eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Middle Ear & Mastoid

Middle Ear, Inflammatory Diseases

Author: Nasir Aziz, MA, George Washington University School of Medicine
Coauthor(s): Diego Preciado, MD, PhD, Assistant Professor, George Washington University School of Medicine, Department of Otolaryngology, Division of Pediatric Otolaryngology, Children's National Medical Center; Sanjeev Silva, MBBS, MRCS, DLO, Senior House Officer, Department of Otorhinolaryngology, Head and Neck, Facial Plastics, Great Ormond Street Hospital for Sick Children, London
Contributor Information and Disclosures

Updated: Jun 14, 2007

Introduction

Background

Inflammatory diseases of the middle ear include a broad range of pathological conditions, including acute otitis media (AOM; suppurative or nonsuppurative), bullous myringitis, granular myringitis, eosinophilic otitis media, and chronic suppurative otitis media (CSOM), with or without cholesteatoma. The range and complexity of the problems that can arise pose a challenge to the clinician, who sometimes has only subtle clues that lead to the discovery of extensive disease.

AOM is characterized by a short-lived infection (<3 mo) that may be initially viral and then bacterial in origin. Patients generally experience pain and some hearing loss and often develop a fever. Discharge from the ear usually accompanies this infection in patients with acute suppurative otitis media.

CSOM has traditionally been classified into safe ear disease and unsafe ear disease. Safe ear disease, sometimes called tubotympanic disease, is characterized as a central perforation of the pars tensa with the inflammatory process affecting the mucosa of the middle ear cleft. Unsafe ear disease, sometimes called atticoantral disease, is typified by a marginal perforation of the posterosuperior pars tensa or pars flaccida. Cholesteatoma is frequently present in CSOM with posterosuperior perforations. Partially due to induced bony erosion and secondary infection, cholesteatomas can lead to potentially devastating sequelae. Admittedly, all cases of CSOM, including those described above as safe, can be associated with serious intracranial complications. Therefore, the term safe does not adequately categorize any cases of CSOM.

CSOM can be more simply divided into mucosal disease and cholesteatoma. Mucosal disease is typified by a bacterial infection of the middle ear cleft with the presence of pus, associated with discharge through a pars tensa perforation, for longer than 3 months. Acquired cholesteatoma, usually arising from the pars flaccida skin, typically involves the epitympanum and the mastoid antrum and, as stated above, can be erosive, causing serious complications.

Eosinophilic otitis media is an intractable middle ear disease associated with bronchial asthma and nasal allergy that sometimes induces deterioration of sensorineural hearing loss. How eosinophils accumulate in the middle ear has yet to be determined; active eosinophilic inflammation may occur in the entire respiratory tract, including the middle ear, in patients with this disease. EOM often produces a yellow and highly viscous middle ear effusion and can cause symptoms that range from prolonged hearing loss and otorrhea to sudden deafness. The middle ear symptoms are unresponsive to conventional treatments for otitis media and are instead treated with steroids.¹

Pathophysiology

The ciliated, pseudostratified columnar epithelium of the respiratory tract extends up the eustachian tube as far as the anterior part of the middle ear cavity. Because of the presence of goblet cells and mucus-secreting glands, this epithelium is capable of mucus production. More posteriorly, the mucosa changes patchily into a simple cuboidal or stratified epithelium with no secretory elements. The medial aspect of the tympanic membrane and the mastoid air cells are lined by a single layer of cells that range in shape from cuboidal to flat.

In the early stages of inflammation, regardless of cause, vasodilatation of the submucosal tissues occurs. Glandular secretion is stimulated with the production of a thin mucoid fluid. Some epithelial cells die, and bacteria that are usually in the area multiply in the denuded areas and aggravate the condition. The neutrophils in the blood cause a polymorphonuclear reaction, resulting in a mucopurulent discharge. This discharge may remain stagnant within the middle ear and the mastoid air cell system because of immobility or loss of the cilia, including those in the eustachian tube.

