Otitis Media or Infection of Middle Ear: Stages, Etiology, Symptoms, Treatment
Otitis media typically is inflammation or infection of middle ear. This occurs in area lying between tympanic membrane and inner ear, which includes a duct called Eustachian tube. Its name is derived from the Latin word where "otitis" means inflammation of ear and "media" means middle. This inflammation often begins with respiratory infections that cause sore throats, colds etc. and this then spreads to middle ear. Infections can be caused by viruses or bacteria, and can be acute or chronic. Otitis media typically is one of two frequent cause of ear pain. The other reason is otitis externa. Other diseases/conditions may also result in ear pain e.g. cancer of any structure which shares nerve supply with ears as well as shingles resulting in a condition called herpes zoster oticus etc. Even though it is quite painful, it is self limiting and generally heals by itself within a few weeks. Young children are more commonly affected by otitis media. Symptoms like fever, pain in ears, and sense of fullness of ears, along with irritability, crying and difficulty feeding are present in children. Pressure due to pus or fluid build up in middle ear causes pain and sometimes temporary hearing loss. Contamination as a result of being exposed to cold from other people or children raises risk of getting otitis media. Common cold or some other form of respiratory infections can also lead to otitis media. Bottle feeding also increases chances of infection in ears or inflammation in infants. The line of treatment in otitis media generally is observation, antibiotics, or ear tubes.
Classification and Types of Otitis Media or Infection of Middle Ear
Otitis media of acute type is mostly viral in nature and self limited. It is of quick onset but is of short duration. If it is accompanied by viral URI, then symptoms of congestion of ears and mild discomfort is present which are resolved along with underlying URI. AOM is usually associated with accumulation of fluid in middle ear with signs of ear infections. A bulged eardrum usually presents itself with pain. A perforated/ruptured eardrum often presents itself by draining purulent stuff. This condition is named suppurative OM. There may also be fever along with it. Bacterial cases may lead to perforation of eardrum, infection of the mastoid space (mastoiditis) and sometimes may rarely spread further to cause bacterial meningitis.
3 Stages of Otitis Media or Infection of Middle Ear
- 1st Stage: Exudative inflammation is present which lasts for a couple of days associated with fever, chills, occasional neck stiffness in children, acute pain which is excruciating at night, and muffled sound in ear, deafness, and tinnitus.
- 2nd Stage: Resistance which lasts for a week. Pus in middle ear discharges spontaneously leading to decrease in pain as well as fever. Topical therapy can decrease the duration of this phase.
- 3rd Stage: This is the healing phase which lasts for about a month. Discharge from ear dries and hearing comes back to normal.
Chronic Otitis Media generally is inflammation of middle ear. It involves a perforation (hole) in tympanic membrane and has active bacterial infection within middle ear space lasting generally a month or even more. After an attack of acute ear infection, fluid may stay behind tympanic membrane as long as four months before it resolves. If it remains unresolved, then there is development of chronic OM after some time due to fluid behind tympanic membrane. This condition can result in damage to middle ear as well as eardrum along with continuous pus drainage through perforation in eardrum. This is called otorrhea. This condition generally begins without symptoms. Ear pressure tends to be present for a few months. Sometimes, hearing loss can develop as a result of it.
Serous Otitis Media typically is OM and effusion (OME), also can be termed serous otitis media (SOM). This is a collection of fluid within middle ear space as a result of negative pressure produced by Eustachian tube dysfunction. It usually occurs from viral URI. It is characterized by absence of pain and bacterial infection. It can sometimes present before or after acute bacterial otitis media. Serous Otitis Media sometimes leads to hearing problems. Over a prolonged period of time, middle ear fluid becomes very thick thus increasing likelihood of it causing hearing problems. The causative factors for Serous Otitis Media generally is feeding the infant supine, entering young babies into group child care when their immunity is very low thus making them more prone to infections, secondhand smoking, absence of breastfeeding or a very short time at breastfeeding. All these factors lead to increased duration and occurrence of OME in the first two years of a child's life.
Adhesive Otitis Media generally is characterized by adhesions that are formed as a result of previous middle ear inflammation. Researchers believe that it is a complication of an inadequately treated otitis media of acute type. This condition is developed from the combination of inflammatory exudates and connective tissue proliferation from the inflamed mucosa. The mobility of ossicles and the membrane is diminished and stiffness and rigidity of ossicles may also occur.
Tuberculous Otitis Media is an infectious disease which is very common in developing countries. It starts with painless otorrhoea or discharge from the ear and fails to respond to the usual antimicrobial treatment. The onset of the disease is slow. The discharge is thin, scanty and colorless. The clinical picture is presented with multiple perforations of tympanic membrane and presence of pale granulations. Hearing loss is disproportionate to the symptoms. The painless nature of the infection and low diagnostic suspicion by doctors delays the diagnosis resulting in severe complications like deafness, ataxia, cranial nerve palsy, and intracranial abscesses. Confirmation is done by stained smear, culture of the discharge and biopsy of the granulations. Individuals generally have tubercle infections somewhere else and after it there are multiple tympanic membrane perforations with abundance of granulation tissues as well as bone necrosis and preauricular lymphadenopathy.
