. Even a typical dose of codeine, which the body converts to morphine, can be overmetabolized, causing a level of morphine in the serum that can suppress the respiratory system.
Physicians can now test for genetic variants that carry a predisposition for this overmetabolizing, Dr. Choo said, so patients, especially young children, can be tested before they are prescribed narcotic pain medications, to minimize risks of overdose and respiratory suppression.
Gentamicin and genetic testing. Mutations in mitochondrial DNA will predispose a person to high sensitivity to the antibiotic gentamicin. Just one dose can cause gentamicin-induced hearing loss, and it’s not a dose-dependent reaction.