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Updated 13 February 2013

Middle ear infection

Otitis media is an inflammation or infection of the cells lining the middle ear cavity. The middle ear is the area located immediately behind the eardrum.

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Description

  • Middle ear infection (otitis media) is an inflammation or infection of the middle ear.
  • It is the most common cause of earache in children.
  • Otitis media is a very common childhood illness, but can also affect adults.
  • Middle ear infection is typically accompanied by respiratory tract infection, such as colds and flu.
  • Severe untreated ear infections can result in permanent hearing loss.

Otitis media is an inflammation or infection of the cells lining the middle ear cavity. The middle ear is the area located immediately behind the eardrum. Tiny bones inside the middle ear transmit sound signals from the eardrum to the inner ear. Often, otitis media accompanies a common cold, flu or another type of respiratory infection. This is because the middle ear is connected to the upper respiratory tract by passages called the Eustachian tubes, and infection can spread to the middle ear by this route.

Otitis media is in fact two conditions:

  • Ear infection (purulent otitis media): bacteria or viruses cause infection of the middle ear, resulting in accumulation of fluid in the cavity.
  • Fluid behind the eardrum (otitis media with effusion, or serous otitis media): this condition has no symptoms of infection.

Otitis media occurs in various degrees of severity, as follows:

  • Acute otitis media: a single, isolated case that is easily cured.
  • Recurrent otitis media: when the condition clears up but comes back three times in a six-month period, or four times in a year.
  • Chronic otitis media: when the condition persists for weeks without clearing up.

Cause

  • The most common cause of otitis media is an upper respiratory tract viral infection, such as a cold or flu, when viruses infecting the nose and throat travel to the ear. The Eustachian tube becomes so swollen that middle ear ventilation is impaired, the area becomes inflamed and infected and pus accumulates behind the eardrum.
  • Nasal allergies - to pollen, dust, animal dandruff or food - can produce the same effect, as can smoke, fumes and other environmental toxins. The tube can also become blocked with mucus.
  • When air can't reach the middle ear space, a vacuum may be created which results in fluid in the middle ear space (middle ear effusion).
  • Bacteria and/or viruses in the back of the nose and throat may grow in the fluid, causing an ear infection.
  • Among the bacteria most often found in infected middle ears are the same varieties responsible for sinusitis, pneumonia and other upper respiratory infections.

Babies and young children are more likely to get ear infections because:

  • They have shorter, narrower, and more horizontal Eustachian tubes, which can become more easily blocked than those of older children and adults.
  • Their immune systems have not built up defences against previous infections as they have in older children and adults.
  • They have a smaller nasopharynx, the area behind the nose where the Eustachian tubes open. The adenoids are also situated here, and their proximity to the tubes predisposes them to infection.

Symptoms

A middle ear infection may include the following symptoms:

  • A feeling of fullness in the ear
  • Earache: either a sharp, sudden pain or a dull, continuous pain, which may be severe
  • Babies pulling at their ears
  • Fever
  • Drainage from the ear, which is thick and yellow (not normal earwax) and may contain blood, indicating rupture of the eardrum
  • Irritability, difficulty sleeping and decreased appetite in children
  • Nausea and diarrhoea accompanying earache
  • Nasal congestion
  • Dizziness or change in balance
  • Hearing loss in the affected ear
  • A yellow or red and bulging eardrum, visible to a doctor when examining the infected ear with a special instrument called an otoscope
  • Sometimes, if severe purulent otitis media is not treated, the pressure of pus in the middle ear may eventually burst the eardrum. Once this happens, fever usually decreases, ear pain stops, and pus begins to drain into the ear canal.

Fluid (otitis media with effusion) may collect in the middle ear space after an infection or without a prior infection. Symptoms of fluid in the ear are not particularly obvious and may include:

  • Popping, ringing, or a feeling of fullness or pressure in the ear
  • Some loss of hearing - children with hearing loss may seem to not pay attention when you speak to them. Young children who cannot talk may be irritable or have behaviour problems when they experience hearing loss
  • Irritability and disturbed sleep pattern in children
  • A snapping sensation when swallowing, yawning, or blowing the nose
  • An eardrum that looks dull, yellow or red, and does not move as it should when a doctor looks at it with an otoscope

Prevalence

Infection of the middle ear is a very common illness of infancy and early childhood. Two out of three children have at least one episode before the age of three. Almost all children have otitis media at least once before they are seven years old.

