Otitis Media

Introduction

Otitis media refers to inflammation or infection of the middle ear, a common condition that can affect individuals of all ages, with a higher incidence in children.

It is a spectrum of diseases that includes:

1. Acute otitis media (AOM): A sudden onset of infection or inflammation in the middle ear.
2. Chronic suppurative otitis media (CSOM): Persistent or recurrent inflammation or infection of the middle ear.
3. Otitis media with effusion (OME): Accumulation of fluid in the middle ear without active infection.

It is prevalent in all age groups, with a higher incidence in children, particularly between 6 to 24 months. This article explores the spectrum of otitis media, its etiology, epidemiology, pathophysiology, clinical features, diagnosis, and treatment modalities.

Etiology

Otitis media is a complex condition that results from various factors such as infections, allergies, and environmental elements. The causes and risk factors include:

• Reduced immunity due to immuno-deficiencies like HIV, diabetes, and other similar conditions.
• Abnormalities in mucins gene expression, specifically upregulation of MUC5B
• Anatomic abnormalities of the palate and tensor veli palatini
• Ciliary dysfunction
• Genetic predisposition
• Cochlear implants
• Deficiency of Vitamin A
• Bacterial pathogens, including Streptococcus pneumoniae, Haemophilus influenza, and Moraxella (Branhamella) catarrhalis, are responsible for over 95% of cases.
• Viral pathogens such as respiratory syncytial virus, influenza virus, parainfluenza virus, rhinovirus, and adenovirus
• Allergies
• Lack of breastfeeding
• Exposure to passive smoke
• Exposure to passive smoke
• Lower socioeconomic status
• Family history of frequent AOM in parents or siblings

Epidemiology

Otitis media is a widespread issue that seems to affect males slightly more than females. However, due to varying reporting rates and differences in incidence across geographical regions, it's hard to pinpoint the exact number of cases that occur each year. Typically, otitis media is most common between the ages of six and twelve months and decreases after the age of five.

Statistics show that approximately 80% of children will experience otitis media at least once in their lifetime, and between 80% and 90% of all children will experience otitis media with an effusion before starting school. While it's less common in adults than in children, certain sub-populations are still at risk, such as those with a history of recurrent OM in childhood, cleft palate, immunodeficiency, or immunocompromised status.

Pathophysiology

Otitis media is an inflammation of the middle ear caused by a viral infection of the upper respiratory tract that also affects the mucosa of the nose, nasopharynx, and Eustachian tubes.

The middle ear has a narrow space, and the inflammation obstructs the narrowest part of the Eustachian tube, which leads to a decrease in ventilation. This causes negative pressure to increase in the middle ear and results in exudate from the inflamed mucosa. This leads to the growth of bacterial and viral organisms, which eventually causes suppuration and purulence in the middle ear. Symptoms include a bulging or erythematous tympanic membrane and purulent middle ear fluid. It is important to differentiate otitis media from chronic serous otitis media (CSOM), which presents with thick, amber-colored fluid in the middle ear space and a retracted tympanic membrane on otoscopic examination. Both will yield decreased TM mobility on tympanometry or pneumatic otoscopy.

Children can be predisposed to acute otitis media due to several risk factors, including a previous upper respiratory tract infection, male gender, adenoid hypertrophy, allergy, daycare attendance, environmental smoke exposure, pacifier use, immunodeficiency, gastroesophageal reflux, parental history of recurrent childhood OM, and other genetic predispositions.

Histopathology

Acute purulent otitis media (APOM) is a condition in which the subepithelial space becomes swollen and red due to an infiltration of polymorphonuclear (PMN) leukocytes. As the inflammation progresses, the mucosal tissue undergoes changes and granulation tissue forms. After about five days, the epithelium changes from flat cuboidal to pseudostratified columnar, with the presence of goblet cells.

Serous acute otitis media (SAOM) occurs due to inflammation in the middle ear and eustachian tube, usually caused by venous or lymphatic stasis in the nasopharynx or eustachian tube. Inflammatory cytokines attract plasma cells, leukocytes, and macrophages to the site of inflammation, causing changes to the epithelium. This includes an increase in goblet cells due to hyperplasia of basal cells.

Biopsy for histology is typically not carried out for OM outside of research environments.

Clinical Features

Upper respiratory tract infections or seasonal allergic rhinitis often precede the onset of Acute Otitis Media (AOM) in adults. AOM is typically unilateral and causes ear pain (otalgia) and decreased or muffled hearing. The severity of the pain can range from mild to severe. If the tympanic membrane has ruptured, the patient will experience sudden relief of pain, possibly accompanied by purulent otorrhea.

While dysequilibrium may also occur, it is not a common symptom. Conductive hearing loss, which is usually transient, can be caused by the presence of middle ear fluid. If the patient experiences high fever, severe pain behind the ear, or facial paralysis, it could be a sign of unusual complications.[31]

Diagnosing otitis media in children can be challenging because the signs and symptoms can be non-specific. These symptoms include irritability, headache, disturbed or restless sleep, poor feeding, anorexia, vomiting, or diarrhea, and pulling or tugging at the ears. About two-thirds of patients have a low-grade fever.

