Otitis Media – Causes, Symptoms, Diagnosis, Treatment

Otitis media is a group of inflammatory diseases of the middle ear. The two main types are acute otitis media (AOM) and otitis media with effusion (OME). AOM is an infection of rapid onset that usually presents with ear pain. In young children, this may result in pulling at the ear, increased crying, and poor sleep.^[rx] Decreased eating and fever may also be present.^[rx] OME is typically not associated with symptoms.^[rx] Occasionally a feeling of fullness is described.^[rx] It is defined as the presence of non-infectious fluid in the middle ear for more than three months.^[rx]

Acute otitis media is defined as an infection of the middle ear space. It is a spectrum of diseases that include acute otitis media (AOM), chronic suppurative otitis media (CSOM), and otitis media with effusion (OME). Acute otitis media is the second most common pediatric diagnosis in the emergency department following upper respiratory infections. Although otitis media can occur at any age, it is most commonly seen between the ages of 6 to 24 months.[rx]

Infection of the middle ear can be viral, bacterial, or coinfection. The most common bacterial organisms causing otitis media are Streptococcus pneumoniae, followed by non-typeable Haemophilus influenzae (NTHi), and Moraxella catarrhalis. Following the introduction of the conjugate pneumococcal vaccines, the pneumococcal organisms have evolved to non-vaccine serotypes. The most common viral pathogens of otitis media include the respiratory syncytial virus (RSV), coronaviruses, influenza viruses, adenoviruses, human metapneumovirus, and picornaviruses.[rx][rx][rx]

Pathophysiology

Otitis media begins as an inflammatory process following a viral upper respiratory tract infection involving the mucosa of the nose, nasopharynx, middle ear mucosa, and Eustachian tubes. Due to the constricted anatomical space of the middle ear, the edema caused by the inflammatory process obstructs the narrowest part of the Eustachian tube leading to a decrease in ventilation. This leads to a cascade of events resulting in an increase in negative pressure in the middle ear increasing exudate from the inflamed mucosa and buildup of mucosal secretions, which allows for the colonization of bacterial and viral organisms in the middle ear. The growth of these microbes in the middle ear then leads to suppuration and eventually frank purulence in the middle ear space. This is demonstrated clinically by a bulging or erythematous tympanic membrane and purulent middle ear fluid. This must be differentiated 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.

Several risk factors can predispose children to develop acute otitis media. The most common risk factor is a preceding upper respiratory tract infection. Other risk factors include male gender, adenoid hypertrophy (obstructing), allergy, daycare attendance, environmental smoke exposure, pacifier use, immunodeficiency, gastroesophageal reflux, parental history of recurrent childhood OM, and other genetic predispositions.[15][16][17]

Types of Otitis Media

• Acute otitis media (AOM) – When the term “ear infection” is used it usually refers to acute otitis media. AOM is characterized by rapid onset and relatively short duration. AOM is generally viral in nature but can also be bacterial (acute bacterial otitis media).
• Serous otitis media (SOM) or Otitis media with effusion (OME) – SOM typically follows an episode of AOM. The buildup of fluid that is secreted from the inflamed mucous membrane can be temporary with no signs of infection. Serous otitis media is a common childhood condition that is often known as “glue ear”.
• Chronic otitis media with effusion – Occasionally serous otitis media can become chronic (present for 6 weeks or longer). Although there is no infection present, the fluid remains in the middle ear for a prolonged period of time or returns repeatedly. The longer the fluid remains in the middle ear the more viscous the fluid becomes.
• Chronic suppurative otitis media – If the doctor makes a diagnosis of chronic suppurative otitis media, he or she has found that a long-term ear infection resulted in tearing of the eardrum. This is usually associated with pus draining from the ear.

Causes of Otitis Media

Otitis media is a multifactorial disease. Infectious, allergic, and environmental factors contribute to otitis media.[rx][rx][rx]

• Bottle-feeding – The position of the breastfeeding child is better than that of the bottle-feeding position in terms of the function of the Eustachian tube that leads into the middle ear. If an infant needs to be bottle-fed, it’s better to hold babies rather than allowing them to lie down with the bottle. Ideally, they should not take the bottle to bed. (In addition to increasing the chance for acute infection, falling asleep with milk in the mouth enhances the risk of tooth decay.)
• Upper respiratory tract infection – Children often develop upper respiratory infections prior to developing this type of infection. Exposure to groups of children (as in childcare centers) results in more frequent colds, and therefore more earaches.
• Exposure to air with irritants – such as tobacco smoke
• Birth defects – Children with a cleft palate or Down syndrome are more prone to ear infections.
• Eustachian tube problems – Any problems with the Eustachian tubes (for example, blockage, malformation, inflammation) will increase the risk of infection. If the individual has allergies, he or she may have swelling and blockage of one or both Eustachian tubes.
• Immunosuppressed – Individuals with suppressed immune responses are at increased risk for ear infections.
• Ear infections later in childhood – Children who have episodes of acute infections before six months of age tend to have more later in childhood.

