Acute Otitis Media

last authored: Oct 2009, David LaPierre
last reviewed:

 

 

 

Introduction

Acute Otitis media (AOM) is an infection of the middle ear, normally following blockage of the eustacian tube by infection, pharyngitis, or adenoid hypertrophy. It is usually caused by bacteria, though viruses may also be responsible for sym.ptoms.

 

Otitis media is primarily a disease of children, with incidence peaking between 6-12 months. Over half of children have had an ear infection by age one.

 

normal tympanic membrane

following images: acute otitis media


courtesy of Dr Michael Hawke

A certain diagnosis is made with three criteria:

 

Recurrent AOM occurs in over 10% of the population, and is defined by 3 episodes in 6 months, 4 episodes in 1 year, or 6 or more episodes in the first 6 years of life. Otitis media with fluid collection over 3 months is considered otitis media with effusion.

 

 

 

The Case of Nathan Benstead

Nathan is 15 month-old who had been sick with a runny nose and cough for a week. He appeared to be getting better, but then developed a fever and terrible right ear pain. His mother brought him to the family doctor, concerned about an ear infection.

What should the doctor do?

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Causes and Risk Factors

Bacteria are responsible for up to 70% of infections. The most common pathogens include:

Other less frequent causes include Streptococcus pyogenes.

 

Viral causes include rhinovirus and RSV, and can occur alone or alongside bacteria.

 

Major risk factors for developing AOM include:

 

AOM is more common in males. Other higher risk populations include:

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Pathophysiology

Once blocked, air in the middle ear is absorbed. This creates negative pressure and also draws bacteria up from the nasopharynx into the middle ear. Stasis leads to localized bacterial proliferation, inflammation, pus collection, and symptoms.

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Signs and Symptoms

  • history
  • physical exam

History

Symptoms are quite non-specific in infants, consisting of fever, fussiness, decreased feeding, and ear tugging. Vomiting, nausea, and diarrhea may also occur.

Older children and adults can complain of ear pain and decreased hearing.

Physical Exam

A fever is a telling sign of AOM, but not as much as tympanometry.

Middle ear effusion:

  • loss of landmarks
  • bulging TM
  • opaque, erythematous TM
  • yellow fluid
  • decreased TM mobility
  • air-fluid levels
  • otorrhea if the TM has ruptured (assess quality and smell)

Middle ear inflammation:

  • distinct erythema
  • distinct otalgia

 

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

none usually required

Diagnostic Imaging

none usually required

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Differential Diagnosis

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Treatments

Pain control is a key treatment, with acetominophen and ibuprofen.

 

There is often uncertainty regarding antibiotic treatment of AOM, as 60-80% of children resolve with suppoertive therapy.

Amoxicillin is the first-line antibiotic, used to cover S. pneumoniae. Ceftriaxone can be used as second-line, or in patients with penicillin allergy.

If patient is under 6 months of age, or if follow-up is uncertain, antibiotics should be provided.

 

Ciprodex ear drops are ideal for suppurative otitis media.

Gentamycin should be AVOIDED, as it is ototoxic.

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Consequences and Course

90% of suppurative otitis media heals within months. The remainder results in chronic suppurative otitis media (active, quiescent, inactive)

Chronic inflammation can result in tympanosclerosis (myringsclerosis), or calcified ear drum. THis can result in conductive hearing loss.

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Resources and References

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Topic Development

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