The diagnosis of otitis media mainly relies on clinical observations and accompanying signs and symptoms. Lab tests or imaging scans are not necessary. The American Academy of Pediatrics has established guidelines for diagnosing acute otitis media, which involve the presence of moderate to severe bulging of the tympanic membrane or new onset of otorrhea not caused by otitis externa, or mild tympanic membrane bulging with recent onset of ear pain or erythema. These criteria are meant to assist primary care clinicians in making accurate diagnoses and informed clinical decisions, but not to replace their clinical judgment.

The most effective and convenient way to diagnose ear problems is through an otoscopic examination.

Acute otitis media (AOM) may cause reddish or normal tympanic membrane (TM) with fluid present in the middle ear, while suppurative otitis media shows obvious purulent fluid and a bulging TM. If there is swelling in the external ear canal (EAC), significant swelling should be taken as a sign of otitis externa or AOE. AOE requires different treatment from other ear infections. It is essential to examine the TM to ensure it is not ruptured if there is swelling in the EAC. In the case of intact TM, painful and reddish EAC requires treatment with ototopical drops for AOE. Both AOM and AOE may coexist, so it is important to examine the middle ear. Reactive EAC swelling can be assumed in case of TM perforation, and the use of ototopical medication is necessary. Only approved medications such as ofloxacin should be used as other agents can be ototoxic.

Diagnosis

The diagnosis of otitis media should always begin with a physical examination using an otoscope, preferably a pneumatic one.

Laboratory Studies:

Laboratory tests are not usually required. However, if an infant below 12 weeks shows symptoms of fever with no apparent cause except acute otitis media, a thorough sepsis investigation may be necessary. There may be a need for laboratory tests to confirm or rule out any underlying systemic or congenital illnesses.

Imaging Studies:

Imaging studies should only be considered if there is a concern for intra-temporal or intracranial complications. Otherwise, they are not necessary.

1. When a complication of otitis media is suspected, computed tomography of the temporal bones can help identify several potential issues such as mastoiditis, epidural abscess, sigmoid sinus thrombophlebitis, meningitis, brain abscess, subdural abscess, ossicular disease, and cholesteatoma.
2. Additionally, magnetic resonance imaging can be used to detect fluid collections, particularly in the middle ear.

Tympanocentesis:

Tympanocentesis is reserved for extreme or refractory cases. It can improve diagnostic accuracy and guide treatment decisions after the middle ear fluid is removed and cultured to identify pathogens.

Other Tests:

Middle ear effusion can also be evaluated using tympanometry and acoustic reflectometry.

Treatment / Management

Once the diagnosis of acute otitis media is confirmed, the primary objective of treatment is to alleviate pain and address the underlying infection with antibiotics.

Pain relief can be achieved with non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen. The issue of prescribing antibiotics early in otitis media is controversial and may vary depending on the country's guidelines. In Europe, watchful waiting is practiced, but it has not gained widespread acceptance in the United States. However, if evidence of suppurative AOM is present, oral antibiotics should be administered to treat the bacterial infection. High-dose amoxicillin or a second-generation cephalosporin are the first-line agents for this purpose.

If there is a TM perforation, treatment should proceed with ototopical antibiotics that are safe for middle-ear use, such as ofloxacin. This method delivers much higher concentrations of antibiotics without any systemic side effects compared to systemic antibiotics.

When bacterial infection is suspected, high-dose amoxicillin is the recommended antibiotic for ten days in both children and adults who are not allergic to penicillin. Amoxicillin is effective in treating otitis media due to its high concentration in the middle ear.

Systemic steroids and antihistamines do not provide significant benefits and are not recommended.

Patients who have experienced four or more episodes of AOM in the past twelve months should be considered for myringotomy with tube (grommet) placement, according to the guidelines of the American Academy of Pediatrics. Recurrent infections that require antibiotics are clinical evidence of Eustachian tube dysfunction, and placement of the tympanostomy tube allows for ventilation of the middle ear space and maintenance of normal hearing. Moreover, if the patient develops otitis media while a functioning tube is in place, they can be treated with ototopical antibiotic drops instead of systemic antibiotics.

Differential Diagnosis

The differential diagnosis of otitis media encompasses a range of conditions that could potentially cause ear pain.

• Cholesteatoma
• Fever in the infant and toddler
• Fever without a focus
• Hearing impairment
• Pediatric nasal polyps
• Nasopharyngeal cancer
• Otitis externa
• Human parainfluenza viruses (HPIV) and other parainfluenza viruses
• Passive smoking and lung disease
• Pediatric allergic rhinitis
• Pediatric bacterial meningitis
• Pediatric gastroesophageal reflux
• Pediatric Haemophilus influenzae infection
• Pediatric HIV infection
• Pediatric mastoiditis
• Pediatric pneumococcal infections
• Primary ciliary dyskinesia
• Respiratory syncytial virus infection
• Rhinovirus (RV) infection (common cold)
• Teething

Resources

Otitis Media in Infants and Children by Charles D. Bluestone, MD

National Library of Medicine

UpToDate