These causes and risk factors include

• Decreased immunity due to human immunodeficiency virus (HIV), diabetes, and other immuno-deficiencies
• Genetic predisposition
• Mucins which include abnormalities of this gene expression, especially upregulation of MUC5B
• Anatomic abnormalities of the palate and tensor veli palatini
• Ciliary dysfunction
• Cochlear implants
• Vitamin A deficiency
• Bacterial pathogens, Streptococcus pneumoniae, Haemophilus influenza, and Moraxella (Branhamella) catarrhalis, are responsible for more than 95%
• Viral pathogens such as respiratory syncytial virus, influenza virus, parainfluenza virus, rhinovirus, and adenovirus
• Allergies
• Lack of breastfeeding
• Passive smoke exposure
• Daycare attendance
• Lower socioeconomic status
• Family history of recurrent AOM in parents or siblings

Risk factors for ear infections include

• Age – Children between the ages of 6 months and 2 years are more susceptible to ear infections because of the size and shape of their eustachian tubes and because their immune systems are still developing.
• Group child care – Children cared for in group settings are more likely to get colds and ear infections than are children who stay home. The children in group settings are exposed to more infections, such as the common cold.
• Infant feeding – Babies who drink from a bottle, especially while lying down, tend to have more ear infections than do babies who are breast-fed.
• Seasonal factors – Ear infections are most common during the fall and winter. People with seasonal allergies may have a greater risk of ear infections when pollen counts are high.
• Poor air quality – Exposure to tobacco smoke or high levels of air pollution can increase the risk of ear infections.
• Alaska Native heritage – Ear infections are more common among Alaska Natives.
• Cleft palate – Differences in the bone structure and muscles in children who have cleft palates may make it more difficult for the eustachian tube to drain.

Symptoms of Otitis Media

The primary symptom of acute otitis media is ear pain; other possible symptoms include fever, reduced hearing during periods of illness, tenderness on a touch of the skin above the ear, purulent discharge from the ears, irritability, and diarrhea (in infants). Since an episode of otitis media is usually precipitated by an upper respiratory tract infection (URTI), there are often accompanying symptoms like a cough and nasal discharge.^[rx] One might also experience a feeling of fullness in the ear.

The typical signs to watch for include

• Tugging or pulling at the ear(s)
• Loss of appetite
• Unsettledness and crying
• Trouble sleeping
• High fever
• Discharge from the ears
• Problems with balance
• Trouble hearing, especially soft sounds or when being spoken to from behind

Infants and children may have one or more of the following symptoms

• crying
• irritability
• sleeplessness
• pulling on the ears
• ear pain
• a headache
• neck pain
• a feeling of fullness in the ear
• fluid drainage from the ear
• a fever
• vomiting
• diarrhea
• irritability
• a lack of balance
• hearing loss

Common signs and symptoms in adults include

• Ear pain
• Drainage of fluid from the ear
• Trouble hearing

Diagnosis of Otitis Media

Otitis media is diagnosed clinically via objective findings on physical exam (otoscopy) combined with the patient’s history and presenting signs and symptoms. Several diagnostic tools are available such as a pneumatic otoscope, tympanometry, and acoustic reflectometry to aid in the diagnosis of otitis media. Pneumatic otoscopy is the most reliable and has a higher sensitivity and specificity as compared to plain otoscopy, though tympanometry and other modalities can facilitate diagnosis if pneumatic otoscopy is unavailable.

History and Physical

• Although one of the best indicators for otitis media is otalgia, many children with otitis media can present with non-specific signs and symptoms, which can make the diagnosis challenging. These symptoms include pulling or tugging at the ears, irritability, headache, disturbed or restless sleep, poor feeding, anorexia, vomiting, or diarrhea. Approximately two-thirds of the patients present with fever, which is typically low grade.\
• The diagnosis of otitis media is primarily based on clinical findings combined with supporting signs and symptoms as described above. No lab test or imaging is needed. According to guidelines set forth by American Academy of Pediatrics, evidence of moderate to severe bulging of the tympanic membrane, or new onset of otorrhea not caused by otitis externa or mild tympanic membrane (TM) bulging with recent onset of ear pain or erythema is required for the diagnosis of acute otitis media. These criteria are intended only to aid primary care clinicians in the diagnosis and proper clinical decision making but not to replace clinical judgment.[rx]
• The otoscopic examination – should be the first and most convenient way of examining the ear and will yield the diagnosis to the experienced eye. In AOM the TM may be erythematous or normal, and there may be fluid in the middle ear space. In suppurative OM there will be obvious purulent fluid visible and a bulging TM. The external ear canal (EAC) may be somewhat edematous, though significant edema should alert the clinician to suspect otitis externa (outer ear infection, AOE), which may be treated differently. In the presence of EAC edema, it is paramount to visualize the TM to ensure it is intact. If there is an intact TM and a painful, erythematous EAC, to topical drops should be added to treat AOE. This can exist in conjunction with AOM or independent of it, so visualization of the middle ear is paramount. If there is a perforation of the TM then the EAC edema can be assumed to be reactive, and ototopical medication should be used, but an agent approved for use in the middle ear, such as ofloxacin, must be used, as other agents can be ototoxic.[rx][rx][rx]

