Hearing Loss

Some degree of deafness is common for both severely affected and attenuated people with MPS I. It may be made worse by frequent ear infections. It is important that individuals with MPS I have their hearing checked regularly so that problems can be treated early to maximize their ability to learn and communicate.

Courtesy of the National MPS Society

Deafness in people with MPS I may be conductive deafness, sensorineural deafness, or both.

• Conductive deafness: In order for the middle ear to work properly, the pressure behind the eardrum has to be the same as that in the outer ear canal and the atmosphere. This pressure is equalized by the Eustachian tube, which runs to the middle ear from the back of the throat. If the tube is blocked, the pressure behind the eardrum will drop and the drum will be drawn in. If this negative pressure persists, fluid from the lining of the middle ear will build up and, over time, become thick like glue. This is called middle ear effusion. Following a light general anesthetic, a small incision through the eardrum can be made (myringotomy) to remove the fluid by suction. A small ventilation tube may then be inserted to keep the hole open and allow air to enter from the outer ear canal until the Eustachian tube starts to work properly again. The tubes placed in the eardrum may quickly fall out. If this happens, the surgeon may decide to use tympanostomy tubes (T-tubes), which may stay in place much longer. The goal of this procedure (once the ventilation tube is in place) is to allow the fluid to drain out and improve hearing.
• Sensorineural (nerve) deafness: In most cases, the cause of nerve deafness is damage to the tiny hair cells in the inner ear. It may be found along with conductive deafness, in which case it is referred to as mixed deafness. In most cases, nerve or conductive deafness can be managed with a hearing aid or aids.

Ear infections

Otitis media (OM) is the medical term for an infection of the middle ear. OM is a common problem for children, and is one of the more stubborn problems for children with MPS I. Children with MPS I tend to have many ear infections that can be very difficult to treat. For some individuals with MPS I, a number of middle ear infections may occur before MPS I is diagnosed.

In children without MPS I, ear infections are usually caused by blockage of the eustachian tubes (the tube that runs from the middle ear to the throat and helps equalize the pressure in the middle ear) due to large adenoids or problems with drainage of fluid from the middle ear. In children with MPS I, this is also complicated by the buildup of the GAG in the middle ear, nose, mouth, and throat.

Antibiotics are the usual treatment for otitis media. Some common side effects of antibiotics include diarrhea, nausea and vomiting. They may also cause skin rashes and allergic reactions. Occasionally, older children may have infections caused by other bacteria (such as Pseudomonas aeruginosa or Staphylococcus aureus) that can be more difficult to treat. If the child has tympanostomy tubes, ear drops may be used to treat the infection. Corticosteroid medications (which reduce inflammation) may also be helpful.