Resolution frequently occurs, but, if the condition is prolonged for some reason, such as the inability of the secretions to drain down the eustachian tube, the number of glands and goblet cells increases, and the areas formerly covered by a cuboidal or flat epithelium change into areas of a similar but perhaps less well-differentiated pseudostratified columnar epithelium. Differentiation into squamous epithelium, most frequently nonkeratinized, can also occur.

Granulation tissue results from the nonresolution of an inflammatory process. Localized areas of the mucosa become hyperplastic with invasion of fibroblasts, capillaries, macrophages, plasma cells, and lymphocytes. Granulation tissue can be covered by all the mucosal types described above, but, because the tissue is frequently ulcerated, it does not have a mucosal covering.

Anatomical considerations also contribute to the pathophysiology of middle ear diseases. The eustachian tube is important in pressure regulation of the middle ear, protection from nasopharyngeal sound pressure and secretions, and clearance (into the nasopharynx) of secretions produced within the middle ear. The eustachian tube has been found to be highly compliant in infants and young children, providing the eustachian tube with an abnormal patency. Greater patency of the eustachian tube allows not only gas to readily flow from the nasopharynx into the middle ear but also easier access for unwanted secretions from the nasopharynx. This increases the likelihood of infection.

The length of the eustachian tube is another key anatomical consideration in the pathogenesis of middle ear inflammatory disorders. The shorter the tube, the more likely secretions can reflux into the middle ear. For instance, young children with a cleft palate and those with Down syndrome have eustachian tubes that are statistically shorter than those of age-matched controls younger than 6 years, which may explain the frequent occurrence of troublesome otorrhea in these populations.

Various chemical mediators of inflammation have been described and categorized into the following groups:

• Histamine
• Lipid mediators
• Plasma enzyme systems
• Kinins
• Cytotoxins
• Neurogenic substances

Frequency

United States

One third of all antibiotics purchased for children are for the treatment of otitis media.²

The Center for Disease Control (CDC) showed that otitis media was the principal diagnosis for 12% of ambulatory-care visits provided to children younger than 15 years.

AOM accounts for 24 million pediatric office visits and $5 billion in costs annually.

A study of cholesteatoma in the United States revealed an incidence of 6 cases per 100,000 population. Within this population, cholesteatoma was most common in children aged 10-19 years, with an incidence of 9.2 cases per 100,000 population.

International

Over the last 20 years, the incidence of AOM increased by 68% in Finland, while that of repeat AOM increased by 39% in the United States. In developed countries, the current prevalence of secretory otitis media (SOM) is 20% in infants. In the United Kingdom, the incidence of active CSOM in the adult population was reported to be 0.6%. An Israeli study estimated the annual incidence of CSOM in children (birth to age 15 y) to be 39 cases per 100,000 population.

Mortality/Morbidity

Since the advent of the antimicrobial era, the mortality rate associated with complications of middle ear inflammatory disorders has dramatically decreased. The mortality rates associated with otitis media and mastoiditis decreased from about 2 per 100,000 persons in 1936 to less than 0.01 per 100,000 persons in 1976.

The 2 most common complications of suppurative otitis include mastoiditis and facial paralysis. In developing nations, these complications remain relatively common because of the lack of adequate primary care. According to studies in developing countries, the rate in some communities was as high as 33% for perforation of the tympanic membrane, 6% for otorrhea, and 5% for mastoiditis.

Cholesteatoma, atticoantral mucosal disease, and acute suppurative otitis media cause complications by spread of infection.

Complications of CSOM are associated with high morbidity and may be life threatening. In a retrospective study, Browning calculated that the risk of a patient with CSOM developing an intracerebral abscess is 1 in 3500.³

Extracranial complications include chronic otitis externa and meatal stenosis, ossicular discontinuity due to ossicular erosion, middle ear adhesions, tympanosclerosis, otosclerosis, mastoid tip (Bezold) abscess, lower motor neuron facial nerve palsy, serous or purulent labyrinthitis, petrositis, Gradenigo syndrome, and labyrinthine fistula. All of these represent significant morbidity to the patient.