Evaluation

The diagnosis of otitis media should always begin with a physical exam and the use of an otoscope, ideally a pneumatic otoscope.[rx][rx]

Laboratory Studies

• Laboratory evaluation is rarely necessary. A full sepsis workup in infants younger than 12 weeks with fever and no obvious source other than associated acute otitis media may necessary. Laboratory studies may be needed to confirm or exclude possible related systemic or congenital diseases.

Imaging Studies

Imaging studies are not indicated unless intra-temporal or intracranial complications are a concern.[rx][rx] When an otitis media complication is suspected, computed tomography of the temporal bones may identify mastoiditis, epidural abscess, sigmoid sinus thrombophlebitis, meningitis, brain abscess, subdural abscess, ossicular disease, and cholesteatoma.

• Magnetic resonance imaging – may identify fluid collections, especially in the middle ear collections.
• Tympanocentesis – Tympanocentesis may be used to determine the presence of middle ear fluid, followed by culture to identify pathogens – Tympanocentesis can improve diagnostic accuracy and guide treatment decisions but is reserved for extreme or refractory cases.[rx][rx]
• Tympanometry – During a tympanometry test, your child’s doctor uses a small instrument to measure the air pressure in your child’s ear and determine if the eardrum is ruptured.
• Reflectometry – During a reflectometry test, your child’s doctor uses a small instrument that makes a sound near your child’s ear. Your child’s doctor can determine if there’s fluid in the ear by listening to the sound reflected back from the ear.
• Acoustic reflectometry. This test measures how much sound is reflected back from the eardrum — an indirect measure of fluids in the middle ear. Normally, the eardrum absorbs most of the sound. However, the more pressure there is from fluid in the middle ear, the more sound the eardrum will reflect.

Other Tests

Tympanometry and acoustic reflectometry may also be used to evaluate for middle ear effusion.[rx]

• In more severe cases, such as those with associated hearing loss or high fever, audiometry, tympanogram, temporal bone CT and MRI can be used to assess for associated complications, such as mastoid effusion, subperiosteal abscess formation, bony destruction, venous thrombosis or meningitis.^[rx]
• Acute otitis media in children with moderate to severe bulging of the tympanic membrane or new onset of otorrhea (drainage) is not due to external otitis. Also, the diagnosis may be made in children who have mild bulging of the eardrum and recent onset of ear pain (less than 48 hours) or intense erythema (redness) of the eardrum.
  To confirm the diagnosis, middle-ear effusion and inflammation of the eardrum have to be identified; signs of these are fullness, bulging, cloudiness, and redness of the eardrum.^[rx]
• It is important to attempt to differentiate between acute otitis media and otitis media with effusion (OME), as antibiotics are not recommended for OME.^[rx] It has been suggested that bulging of the tympanic membrane is the best sign to differentiate AOM from OME, with a bulging of the membrane suggesting AOM rather than OME.^[rx]

The following conditions come under the differential diagnosis of otitis media[rx][rx][rx]

• 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

Treatment of Otitis Media

Once the diagnosis of acute otitis media is established, the goal of treatment is to control pain and to treat the infectious process with antibiotics.

• Non-steroidal anti-inflammatory drugs (NSAIDs) – such as acetaminophen, can be used to achieve pain control. There are controversies about prescribing antibiotics in early otitis media, and the guidelines may vary by country as discussed above.
• Antibiotics – If there is clinical evidence of suppurative AOM, however, oral antibiotics are indicated to treat this bacterial infection, and high-dose amoxicillin or a second-generation cephalosporin are first-line agents. If there is a TM perforation, treatment should proceed with topical antibiotics safe for middle-ear use such as ofloxacin, rather than systemic antibiotics, as this delivers much higher concentrations of antibiosis without any systemic side-effects.[rx] Amoxicillin has good efficacy in the treatment of otitis media due to its high concentration in the middle ear. In cases of penicillin allergy, the American Academy of Pediatrics (AAP) recommends azithromycin as a single dose of 10 mg/kg or clarithromycin (15 mg/kg per day in 2 divided doses). Other options for penicillin-allergic patients are cefdinir (14 mg/kg per day in 1 or 2 doses), cefpodoxime (10 mg/kg per day, once daily), or cefuroxime (30 mg/kg per day in 2 divided doses). Those patients whose symptoms do not improve after treatment with high dose amoxicillin, high-dose amoxicillin-clavulanate (90 mg/kg per day of amoxicillin component, with 6.4 mg/kg per day of clavulanate in 2 divided doses) should be given. In children who are vomiting or if there are situations in which oral antibiotics cannot be administered, ceftriaxone (50 mg/kg per day) for three consecutive days either intravenously or intramuscularly is an alternative option. Systemic steroids and antihistamine have not been shown to have any significant benefit.[rx][rx][rx]
• Acetaminophen or nonsteroidal anti-inflammatory drugs – have been proven to be adequate for mild to moderate pain. Also, opioids (e.g., oxycodone or hydrocodone) are recommended for severe pain and should be prescribed in a limited amount since symptoms for uncomplicated OE should improve within 48 hours of initiating topical antibiotic therapy. If there is no improvement in pain within 48 to 72 hours, a reassessment by a primary care physician is strongly recommended.[rx]

