CHAPTER 87

Otitis Media

Nasser Redjal, MD

Otitis media (OM) is the second most common reason after well-child care for a visit to the pediatrician and the most common reason for which antibiotics are prescribed for children. An estimated 30 million office visits per year are for the evaluation and treatment of OM in the United States. More than 25% of all prescriptions written each year for oral antibiotics were for the treatment of middle ear infections. Many surgical procedures, such as myringotomy with tympanostomy tube placement or adenoidectomy, were performed on children for treatment of recurrent disease. However, a dramatic decline has occurred in the prevalence of OM from the prepneumococcal conjugated vaccine (PCV) 7 era to the post-PCV13 era, from 9.5% of office visits to 5.5%, respectively, and from 826 per 1,000 children to 387 per 1,000 children, respectively. Despite this decline, the primary care physician must have a good understanding of these pediatric conditions, which remain quite common.

Otitis media can be classified into the following 5 categories: acute OM (AOM), OM with effusion (OME), recurrent AOM, chronic OME, and chronic suppurative OM. It is important to distinguish between each of these entities because their presentation and management differ.

Acute OM (ie, acute suppurative or purulent OM) is the sudden onset of inflammation of the middle ear, which is often accompanied by fever and ear pain (ie, otalgia). The clinical findings of inflammation noted on otoscopic examination are bulging of the tympanic membrane (TM), limited or absent mobility of the TM, air-fluid level behind the TM, and otorrhea not resulting from acute otitis externa (Box 87.1). Otitis media with effusion or serous OM is the persistence of nonpurulent middle ear fluid after antimicrobial treatment following resolution of acute inflammatory signs. Fluid may persist for 2 to 3 months but usually resolves within 3 to 4 weeks in 60% of cases. Recurrent OM is defined as frequent episodes of AOM with complete clearing between each episode, although a more specific definition of recurrent OM is 3 new episodes of AOM requiring antibiotic treatment within a 6-month period or 4 documented infections in 1 year. This condition affects approximately 20% of children with a propensity to otitis; such children typically have their first infection at younger than 1 year. Chronic OME, which is also known as serous OM, secretory OM, nonsuppurative OM, mucoid OM, and glue ear OM, is characterized by persistence of fluid in the middle ear for 3 months or longer. The TM is retracted or concave with impaired mobility but without signs of acute inflammation. The affected child may be asymptomatic. The child with chronic OME is at increased risk for developing hearing deficits, speech delay, and learning problems. Chronic suppurative OM implies a non-intact TM (ie, perforation or tympanostomy tube present) with at least 6 weeks of middle ear drainage.

Epidemiology

The prevalence of OM peaks in children 6 to 24 months of age. An additional smaller peak occurs at approximately 4 to 6 years of age. Otitis media is relatively uncommon in older children and adolescents. The condition is more common in boys than girls.

Several epidemiologic risk factors for OM have been identified, including age younger than 2 years; first episode before 6 months; familial predisposition; siblings in the household; low socioeconomic status; infant not breastfed; altered host defenses (ie, acquired or congenital immunodeficiencies); environmental factors (eg, cigarette smoke); child care attendance; and the presence of an underlying condition, such as allergic disease of the upper airway, chronic sinusitis, a cleft palate, or other craniofacial anomalies. Children with Down, Goldenhar, or Treacher Collins syndrome and ciliary dysfunction also are at increased risk for OM. American Indian/Alaska Native individuals have a higher incidence of AOM than whites. Otitis media usually occurs during the winter and early spring, coinciding with peaks in the incidence of viral upper respiratory infections (URIs).

Derived from Lieberthal AS, Carroll AE, Chonmaitree T, et al. The diagnosis and management of acute otitis media. Pediatrics. 2013;131(3):e964–e999.

Worldwide, OM results in an estimated 50,000 deaths per year in children younger than 5 years because of the complications of chronic suppurative OM. Otitis media is estimated to affect 65 million to 133 million individuals worldwide, 60% of whom experience significant hearing loss. Chronic suppurative OM is a rare entity in developed countries, in which most instances of OM are of the acute presentation or with effusion.

Etiology

In general, 50% to 90% of cases of AOM culture are bacterial, 20% to 50% are viral, and 66% are both. Until the widespread immunization of children with PCV, the causative microorganisms for AOM were Streptococcus pneumoniae (25%–50%), non-typable Haemophilus influenzae (15%–30%), and Moraxella catarrhalis (3%–20%). Other less common causative organisms include group A streptococcus, Staphylococcus aureus, α-hemolytic Streptococcus, Pseudomonas aeruginosa, anaerobic bacteria, Mycoplasma pneumoniae, chlamydia, and Mycobacterium tuberculosis. Bullous myringitis has shown a 97% bacterial-positive rate, primarily with S pneumoniae, in contrast to the previous belief that mycoplasma was the causative agent in this condition. Respiratory viruses, such as respiratory syncytial virus, adenovirus, rhinovirus, parainfluenza, coronavirus, and influenza (A and B), also play a role. Respiratory syncytial virus, adenovirus, and coronavirus are associated with an increased rate of AOM, with 50% of children with URI caused by these viruses developing AOM; in contrast, only 33% of patients who have URIs caused by rhinovirus, influenza, parainfluenza, or enterovirus develop AOM. The bacterial pathogens causing AOM in the first 6 weeks after birth are essentially the same as those in older children. However, 10.5% of neonates with AOM have gram-negative bacilli.