Although acute otitis media is not contagious, the upper respiratory tract infection that usually precedes it can be. This infection can easily be transmitted in large crowds and among groups of children in schools and day-care centres.

Course

Ear infections usually occur along with an upper respiratory infection, such as a cold. During an upper respiratory infection, the tissues in the back of the nose and throat swell. The swollen tissues prevent the Eustachian tube, which connects the back of the nose with the middle ear space, from opening up during swallowing, sneezing, and yawning.

When air can't reach the middle ear space because the opening is closed, a vacuum is created which draws fluid from the tissues lining the middle ear into the middle ear space (middle ear effusion). Bacteria and/or viruses that are in the back of the nose and throat may travel up the tube and grow in the fluid, causing an ear infection.

Symptoms of an ear infection (acute otitis media) usually begin two to seven days after an upper respiratory infection.

About 80% of children still have some fluid (which may not be infected) behind the eardrum two weeks after treatment for an ear infection. This is considered normal and in most cases will clear up without treatment. Some children may have fluid behind the eardrum one, two, or three months after an ear infection clears, but the incidence of this decreases over time.

If fluid behind the eardrum lasts longer than 12 weeks, the child may need additional treatment and a hearing test. Babies and children younger than three years are learning how to talk, so hearing evaluation and treatment for persistent fluid behind the eardrum is important for this age group. Fluid can build up behind the eardrum (otitis media with effusion) even if a child hasn't had an obvious cold, ear infection, or other upper respiratory infection.

Ear infections rarely become chronic or present serious risks. However, untreated, otitis media can sometimes lead to more serious complications, such as mastoiditis (a rare inflammation of bone adjacent to the ear). Repeated ear infections can scar the eardrum, causing permanent hearing loss, and may interfere with speech acquisition in children younger than three years old. Also, persistent fluid behind the eardrum can damage it, causing hearing loss.

Risk factors

The following groups have a higher than average risk of otitis media:

  • Children three years and younger
  • Individuals (children especially) who get recurrent colds and upper respiratory infections
  • Children with enlarged adenoids - the swollen adenoid tissue may prevent the Eustachian tube from opening, allowing fluid to build up behind the eardrum
  • Males
  • Caucasians (higher risk than other ethnic groups)
  • Individuals with a family history of ear infections
  • Children whose siblings get ear infections
  • Children in day-care centres
  • People (children especially) living in households with tobacco smokers, or who are frequently exposed to tobacco smoke
  • Children who are bottle-fed rather than breast-fed
  • Children with Down's syndrome
  • Children with cleft palate
  • Children who suffer from allergies
  • People with poor or damaged immune systems

When to see a doctor

Unresolved otitis media can lead to complications, so you should call your doctor immediately if:

  • Your child has earache or a sense of fullness in the ear. This is especially important if your child also has a fever, has recently had an upper respiratory tract infection, or is younger than six months. A fever indicates the possibility of a more serious infection.
  • You or your child frequently develops otitis media; repeated bouts can lead to hearing loss or more serious infections.
  • You or your child has hearing problems; the infection may be affecting hearing ability.

A child who suffers from an especially troublesome ear infection may need to be examined by an otolaryngologist (an ear, nose, and throat specialist).

Diagnosis

If you or your child has an earache accompanied by a stuffy or runny nose, sore throat and fever, it is likely that the problem is otitis media. The physician will use an otoscope (a lighted instrument designed to examine the ear through the ear canal) to look for changes in the external ear canal and eardrum. Changes in the appearance of the eardrum, together with symptoms listed above, indicate fluid build-up and ear infection.

To check for a bacterial infection, a doctor may make an opening in the eardrum and draw out a sample of fluid for culture from the affected middle ear. This more extreme measure is rarely performed, and usually only in the case of very serious or stubborn infections.