Common topical antibiotics indicated for otitis externa include:

• Polymyxin B, neomycin, and hydrocortisone 3 to 4 drops to the affected ear four times a day
• Ofloxacin 5 drops to the affected ear twice daily
• Ciprofloxacin with hydrocortisone 3 drops to the affected ear twice daily
• Ear tubes – If your child has certain conditions, your child’s doctor may recommend a procedure to drain fluid from the middle ear. If your child has repeated, long-term ear infections (chronic otitis media) or continuous fluid buildup in the ear after an infection cleared up (otitis media with effusion), your child’s doctor may suggest this procedure. During an outpatient surgical procedure called a myringotomy, a surgeon creates a tiny hole in the eardrum that enables him or her to suction fluids out of the middle ear. A tiny tube (tympanostomy tube) is placed in the opening to help ventilate the middle ear and prevent the buildup of more fluids. Some tubes are intended to stay in place for six months to a year and then fall out on their own. Other tubes are designed to stay in longer and may need to be surgically removed.
• Anesthetic drops – These may be used to relieve pain as long as the eardrum doesn’t have a hole or tear in it.

Surgery

• Patients who have experienced four or more episodes of AOM in the past twelve months should be considered candidates for myringotomy with tube (grommet) placement, according to the American Academy of Pediatrics guidelines.
• Recurrent infections requiring antibiotics is clinical evidence of Eustachian tube dysfunction, and placement of the tympanostomy tube allows ventilation of the middle ear space and maintenance of normal hearing.
• Furthermore, should the patient acquire otitis media while a functioning tube is in place, they can be treated with topical antibiotic drops rather than systemic antibiotics.[rx]

Due to the complex arrangement of structures in and around the middle ear, complications once developed are challenging to treat. Complications can be divided into infratemporal and intracranial complications.[rx][rx][rx][rx]

The following are the infratemporal complications;

• Hearing loss (conductive and sensorineural)
• TM perforation (acute and chronic)
• Chronic suppurative Otitis Media (with or without cholesteatoma)
• Cholesteatoma
• Tympanosclerosis
• Mastoiditis
• Petrositis
• Labyrinthitis
• Facial paralysis
• Cholesterol granuloma
• Infectious eczematoid dermatitis

Additionally, it is important to discuss the effect of OM on hearing, particularly in the 6-24 month age range, as this is an important time for language development, which is related to hearing. The conductive hearing loss resultant from chronic or recurrent OM can adversely effect language development and result in prolonged speech problems requiring speech therapy. This is one reason the American Academy of Pediatrics and the American Academy of Otolaryngology-Head & Neck Surgery recommends aggressive early treatment of recurrent AOM.

The following are the intracranial complications;

• Meningitis
• Subdural empyema
• Brain abscess
• Extradural abscess
• Lateral sinus thrombosis
• Otitic hydrocephalus

Prevention

The following tips may reduce the risk of developing ear infections:

• Prevent common colds and other illnesses – Teach your children to wash their hands frequently and thoroughly and to not share eating and drinking utensils. Teach your children to cough or sneeze into the crook of their arm. If possible, limit the time your child spends in group child care. A child care setting with fewer children may help. Try to keep your child home from child care or school when ill.
• Avoid secondhand smoke – Make sure that no one smokes in your home. Away from home, stay in smoke-free environments.
• Breast-feed your baby – If possible, breast-feed your baby for at least six months. Breast milk contains antibodies that may offer protection from ear infections.
• If you bottle-feed, hold your baby in an upright position – Avoid propping a bottle in your baby’s mouth while he or she is lying down. Don’t put bottles in the crib with your baby.
• Talk to your doctor about vaccinations – Ask your doctor about what vaccinations are appropriate for your child. Seasonal flu shots, pneumococcal and other bacterial vaccines may help prevent ear infections.

References