Atlas of pathophysiology, 2 Edition

Part II - Disorders

Sensory Disorders

Otitis media

Otitis media—inflammation of the middle ear—may be suppurative or secretory and acute, persistent, unresponsive, or chronic.

Acute otitis media is common in children; its incidence rises during the winter months, paralleling the seasonal rise in nonbacterial respiratory tract infections. With prompt treatment, the prognosis for acute otitis media is excellent; however, prolonged accumulation of fluid within the middle ear cavity causes chronic otitis media and, possibly, perforation of the tympanic membrane.

Chronic suppurative otitis media may lead to scarring, adhesions, and severe structural or functional ear damage. Chronic secretory otitis media, with its persistent inflammation and pressure, may cause conductive hearing loss. It most commonly occurs in children with tympanostomy tubes or those with a perforated tympanic membrane.

Recurrent otitis media is defined as three near-acute otitis media episodes within 6 months or four episodes of acute otitis media within 1 year.

Otitis media with complications involves damage, such as adhesions, retraction, pockets, cholesteatoma, and intratemporal and intracranial complications, to middle ear structures.

Causes

Suppurative otitis media (bacterial infection)

·   Pneumococci

·   Haemophilus influenzae, most common cause in children under age 6

·   Moraxella catarrhalis

·   Beta-hemolytic streptococci

·   Staphylococci, most common cause in children age 6 or older

·   Gram-negative bacteria

Chronic suppurative otitis media

·   Inadequate treatment of acute otitis episodes

·   Infection by resistant strains of bacteria

·   Tuberculosis (rare)

Secretory otitis media

·   Obstruction of the eustachian tube secondary to eustachian tube dysfunction from viral infection or allergy

·   Barotrauma—pressure injury caused by inability to equalize pressures between the environment and the middle ear:

§  during rapid aircraft descent in a person with an upper respiratory tract infection

§  during rapid underwater ascent in scuba diving

Chronic secretory otitis media

·   Mechanical obstruction—adenoidal tissue overgrowth, tumors

·   Edema—allergic rhinitis, chronic sinus infection

·   Inadequate treatment of acute suppurative otitis media

Pathophysiology

Otitis media results from disruption of eustachian tube patency. In the suppurative form, respiratory tract infection, allergic reaction, nasotracheal intubation, or positional changes allow nasopharyngeal flora to reflux through the eustachian tube and colonize the middle ear.

In the secretory form, obstruction of the eustachian tube promotes transudation of sterile serous fluid from blood vessels in the middle ear membrane.

Signs and symptoms

Acute suppurative otitis media

·   Severe, deep, throbbing pain from pressure behind the tympanic membrane

·   Signs of upper respiratory tract infection (sneezing, coughing)

·   Mild to very high fever

·   Hearing loss, usually mild and conductive

·   Tinnitus, dizziness, nausea, vomiting

·   Bulging, erythematous tympanic membrane; purulent drainage in the ear canal if the tympanic membrane ruptures

Acute secretory otitis media

·   Severe conductive hearing loss—varies from 15 to 35 dB, depending on the thickness and amount of fluid in the middle ear cavity

·   Sensation of fullness in the ear

·   Popping, crackling, or clicking sounds on swallowing or with jaw movement

·   Echo during speech

·   Vague feeling of top-heaviness

Chronic otitis media

·   Thickening and scarring of the tympanic membrane

·   Decreased or absent tympanic membrane mobility

·   Cholesteatoma (cystlike mass in middle ear)

·   Painless, purulent discharge

Diagnostic test results

·   Culture and sensitivity tests of exudate show the causative organism.

·   Complete blood count reveals leukocytosis.

·   Radiographic studies demonstrate mastoid involvement.

·   Tympanometry detects hearing loss and evaluates the condition of the middle ear.

·   Audiometry shows degree of hearing loss.

·   Pneumatic otoscopy reveals decreased tympanic membrane mobility.

Treatment

·   Antibiotic therapy

·   Myringotomy—insertion of polyethylene tube into tympanic membrane

·   Inflation of eustachian tube by performing Valsalva's maneuver several times per day

·   Nasopharyngeal decongestant

·   Aspiration of middle ear fluid

·   Concomitant treatment of underlying cause, such as elimination of allergens, or adenoidectomy for hypertrophied adenoids

·   Treatment of otitis externa

Myringoplasty and tympanoplasty

·   Mastoidectomy

·   Cholesteatoma (requires excision)

P.413

CLASSIFICATION AND COMMON COMPLICATIONS OF OTITIS MEDIA