Treatment

Home

Serous otitis media usually resolves spontaneously, so no specific therapy is necessary.

It is often possible to provide considerable symptomatic relief for an infected ear at home, with the following methods:

  • Warmth, such as from a warm compress, may provide relief.
  • Steam inhalations and increasing room humidity may help.
  • If you take antihistamines, which may dry out the respiratory passages, increase fluid intake.
  • Gargling with salt water can soothe a sore throat and clear the Eustachian tubes.
  • Holding your head erect and sleeping with the head elevated helps drain the middle ear.
  • Some people find relief with non-prescription decongestants (oral or nasal solutions or sprays). Used for more than three days, however, sprays can become habit-forming and lead to rebound congestion, or a worsening of the original condition.

Up to 80% of children with ear infections get better without treatment. However, most doctors choose to treat ear infections.

Medication

Most doctors attempt to cure middle ear infection before more serious complications set in. Treatment usually involves eliminating the causes of otitis media, killing any invading bacteria, boosting the immune system and reducing Eustachian tube swelling.

To reduce swelling in the Eustachian tubes, decongestants and antihistamines may be prescribed.

To ease the pain, your doctor may recommend an analgesic, which also helps reduce fever. Paracetamol and mefenamic acid is also recommended for discomfort.

Sometimes, even without medical treatment, symptoms of ear infections may go away without medication; therefore, some doctors may recommend watching an infection or persistent middle ear fluid without the use of antibiotics.

However, if the doctor confirms that there is an active middle-ear infection, an antibiotic such as amoxicillin will usually be prescribed. Symptoms usually diminish within 48 to 72 hours of beginning the medication, and the infection should clear up in seven to ten days. The full course of treatment must be followed. If the ear is draining fluid, antibiotic eardrops may also be necessary.

Infants younger than six weeks old may need intravenous antibiotics to treat acute otitis media.

Once the infection is ended, about 40% of children still have some non-infectious fluid inside their middle ears. Although this fluid may cause some lingering hearing loss, it almost always clears up on its own within two weeks to two months. Permanent hearing loss is rare.

If a child's eardrum has ruptured from severe acute otitis media, the ruptured portion usually heals with antibiotic treatment.

A follow-up visit within two weeks is important if symptoms don't go away or when the child is younger than 15 months. If the child is older and the symptoms have disappeared, follow-up may be delayed to four to six weeks.

Surgery

If a case of otitis media develops serious complications, physicians may suggest surgery to eliminate infection, or they may drain the middle ear.

When fluid is present in the middle ear for three months or longer, or there is pronounced hearing loss, myringotomy may be considered. This is a procedure in which a small tube is inserted through the eardrum, allowing fluid to drain from the middle ear and air to enter the middle ear allowing free movement of the eardrum once again.

Children who suffer from frequent bouts of otitis media or who have immune deficiencies may need to take antibiotics for an extended period of time or have a tympanostomy tube placed in the ear. The tympanostomy tube, which is inserted surgically, allows drainage and ventilates the middle ear. However, this procedure is often expensive and may lead to infection and scarring.

If tubes don't end the recurrent ear infections, the removal of adenoids, tonsils or both may be considered.

Prevention

Ear infection is difficult to prevent, but recognising the signs early and getting treatment may preclude more serious problems.

  • Since frequent upper respiratory tract infections can lead to frequent episodes of otitis media, you can reduce the risk of ear infections by reducing risk for the common cold. This would include limiting exposure to large crowds, and encouraging older children to wash their hands often, especially before touching their eyes, nose, or mouth.
  • Second-hand tobacco smoke may increase your child's risk for ear infections, so keep your home smoke-free. Remove as many other environmental pollutants from your home as possible, such as dust, cleaning fluid and solvents.
  • In infants, breast-feeding helps prevent ear infections by passing along immunities and helping the Eustachian tube function properly. If your infant is bottle-fed, do not allow her to lie down with the bottle; this increases the risk for otitis media.

Reviewed by Dr D. Wagenfeld, M.B.Ch.B, M.Med, F.C.S.

 
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