Intracranial complications include lateral (transverse and sigmoid) sinus thrombosis; meningitis; extradural, subdural, or intracerebral (cerebellar and temporal lobe) abscess; and otitic hydrocephalus. In a study of patients with chronic middle ear disease and cholesteatoma, 7.5% developed intracranial complications. The most common complication was meningitis.

Race

American Indians and Canadian Inuits have a strikingly high incidence of acute suppurative otitis media. In children of African and Australian Aboriginal origin, middle ear infections are more commonly severe. African American children seem to have fewer episodes of middle ear infections than American white children.

CSOM suppurative otitis media without cholesteatoma is extremely common in certain racial groups, including American Indians, Canadian Inuits, Alaskan Inuits, Australian Aborigines, and New Zealand Maoris.

In racial groups with a high incidence of central tympanic membrane perforations, such as North American Inuits and Australian Aborigines, cholesteatoma is relatively uncommon.

Sex

In most studies on the incidence of acute suppurative otitis media, little difference exists between males and females.

Age

• AOM falls into 2 distinct age groups; it is more common in the younger group (0-5 y) than in the older group (5-11 y). By age 6 months, about 25% of all children have had 1 or more episodes of AOM. At age 1 year, this figure rises to 62%; by age 3 years, to 81%; and by age 5 years, to 91%. After age 7 years, the incidence declines.
• The combined results of selected published studies on CSOM showed a bimodal prevalence curve with peaks of 20% at age 2 years and 15% at age 5 years.

Clinical

History

The earliest clinical manifestation of acute suppurative otitis media  is a sense of fullness in the ear with some conductive hearing loss. An earache may be present but is not severe.

In the exudative stage, the middle ear fills with an exudate, which is under pressure. Marked otalgia and fever are also present. In smaller children, anorexia, vomiting, and diarrhea may occur. Conductive hearing loss is noticeable. If the infection progresses, the tympanic membrane may perforate, initially producing hemorrhagic discharge and then mucopurulent discharge. The otalgia usually reduces after perforation.

The 2 classic symptoms of chronic suppurative otitis media (CSOM; mucosal disease) include otorrhea and hearing loss, which can affect one or both ears. The discharge varies in character, from serous or mucoid to frankly purulent, and the discharge may be intermittent or continuous. Blood-stained discharge is found in association with florid granulation tissue and aural polyps, and it is a common indicator of underlying cholesteatoma. 

The predominant form of hearing loss associated with chronic middle ear disease is conductive in nature. More recently, the occurrence of sensorineural hearing loss in the ears with chronic discharge has been recognized. This hearing loss, which mainly involves high frequencies, is thought to result from the passage of bacterial toxins across the round window membrane to the cochlea.

The main symptom of CSOM with cholesteatoma is purulent otorrhea, with or without associated conductive hearing loss, similar to that of mucosal disease alone. Signs found during physical examination coupled with radiologic imaging findings are critical for the diagnosis of cholesteatoma because history symptoms are largely unreliable for determining the presence of cholesteatoma.

Physical

Otoscopic examination in patients with AOM reveals a hyperemic, opaque, bulging tympanic membrane. Pneumatic otoscopy demonstrates reduced mobility. Mucopurulent otorrhea is a reliable sign.

When the diagnosis of otitis media with effusion (OME) is questionable, tympanometry can be beneficial in the examination of infants older than 4 months. Alternatively, acoustic reflectometry with spectral gradient analysis may also be used because it costs less and does not require an airtight seal in the ear canal.

Examination with an operating microscope and adequate suction equipment is required for CSOM diagnosis. In young children, a short-acting, general anesthetic is sometimes required, especially when suction is needed.



In ears without cholesteatoma, the perforation is usually of the central type. Perforations vary in size, and the activity of the disease relates to the degree of discharge. The discharge may be mucoid or purulent. Microbiological swabs should be obtained to identify aerobic and anaerobic pathogens. Pulsatile purulent discharge occurs in heavily infected cases with capillary engorgement of the middle ear mucosa.

