The middle ear infection, i.e., Otitis media, is the most common type of ear infection and one of the most frequent infections in the human body. To understand why middle ear infections are so common, we must first look at the anatomy of the middle ear.
Middle Ear Anatomy
The middle ear is shaped like a room or cuboids with six walls with one cubic centimeter volume. The middle ear has bones on five sides, the sixth side being the eardrum or the tympanic membrane. The eardrum comprises three layers: an outer skin lining, a fibrous coat framework in the middle, and an inner mucous membrane.
For the eardrum to vibrate precisely as per the sound, the air pressure in the middle ear must be equal to atmospheric pressure, for which it needs a constant air supply. In other words, for it to vibrate to its total capacity to deliver good hearing, the air pressure on both sides of the eardrum must be equal. When we swallow, air travels from the back of our nose, i.e., the nasopharynx, to the middle ear via the eustachian tube, ensuring that the middle ear has a constant air supply. The middle ear has a reservoir of air in the temporal bone called the mastoid cellular system.
Malleus, incus, and stapes
This middle ear has three bones, malleus, incus, and stapes. These bones are suspended in the air and move freely to transmit the sound signals from the middle ear to the inner ear. The three bones are like a chain connecting the eardrum and inner ear so that they can transmit the vibrations from the eardrum to the inner ear. Malleus is attached to the eardrum. Stapes bone is attached to the inner wall of the middle ear, which continues to the inner ear, forming a mobile union with the inner ear. These bones move like a piston to transmit the vibrations.
Functions of the inner ear and how otitis media can affect its functions
The inner ear has fluid that will vibrate as per the sound waves transmitted from the eardrum through the middle ear bones malleus, incus, and stapes chain. The inner ear has hair cells concerned with each frequency in our hearing range. The particular hair cell concerned with the frequency gets stimulated when we hear the sound. Each hair cell has a micro-generator turbine at the base of the cell, which transports one electron from anion to cation, and this electron travels to the brain through the cochlear nerve. The middle ear infection can also spread to the inner ear, whose job is to hear through the cochlea and balance through the vestibular labyrinth. So when the inner ear is affected, we can experience loss of hearing, giddiness, or loss of balance.
Nerves that can be affected by Otitis media
The facial nerve controls facial expressions, eye closure, and a few muscles around the mouth, and it travels through the middle ear. One more nerve called the chorda tympani nerve connects taste fibers from the front part of the tongue to the brain. The facial nerve and chorda tympani nerve can be affected due to Otitis media.
Otitis media in babies
A middle ear infection is common in babies below six months. Babies below six months have small skulls to accommodate easy birth. Their little heads do not have enough space to align the eustachian tubes at an angle like in adults. The horizontal alignment of the eustachian tube increases the risk of middle ear infection as infected fluids can easily leak into the middle ear.
Babies enjoy the sweet taste of milk and prefer to sleep with it in their mouths.
Milk ferments or spoils faster due to bacteria that dwell in our mouths. The fermented milk can slip into the nasopharynx, from where it can leak into the nose or middle ear. If the spoiled milk slips into the nose, the baby can get rhinitis, i.e., the common cold. If they slip into the middle ear, they will get an ear infection. Please read our article on “What causes ear infections in a baby?” to understand more.
Otitis media in kids (one to six years)
Children can have adenoids, i.e., extra tissue formed due to allergy or viral infections at the back of the nose or nasopharynx. Adenoids are like tonsils tissue, enlarged tissue that causes problems. The nasopharynx is like a cube with 2cms on each side. The presence of adenoids in such a small area can disturb the eustachian tube, often resulting in middle ear infections in kids.
Middle Ear Infections in adults
As discussed earlier, the middle ear connects to the back of the nose, the nasopharynx, via the eustachian tube. Any infection in the back of the nose can affect the middle ear.
The most common infection in both body and nose is rhinitis, a common cold. The infection can spread from the nasopharynx to the middle ear whenever we have a common cold. However, it is prevented as the eustachian tube is slanted. However, when we blow the nose, especially one nostril is blocked, high pressure is created in the nasopharynx pushing the fluids with high bacteria content into the middle ear through the eustachian tube.
Blowing out the nose when we have a common cold can result in a middle ear infection. 90% of middle ear infections are because of the common cold.
If the infection in the middle ear is less than two weeks duration, it is called acute suppurative otitis media. When the disease stays for more than six weeks, it is called chronic suppurative otitis media.
2. Chronic Sinusitis
In chronic sinusitis, the infected secretions of sinusitis are pushed out from the sinuses to the oropharynx or back of the throat. The palate is a soft tissue that divides the oropharynx and nasopharynx. These liquids can seep into the nasopharynx and then into the eustachian tube and consequently into the middle ear. Please read our article “Ear pain or clogged ears with a sinus infection” to understand how chronic sinusitis can cause middle ear infections.
Middle ear infection symptoms
90% of middle ear infections are due to the common cold. The disease generally starts with a common cold, and during the end of the infection or in the second week, the infection will progress to the middle ear. The patient will start experiencing pain and block sensation in the ear. When the middle ear has fluid or pus, the eardrum vibration is affected as it tampers the air pressure in the middle ear. As the infected fluid causes infection and inflammatory chemical mediators are released, which irritates the pain nerve endings. As the fluid increases in the middle ear, the pain worsens. When the fluid increases, the pressure in the middle ear bulges the thin papery eardrum. After a limit, the eardrum bursts out, and thick watery pus comes out. As the eardrum bursts, the severity of the pain comes down. As the infection continues, pus keeps coming out of the ear. There is a chance that the bacteria in the outer ear move into the middle ear through the perforation of the eardrum, increasing the middle ear infection. So, once the perforation happens, hearing loss increases. Most of the time, hearing loss is around 10 to 30% only. As the infection increases, our body increases the blood supply to the ear so that the WBCs can fight the infection. The tiny ear bones can get damaged during this process, and hearing loss can go to 60%, and if the infection spreads to the inner ear, the hearing loss will mostly be 100%. As pus in the ear is less, they might not have a fever. Fever is a rare symptom.
So, we can list the following as middle ear infection symptoms
1. Severe ear pain
3. Ear discharge
4. Deafness or block sensations
Middle ear infection diagnosis
An ENT doctor diagnoses a middle ear infection in the early stages by an impedance audiometry test that measures the pressure in the middle ear. If the test gives a B type of curve, which confirms fluid in the ear. When there is perforation, the impedance audiometry gives high canal volume and a B type of curve.
Treatment for middle ear infection
The primary treatment is controlling the root cause, i.e., common cold or sinusitis. If the infection is viral, then we do not use antibiotics. If the infection in the nose is for more than five days, we assume there is superadded bacterial infection, and we prescribe antibiotics. We should not allow water into the ear as the water can carry the bacteria of the outer ear into the middle ear adding up to the existing infections. An ENT doctor must treat any other coexisting factors like allergy exists. In the acute case, the disease is due to gram-positive bacteria, and the antibiotic is directed toward it.
Middle ear infection home remedies
A middle ear infection is often a secondary infection to a common cold or sinusitis. So if we use home remedies to control these infections, we can either prevent the middle ear infection or help our body fight it.
Common cold or rhinitis
1. Use nose drops when you get the common cold
2. Steam inhalation
3. Saltwater gargling
4. Do not blow the nose as it creates high pressure in the nasopharynx, pushing the infection into the middle ear via the Eustachian tube.
An Article By
Dr. K. R. Meghanadh