Your Family Physician

Introduction

Background

The American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) define acute otitis media as an infection of the middle ear with acute onset, presence of middle ear effusion (MEE), and signs of middle ear inflammation. Acute otitis media most commonly occurs in children and is the most frequent specific diagnosis in children who are febrile. Clinicians, including those in the ED, often overdiagnose acute otitis media.

Bulging of the tympanic membrane is the highest predictive value when evaluating the presence of MEE. Other findings that indicate the presence of MEE include limited mobility of the tympanic membrane with pneumatic otoscopy and fluid visualized behind the tympanic membrane or in the ear canal (with perforation).

Distinguishing between acute otitis media and otitis media with effusion (OME) is important. OME is more common than acute otitis media. When OME is mistaken for acute otitis media, antibiotics may be prescribed unnecessarily. OME is fluid in the middle ear without signs or symptoms of infection. OME is usually caused when the eustachian tube is blocked and fluid becomes trapped in the middle ear. Signs and symptoms of acute otitis media occur when fluid in the middle ear becomes infected.

Recurrent otitis media is defined as 3 episodes of acute otitis media within 6 months or 4 or more episodes within 1 year.

Pathophysiology

Acute otitis media usually arises as a complication of a preceding viral upper respiratory infection (URI). The secretions and inflammation cause a relative occlusion of the eustachian tubes. Normally, the middle ear mucosa absorbs air in the middle ear. If air is not replaced because of relative obstruction of the eustachian tube, a negative pressure is generated and causes a serous effusion. This effusion of the middle ear provides a fertile media for microbial growth, and, with the URI, introduction of upper airway viruses and/or bacteria into the middle ear may occur. If growth is rapid, the patient will have a middle ear infection. If the infection and the resultant inflammatory reaction persist, perforation of the tympanic membrane or extension into the adjacent mastoid air cells may be present.

Frequency

United States

Otitis media is common, with 50% of children having an episode before their first birthday and 80% of children having one by their third birthday. An estimated $3-4 billion are spent each year on care of patients with acute otitis media and related complications.

Mortality/Morbidity

• Mortality is rare in countries where treatment of complications is available, and it is not frequent in countries where treatment is not available.
• Morbidity may be significant for infants in whom persistent MEE develops. MEE leads to hearing deficits and speech delay. Most spontaneous perforations eventually heal, but some persist. Frequent recurrences of acute otitis media are relatively common.
• Otitis is not considered a major source of bacteremia or meningeal seeding, but local brain abscess has been documented, demonstrating that it is possible for acute otitis media to extend.

Race

Otitis media is more frequent in certain racial groups (eg, Inuit and American Indians) than in others.

• Other factors in the environment (eg, crowding, daycare setting, nutrition) may be more important than race, but they have not been fully delineated.
• Otitis media is less common in groups with high rates of breastfeeding than in groups with low rates of breastfeeding.

Sex

Boys are affected more commonly than girls, but no specific causative factors have been found. Male sex is a minor determinant of infection.

Age

• Ear infection occurs in all age groups, but it is considerably more common in children, particularly those aged 6 months to 3 years, than in adults. This age distribution is presumably due to immunologic factors (eg, lack of pneumococcal antibodies) and anatomic factors (eg, a low angle of the eustachian tube with relation to the nasopharynx).
• Children with significant predisposing factors (eg, cleft palate) acquire infections so frequently that some authors advocate the routine placement of polyethylene tubes in their tympanic membranes to maintain aeration of the middle ear.

Clinical

History

Patients who can communicate usually describe feelings of pain or discomfort in the affected ear. However, most cases occur in children who are unable to communicate specific complaints.

• Acute otitis media
  • Earache
  • Fever (not required for the diagnosis)
  • Accompanying or precedent URI symptoms (very common)
  • Decreased hearing
• Acute otitis media in infants
  • Infants may be asymptomatic.
  • Irritability may be the only symptom.
• Serous OME
  
  
  • Patients are usually asymptomatic.
  • Decreased hearing may be demonstrated on audiometry.

Physical

If the canal is clean and if the patient is cooperative, physical examination is easy. If the canal is occluded with cerumen or debris, if the canal is anatomically small, or if the patient is unable to cooperate, examination may be difficult.

• Inflammation of the tympanic membrane and diminished movement of the membrane with insufflation or decreased visibility of the landmarks of the middle ear are the hallmarks of otitis media.
  • Injection of the membrane is common in crying infants, and it may mislead the casual observer to believe the patient has acute otitis media. Therefore, pneumatic otoscopy is helpful in examining any patient with an injected tympanic membrane.
  • A history suggestive of acute otitis media and an ear canal full of purulent exudate is usually considered sufficient to diagnosis acute otitis media with perforation.
  • Acute otitis media should be painless. If pain is present, suspect that a foreign body in the ear canal is causing the infection or that the patient has otitis externa.
• Remove cerumen and other debris from the canal, as necessary, to allow clear visualization of the entire tympanic membrane.
  • Removal may be difficult if the patient is uncooperative.
  • Irrigation may be useful, as it may soften and dislodge cerumen so that it can be removed more easily.
  • Soft plastic curettes are preferred to metal ones, but a firm tool may be necessary to remove a hard block of cerumen.
  • Patients may require a referral if sufficient time and resources are not available for the proper and safe removal of cerumen.
  • Care should be taken to avoid perforation of the tympanic membrane.
• The association between bacterial conjunctivitis and otitis media is well described.
  • Any patient with purulent conjunctival exudate should receive thorough examination of the tympanic membranes.
  • Sinusitis and purulent rhinitis frequently accompany otitis in children and infants.

Causes

Anatomic and immunologic factors in the presence of acute infection are the main causes of acute otitis media.

• Pneumococcus species, Haemophilus influenzae (untypeable), and Moraxella species are the bacteria most commonly involved in otitis media.
• Less common causes are other bacteria, Mycoplasma species, and viruses.
• Sterile effusions occur in approximately 20% of cases studied.
• Risk factors for otitis media have been identified and can generally be divided into those associated with the host and those associated with the environment.
  
  
  • Host risk factors include age, prematurity, race, allergy, craniofacial abnormalities, gastroesophageal reflux, presence of adenoids, and genetic predisposition.
  • Environmental risk factors include upper airway infections, seasonality, daycare, family size, exposure to passive smoking, breastfeeding, socioeconomic level, and use of pacifiers.
  • Upper airway infections may lead to AOM.
  • Incidence is increased in the autumn and winter months.
  • Daycare center attendance increases risk of development of AOM.
  • Bottle-feeding increases the incidence compared with breastfeeding.
  • Pacifier use increases risk for AOM.
  • Smoking in the household clearly increases the incidence of all forms of respiratory problems in childhood.
  • A family history of middle ear disease increases the incidence.
  • Siblings with recurrent AOM is a risk factor.
  • Helicobacter pylori has recently been studied and found in middle ear, tonsillar, and adenoid tissues in patients with OME, indicating a possible role in pathogenesis of OME.
  • Acute otitis media in the first year of life is a risk factor for recurrent acute otitis media.

Source : http://emedicine.medscape.com/article/764006-overview