What is the Middle Ear?
The middle ear is a middle air-filled chamber that lies between the external ear and the middle ear. The middle ear is connected only to the nasopharynx (posterior part of the nasal cavity) by a tube called the eustachian tube. The eustachian tube should be always patent to equalize the air pressure in the middle ear as the atmosphere.
The middle ear has almost one major function which is the transmission and amplification of the sound waves from the external ear to the inner ear where they will be converted into electrical impulses to be interpreted by the brain. By a simple mechanical mechanism, the intensity of the sound waves reached to the tympanic membrane will be multiplied by 22 in the middle ear to reach the inner ear as more distinct and clear waves.
Middle Ear Infection (Otitis Media)
Otitis media which refers to middle ear infection is an inflammation of the epithelium lining the middle ear which is usually caused by infection. The middle ear isn’t easily accessible by pathogens; therefore, its infection shouldn’t be neglected. Otitis media has different routes of infection, however eustachian tube is the most common route followed by a perforated eardrum.
Otitis media is a common disease in pediatric medicine, so mothers are always advised to notice alarming signs of middle ear infection. The incidence rate of otitis media complications is quite low, yet most of these complications are serious and life-threatening.
Otitis media is classified according to its onset into acute and chronic otitis media. Otitis media could be accompanied by accumulation of mucous, pus, or even serous fluid due to overproduction or obstruction of the drainage through the eustachian tube. Inflammatory stages of otitis media could be observed by inspection of the eardrum, for instance, congested red eardrum means active inflammation.
Otitis media is usually presented by the patients as irritability, pain, fever, and impaired hearing. However, in the case of secretory otitis media, the middle ear is filled with non-infected fluid resulting in absence of otitis media manifestations.
Causes & Risk Factors
Otitis media could be caused by different organisms whether bacteria such as streptococci, Haemophilus influenza, Moraxella catarrhalis, and staph aureus, or viruses such as respiratory syncytial viruses, rhinovirus, and adenovirus. A middle ear infection is usually secondary to an underlying infection such as cold, flu, sinusitis, or rhinitis.
The infection could spread through the eustachian tube and reach the middle ear. Moreover, infection of the upper respiratory tract may result in congestion of the mucosa lining the Eustachian tube and subsequently its obstruction. Several risk factors may predispose people to catch middle ear infection such as:
Children aging between six months to 3 years are found to be more vulnerable to developing otitis media. Children at this age haven’t developed enough immunity to resist simple infections. Furthermore, their eustachian tube is shorter and less sloping which eases its obstruction and spread of the infection from their upper respiratory tract to the middle ear. Pediatricians believe that three out of every three children aging 3 years have had acute otitis media at some point in their lives.