Middle ear infection is infection of the space immediately behind the eardrum.
Middle ear infections (otitis media) may occur in older children and adults (see Middle and Inner Ear Disorders: Otitis Media (Acute)) but are extremely common between the ages of 3 months and 3 years and often accompany the common cold. Young children are particularly susceptible to middle ear infections for several reasons:
• Differences in the eustachian tube
• Increased susceptibility to infection in general
• Increased exposure to infection
• Use of a pacifier
Other important risk factors include
• Exposure to cigarette smoke
• Family history of frequent ear infections
The eustachian tube connects the middle ear with the nasal passages (see Middle and Inner Ear Disorders: The Eustachian Tube: Keeping Air Pressure Equal) and helps balance air pressure in the middle ear with that in the environment. In older children and adults, the tube is relatively vertical, wide, and rigid, and secretions that pass into it from the nasal passages drain easily. In infants and younger children, the eustachian tube is more horizontal, narrower, less rigid, and shorter. Thus, the tube is more likely to become blocked by secretions and to collapse, trapping the secretions in or close to the middle ear and preventing ventilation of the middle ear (that is, blocking air from reaching it). Also, the secretions may contain viruses or bacteria, which multiply and cause infection. Or viruses and bacteria can move back up the short eustachian tube of infants, causing middle ear infections.
At about the age of 6 months, infants become more susceptible to infection because they lose protection from their mother's antibodies, which they received through the placenta before birth. Breastfeeding appears to partially protect children from ear infections because breast milk contains the mother's antibodies.
Also at about this age, children become more sociable and may acquire viral infections after touching other children and objects, then putting their fingers in their mouth and nose. These infections may in turn lead to middle ear infections. Attendance at childcare centers increases the risk of exposure to the common cold and hence to otitis media.
Using a pacifier may impair the function of the eustachian tube and thus interfere with air reaching the middle ear.
Middle ear infections can resolve relatively quickly (acute), or they can recur or persist over a long time (chronic).
ACUTE MIDDLE EAR INFECTION
Acute middle ear infection is a bacterial or viral infection of the middle ear, usually accompanying a cold.
• Children with ear infections may have a fever and trouble sleeping and may cry, become irritable, and pull on their ears.
• Doctors use a handheld light called an otoscope to check the eardrum for redness or bulging.
• Acetaminophen or ibuprofen can relieve fever and pain, and antibiotics are usually used when children do not get better quickly or get worse.
Acute middle ear infection (also called acute otitis media—see Middle and Inner Ear Disorders: Otitis Media (Acute)) is most often caused by the same viruses that cause the common cold. Acute infection may also be caused by bacteria that sometimes normally reside in the mouth and nose. These bacteria include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. An infection initially caused by a virus sometimes leads to a bacterial infection.
Symptoms
Infants with acute middle ear infections have a fever and trouble sleeping. They cry or become irritable for no reason. They may also have a runny nose, cough, vomiting, and diarrhea. The ear is painful and hearing may be decreased. Infants and children who cannot communicate verbally may pull at their ears. Older children are usually able to tell parents that their ear hurts or that they cannot hear well.
Commonly, fluid accumulates behind the eardrum and remains after the acute infection has resolved. This disorder is called secretory otitis media (see Middle and Inner Ear Disorders: Otitis Media (Secretory)).
Complications: Rarely, acute middle ear infection leads to more serious complications. The eardrum may rupture, causing blood or fluid to drain from the ear. Also, nearby structures may become infected and cause symptoms:
• Infection of the bone surrounding the ear (mastoiditis): Pain
• Infection of the inner ear (labyrinthitis): Dizziness and deafness
• Infection of the tissues surrounding the brain (meningitis) or collections of pus (abscesses) in the brain: Headache, confusion, seizures and other neurologic problems
If infections recur, abnormal skinlike tissue (a cholesteatoma) may grow through the eardrum. A cholesteatoma can damage the bones of the middle ear and cause hearing loss.
Diagnosis
Doctors diagnose acute middle ear infections by looking for bulging and redness of the eardrum with an otoscope. They may need to clean wax from the ear first so they can see more clearly. Doctors may use a rubber bulb and tube attached to the otoscope to squeeze air into the ear to see if the eardrum moves. If the eardrum does not move or moves only slightly, infection may be present.
Treatment
Acetaminophen or ibuprofen is effective for fever and pain.
Many acute middle ear infections resolve without antibiotics. Thus, many doctors use antibiotics, only when children do not improve after a brief period of time or when there are signs that the infection is getting worse. Antibiotics, such as amoxicillin (with or without clavulanate) or trimethoprim plus sulfamethoxazole, may be used.
Preparations that contain decongestants (such as pseudoephedrine) or antihistamines (such as brompheniramine or chlorpheniramine) are not helpful.
Ventilating Tubes: Treating Recurring Ear Infections
Ventilating (tympanostomy) tubes are tiny, hollow plastic or metal tubes that are placed in the eardrum through a small slit. These tubes balance the pressure in the environment with that in the middle ear. Doctors recommend ventilating tubes for children who have had recurring ear infections (acute otitis media) or recurring or persistent collections of fluid in their middle ears (chronic secretory otitis media).
Placement of ventilating tubes is a common surgical procedure, done in a hospital or doctor's office. After the procedure, children usually go home within a few hours. The tubes usually fall out on their own after a few months, although some types stay in for a year or more.
Children with ventilating tubes may wash their hair and go swimming, but some doctors recommend that the children not submerge their head completely in water without using earplugs.
Drainage of fluid from the ears indicates an infection, and the doctor should be notified.
CHRONIC MIDDLE EAR INFECTION
Chronic middle ear infection results from recurring infections that damage the eardrum or lead to formation of a cholesteatoma, which in turn promotes more infection.
For children with chronic ear infection, doctors may recommend daily antibiotics for several months. If infection persists or recurs despite the use of antibiotics, doctors may recommend ventilating (tympanostomy) tubes. If the eardrum is damaged or a cholesteatoma has formed, surgery to repair the eardrum or to remove the cholesteatoma may be done.
Resource: Merck Manual Home Edition