Antitubercular drugs should be started immediately to prevent any possible complications. There are instances when combination chemotherapy is done. Surgery is needed in advanced cases to excise sequestra which is a piece of dead bone separated as a result of necrosis as well as for improvement of drainage. The etiology for tuberculous OM is contamination from coughed out sputum from patient with TB, drinking unpasteurized milk of infected cows, and may also be blood borne.
Pathophysiology of Otitis Media or Infection of Middle Ear
Eustachian tube has mucociliary action and ventilatory function which clears the nasopharyngeal flora entering middle ear. However, when upper respiratory viruses infect middle ear, this can impair its mucociliary action and ventilatory function process, which then contributes to the development of Otitis Media of the acute type. Viral infection causes inflammation of nasal passages and Eustachian tube, which leads to impairment of the normal mucociliary clearance and ventilation of middle ear and this leads to middle ear effusion. Moreover nasopharyngeal bacteria contaminate the effusion. This middle ear effusion provides a good medium for bacterial growth, which in turn triggers a suppurative and inflammatory response. This formation and discharge of pus creates pressure against tympanic membrane leading to pain and fever, which are the typical symptoms of AOM. In more severe cases, tympanic membrane may perforate/rupture causing a purulent discharge from the ear known as otorrhoea. Mastoid air cells may also be involved in the inflammatory process. Though it is painful, it is not life threatening, is self limited and generally heals by itself within a few weeks.
Etiology and Risk Factors of Otitis Media or Infection of Middle Ear
Otitis media generally is as a result of bacterial, fungal, or viral infections, of which Streptococcus pneumoniae is very common. There are others including Pseudomonas aeruginosa and Moraxella catarrhalis. In young adults, common reason for ear infection can be Haemophilus influenzae. RSV and viruses causing common colds can also cause otitis media as they damage epithelial cells of upper respiratory system.
One of the major risk factors in development of otitis media known is Eustachian tube dysfunction. This results in inadequate clearance of bacteria from middle ear and results in otitis media.
Young children are at greater risk of developing otitis media due to having shorter and more horizontal Eustachian tubes when compared to adults, decreased immunity to viruses and bacteria than adults, less duration of breastfeeding, bottle feeding in supine position, smoking habit in parents, diet, allergy, and automobile emissions/polluted air with irritants etc. Children with cleft palate or Down's syndrome are more inclined to have ear infections. Problems with the Eustachian tubes like blockage, malformation, inflammation also increases the risk of otitis media. Children who have suffered from episodes of otitis media of acute type before six months of age are more prone to ear infections later in their childhood.
Signs and Symptoms of Otitis Media or Infection of Middle Ear
- Runny or stuffy nose.
- Temporary hearing loss
- Young children may be irritable, fussy, or have problems feeding or sleeping.
- Older children may complain of pain and fullness in ears.
- Severe infection may cause rupture of eardrum.
- Discharge (otorrhoea).
Treatment for Otitis Media or Infection of Middle Ear
- Symptomatic treatment can be done using oral and topical analgesics to treat pain. Oral medicines used are ibuprofen, acetaminophen, as well as narcotics. Topical medications are antipyrine eardrops. Nasal or oral decongestants or antihistamines are not recommended due to their lack of benefit and potential side effects.
- Antibiotics can be delayed by one to three days if pain is manageable as two out of three children with otitis media of acute type resolve on their own without any treatment. The recommended antibiotic, if required, is generally amoxicillin. If there is resistance to this medication, then another penicillin derivative along with beta lactamase inhibitor can be used. Long-acting azithromycin has been found to be of better effect than short acting medications.
- Tympanostomy tube is used in chronic cases with effusions. The tube is inserted into eardrum and reduces the recurrence rate of otitis media in the 6 months after its placement, but has negligible effect on long term hearing. For this reason tubes are recommended in those patients who have more than 3 episodes of otitis media of acute type in 6 months or 4 episodes in a year accompanied with effusion.
Investigations for Otitis Media or Infection of Middle Ear
- There are no definitive lab investigations for otitis media of acute type. Diagnosis is done on the basis of acute onset, middle ear effusion (MEE), and middle ear inflammation. Other than this Pneumatic otoscopy helps in assessing the mobility of tympanic membrane. It helps in differentiating otitis media from otitis media of acute type. A normal tympanic membrane moves easily to pressure changes whereas if effusion is present, the movement is slow or may even be immobile.
- Tympanometry tests the ability of the eardrum to react to sound and conduction bones by creating differences in air pressure in ear canal.
- Myringotomy is a procedure which is performed under local or general anaesthesia in which a small incision is made into tympanic membrane to confirm presence of middle ear effusion and then relieve pressure caused due to accumulation of fluid.
- Appearance of tympanic membrane is highly suggestive in diagnosing and differentiating otitis media from otitis media of acute type.