If the size of the perforation permits, various middle ear structures can be visualized. The middle ear mucosa is either normal or edematous, and aural polyps may be present, arising from the middle ear mucosa or the margins of the perforation. The most common ossicular abnormalities include disruption of the incudostapedial joint, necrosis of the incus long process, and medial retraction and shortening of the malleus handle. Other features include secondary otitis externa in ears with profuse discharge and scars in patients who have previously undergone otologic surgery.

The hearing loss should be assessed clinically using Rinne and Weber tuning fork tests.

In patients with CSOM with cholesteatoma, the site and the extent of the tympanic membrane defect and the presence and the extent of squamous epithelium and keratin debris should be noted. The involvement of the ossicular chain and the presence of inflammatory polyps, granulation tissue, or osteitis should also be noted.



Rigid lens otoscopy is particularly useful in assessing the extent of cholesteatoma.

The use of angled endoscopes permits examination of the facial recess and the sinus tympani, which is often involved in pars tensa cholesteatoma.

Postnasal space masses can block the orifices of the eustachian tube and cause otitis media. Therefore, an examination of an adult with unilateral otitis media must include a postnasal evaluation with flexible fiberoptic nasopharyngoscopy.

Causes

• Acute otitis media (AOM) prevalence varies by season, with an increased incidence in the colder months.



• Daycare is a major risk factor in the incidence of middle ear infections. Upper airway hygiene in children who attend daycare is poor, and coughing, sneezing, and nasal dripping contaminate the environment with bacteria and viruses.



• Anatomical variants, such as of the overt and submucous cleft palate, may cause recurrent episodes, often with subsequent complications.



• Immunologic deficiencies and functional changes (eg, barotrauma, patulous eustachian tube) have an important influence on the incidence of middle ear infections.



• Adenoid hypertrophy may be an important factor in the etiology of recurrent attacks, possibly because of its close relationship to the eustachian tube.



• Passive smoking has been shown to be associated with the occurrence of otitis media, especially in preschool-aged children whose parents smoke.
• Allergic rhinitis in children has been shown to be associated with higher prevalence of otitis media with effusion (OME). Inflammatory obstruction of the nasopharynx may lead to inflammatory swelling of the eustachian tube with resultant obstruction. This facilitates a reflux of bacteria-laden allergic nasopharyngeal secretions that can then enter the middle ear cavity to cause repeated bouts of otitis media.
• Gastroesophageal reflux disease has also been recently implicated in the pathogenesis of OME. A recent study revealed higher concentrations (up to 1000-fold greater than serum levels) of pepsin/pepsinogen in children with OME. Although direct mechanistic causation has not been shown, the authors concluded that reflux of gastric juice into the middle ear may be the primary factor in the initiation of OME in children.  
• Several studies have attempted to determine a genetic link to recurrent otitis media. A recent study examined the frequency of otitis media in infants hospitalized with respiratory syncytial virus (RSV) infection and found that a certain interferon gamma (IFN-γ) polymorphism may represent one member of a family of genes that contributes to the measured heritability of otitis media. Rates of otitis media are significantly concordant in monozygotic twins.

• Search for CME/CE on This Topic »

• Middle Ear, Eustachian Tube, Inflammation/Infection (Otolaryngology and Facial Plastic Surgery)
• Middle Ear Function (Otolaryngology and Facial Plastic Surgery)
• Middle Ear Endoscopy (Otolaryngology and Facial Plastic Surgery)
• Middle Ear, Mastoiditis (Otolaryngology and Facial Plastic Surgery)

• Researchers Test Stem Cells From Fat Tissue for MS
• PAS 2009: AAP Guidelines for Acute Otitis Media May Encourage Overtreatment
• FDA Updates Warnings for TNF Blockers and Cancer Risk

• Hypovitaminosis D Among Rheumatology Outpatients in Clinical Practice
• C-reactive Protein: The Underlying Cause of Microvascular Dysfunction in Rheumatoid Arthritis
• Suppression of Tumour Necrosis Factor Production From Mononuclear Cells by a Novel Synthetic Compound, CLX-090717

• Otitis Media Resource Center