Currently, approximately 50% of H influenzae and 100% of M catarrhalis isolated from the upper respiratory tract are positive for β-lactamase, and 15% to 50% (average, 30%) of S pneumoniae are not susceptible to penicillin. The mechanism of penicillin resistance among isolates of S pneumoniae is associated not with β-lactamase production but with an alteration of penicillin-binding proteins. This effect varies widely by geographic location and results in resistance to penicillins and cephalosporins.

Clinical Presentation

Children with AOM often have a history of fever and ear pain. Associated symptoms include URI, cough, vomiting, diarrhea, and nonspecific symptoms, such as decreased appetite, waking at night, generalized malaise, lethargy, and irritability. Purulent otorrhea with minimal ear pain and hearing loss may also occur and signifies rupture of the TM. Fever occurs in approximately 30% to 50% of patients. Temperatures exceeding 40°C (104°F) are uncommon and are suggestive of bacteremia or another complication. Verbal children may report tinnitus, vertigo, and hearing loss; Bell palsy is a rare finding. Nonverbal children may appear ataxic on physical examination.

Pathophysiology

The most important factor in the pathogenesis of OM is abnormal function of the eustachian tube (Figure 87.1). Eustachian tube dysfunction occurs for 2 main reasons: abnormal patency and obstruction of the tube. Obstruction is functional (secondary to collapse of the tube), mechanical (from intrinsic or extrinsic causes), or both. Functional obstruction or collapse of the eustachian tube is common in infants and young children because the tube is less cartilaginous and therefore less stiff than in adults; the tube is also more horizontal and shorter in infants and young children. Additionally, the tensor veli palatini muscle is less efficient in this age group. Extrinsically, the presence of lymphoid follicles (eg, adenoidal enlargement) or, rarely, tumors surrounding the opening of the tube contributes to reflux, aspiration, or insufflation of nasopharyngeal bacteria into the middle ear. Intrinsic mechanical obstruction of the eustachian tube occurs as the result of inflammation secondary to a URI or allergy in patients older than 5 years. Viral infections may occur up to 6 to 12 times per year in children younger than 3 years. Subsequently, viral respiratory infections contribute to eustachian tube dysfunction, resulting in negative middle ear pressure, which occurs in 75% of children who have viral URIs. The presence of a viral URI enhances the ability of bacterial pathogens to adhere to and ascend from the nasopharynx to the middle ear via the eustachian tube. Viruses also can affect the local host immune response by impairing leukocyte function, exposing receptors for bacteria, and decreasing the effectiveness of the mucociliary escalator (Figure 87.1).

Figure 87.1. Relationship of middle ear to external and inner ears.

Hematogenous spread of microorganisms also can result in OM. Less often, primary mucosal disease of the middle ear from allergies or abnormal cilia contributes to OM.

Differential Diagnosis

The most common cause of otalgia is AOM. Other causes include mastoiditis, which is almost always accompanied by OM; otitis externa; and referred pain from the oropharynx, teeth, adenoids, or posterior auricular lymph nodes. A foreign body in the canal can produce similar symptoms. In the child with ear pain, a search for any of these other conditions must be undertaken if the TM appears completely normal.

Evaluation

History

The history should carefully delineate the symptoms of OM and differentiate from those indicating a more serious condition, such as meningitis (Box 87.2).

For the infant or child with a history of persistent or recurrent OM, it is important to discern when the last documented infection occurred and what treatment, if any, was administered. It is also critical to monitor development, particularly speech.

Physical Examination

To diagnose OM, the TM must be completely visualized and its mobility assessed. Occasionally, this may be difficult because of the presence of cerumen or otorrhea. In such cases, diagnosis is made on the basis of the history, and treatment may be initiated without confirmation by physical assessment. In all other cases, the position, color, degree of translucency, and mobility of the TM are evaluated. Classically, in AOM the TM is full, bulging, hyperemic, opaque, or has an air-fluid level, with limited or no mobility. Typically, the light reflex is distorted or absent. In the case of persistent or chronic OM, signs of inflammation usually are absent and the TM may be retracted, with limited or no mobility. Smartphone apps exist that can be used in assessing the mobility of the TM and can assist in diagnosing OM.

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