Ear Infections in Children – Acute Otitis Media and Glue Ear
Dr Nirmal Patel & Dr Tobias Pincock
The Hearing Mechanism
In order to understand ear infections, one must have some knowledge of the hearing mechanism (figure 1).
Figure 1 – the hearing mechanism
The External Ear
The external ear consists of the auricle and the external ear canal. These structures collect the sound waves and transmit them to the eardrum.
The Middle Ear
The middle ear lies between the eardrum and the inner ear. This chamber contains three bones of hearing: the malleus (hammer), the incus (anvil) and the stapes (stirrup). Vibrations of the eardrum are transmitted across the middle ear space by these three small ear bones. Movement of the third bone (stapes or stirrup) results in fluid waves in the inner ear.
The middle ear chamber is lined by a membrane similar to the lining of the nose and contains secreting glands and blood vessels. This chamber is connected to the back of the nose by a narrow tube called the Eustachian tube.
The Eustachian tube serves to maintain equalisation pressure between the middle ear chamber and the outside atmosphere, as evidenced by the popping sensation noted in the ear during altitude changes.
A healthy middle ear has air surrounding the three bones of hearing (see figure 2).
The Inner Ear
The inner ear is enclosed in dense bone and contains fluids and the tiny hearing
cells. The inner ear is lined by a delicate transparent membrane supplied by microscopic blood vessels, in this small chamber fluid waves resulting from movement of the stapes are transformed into electrical impulses in the nerve.
What is a Middle Ear Infection?
A middle ear infection is an infection (typically caused by either a virus or bacteria) that blocks the eustachian tube and fills the middle ear with fluid and pus. The infection often causes pain and fever (see Figure 3). The middle ear pressure can build up so much that the ear drum bursts and the pus and blood from the middle ear leaks out of the ear canal (see Figure 4). The bursting of the ear drum often settles the pain and fever.
Middle ear infections are common with 80% of children suffering at least one infection in their childhood. The peak age for infections is between 2 to 4 with the incidence declining after the age of 7 as the Eustachian tube matures and the adenoid tissue shrinks.
Figure 2. A Normal Ear drum
Figure 3. Acute ear infection – note the creamy coloured pus behind the ear drum
Figure 4. A hole in the ear drum with pus leaking out. The ear infection can improve when the ear drum bursts and the pus and blood can leak out.
What is Glue Ear?
Glue ear is a form of chronic middle ear infection where the Eustachian tube is blocked and the middle ear space fills with thick “glue” like fluid. Children with this problem may have had ear infections in the past or alternatively present with hearing loss. The thick glue prevents sound transmission through the middle ear into the inner ear and the patient has temporary deafness. Deafness in school age children in one ear for more than 6 months or both ears for more than 3 months may affect school performance due to poor hearing.
How do I know if my child has a middle ear infection?
Most typically children with ear infections will have fevers, pain in their ears and hearing loss. Other signs include uncontrollable crying, difficulty sleeping, irritability, ear rubbing/ pulling and restlessness in the infant or toddler age group. Children with glue ear often have no pain and present simply with hearing loss.
Treatment of Middle ear infections?
Other measures that may help include avoiding daycare or preschool, avoiding smoking around your child, avoiding bottle feeding your child whilst they are lying flat and keeping your child’s nose clear with saline irrigation (such as paediatric
FESS, available over the counter at your chemist).
When is surgery required for middle ear infections?
Surgery is generally advised for your child most commonly to correct the hearing loss, prevent further ear infections and rarely to treat serious complications of ear infections.
When your child has had proven hearing loss for more than 3 months in two ears, or more than 6 months in one ear then treatment is recommended. If the medical and conservative treatments do not resolve the hearing loss, then surgery is usually recommended to clear the fluid in the middle ear and restore hearing back to normal.
Prevent Ear Infections
If your child is getting frequent ear infections the rarely long term damage can occur to their hearing (or adjacent anatomical structures) such as the brain or the facial nerve ( which is the nerve that moves the face and makes your child smile and frown). Surgery to place grommet (middle ear ventilation) tubes decrease the severity, frequency and intensity of the ear infections. The grommet tubes also allow the doctor to prescribe antibiotic ear drops to treat the ear infection, which may be more effective than syrup antibiotics.
After grommet surgery the infections settle down, but often do not completely go away until your child reaches the age of 7 to 10, when their Eustachian tube matures and allows more air into the middle ear.
Treat Serious Complications of Ear Infections
As you now know, ear infections are very common. Occasionally the infection can spread to the adjacent anatomical structures such as the facial nerve, brain, main vein that drains the brain; or become more complicated and form a collection of pus behind the ear or in the neck (see figure 5). These are serious complications and the treatment involves surgery to clear the pus and usually a grommet to clear the infection from the middle ear.
Figure 5 – A CT scan of a brain and soft tissue abscess around the right ear from a middle ear infection.
What surgery is involved with ear infections? The most common surgery is the placement of grommet tubes. Grommets are plastic tubes that are surgically placed into the ear drum to allow pus to drain from the middle ear, and also to allow air to flow back into the middle ear. As mentioned before the middle ear requires air to remain healthy and the grommets allow this to occur.
Depending on the shape of the grommet they can stay in for as short as a few weeks up to a few years (see figures 6 to 8). As the child grows the skin of the ear drum grows underneath the tube and painlessly lifts the tube out of the ear drum and in time the tubes fall out in the wax.
If your child has any nasal blockage and medicines have not unblocked them, then your surgeon may recommend an adenoidectomy to unblock the nose.
If there is a serious complication of an ear infection, then more complicated ear surgery may be involved to remove the infection. Your surgeon will explain the risks, complications and what to expect in detail if this is the case.
Figure 8 – A long term “T – tube” grommet.
Reproduction in part or whole of this material is restricted by copyright law unless express written permission is granted by the Norwest Ear, Nose and Throat Group.