Labyrinthitis

The inner ear has two main functions. It detects position and motion, maintains balance, and enables hearing by converting the mechanical signals into electrical signals.

It is located within the petrous part of the temporal bone in the inner ear. It also lies between the middle ear and the internal meatus. There are two main components of the inner ear, and these are the bony labyrinth and membranous labyrinth.

A series of bony cavities is referred to as bony labyrinth. It consists of structures, such as vestibule, cochlea, and three semi circular canals. Internally, these structures are lined by periosteum and within them a fluid known as perilymph. Within the bony labyrinth, there is a structure known as membranous labyrinth. It is composed of cochlear duct, saccule, utricle, semi circular ducts. A fluid known as endolymph fills the membranous labyrinth.

The middle ear opens into the inner ear by two openings that are covered by a membrane. Between the middle ear and the vestibule lies the oval window, and the middle ear is separated from the scala tympani by a round window.

• Bony labyrinth: Within the petrous part of the temporal bone are present series of bony cavities known as bony labyrinth. This component consists of three main parts that is the cochlea, three semicircular canals and vestibule.
• Vestibule: This is the central part and it is separated by an oval window in the middle ear. Anteriorly it communicates with the cochlea and posteriorly it communicates with semicircular canals.
• Cochlea: The cochlea duct is present in the cochlea. There are two peri lymph filled chambers created by this cochlear duct. These are scalavestubuli and scala tympani.
• Semi circular canals: Anterior, lateral and posterior are three semicircular canals that consist of the semicircular ducts. At one end of the canal, there is a swelling known as ampulla.
• Membranous labyrinth: This is filled with endolymph and it is composed of continuous system of ducts. Within the bony labyrinth, lies the membranous labyrinth. It consists of cochlear duct, three semi circular duct, utricle and saccule.

• Cochlear duct: This structure is located within the bone scaffolding of the cochlea. The spiral lamina holds the cochlear duct in place. It has a triangular shape composed of a lateral wall, a roof and floor.
• Saccule and utricle: In the vestibule, these two membranous sacs are located. Movement of the head is detected by these organs of balance; they can detect the acceleration of the head when moving on a vertical or horizontal plane. Utricle is a larger structure that receives those semicircular ducts. The cochlear duct receives the saccule and has a globular shape. This drains into the endolymphatic duct from the saccule and the utricle endolymph drains out
• Semicircular duct: The semicircular duct is located within the semicircular canals. When the head moves, it causes changes in the speed and direction of the flow of the endolymph. These changes are detected by the sensory receptors present in the ampullae, after which to the brain, signal is sent with the help of which balance is processed.

An inner ear viral infection is described as labyrinthitis. Dizziness and vertigo are some of the common symptoms that a person with labyrinthitis may experience. When the labyrinth is exposed to a viral illness, then it may get inflamed, which may result in labyrinthitis. Severe discomfort and lethargy may occur when the labyrinth is damaged, since it is the deep structure within the ear with the cochlea and the vestibular system, which is responsible for hearing and maintaining balance respectively. A person with labyrinthitis may struggle with daily tasks.

When the labyrinth is inflamed it causes labyrinthitis. The labyrinth controls balance and hearing. This structure is made of channels filled with fluid, which moves when the head moves, and from this the brain is able to determine in which the direction the person is moving, how fast and how far the person is moving. The body is balanced from this information. A part of the labyrinth also known as cochlea controls hearing. Inflammation of the organs that control balance can cause different information to be sent to the brain from the unaffected ear, which can make the person feel dizzy. If this part of the inner ear is inflamed, then it may also affect hearing of the person.

Mostly a viral infection causes labyrinthitis. Mostly after viral infections, such as cold or flu, labyrinthitis will happen. One study showed that one in 600 cases of influenza may have acute labyrinthitis. It may cause vertigo that may be sudden and violent; it can further cause nausea, vomiting, and loss of hearing. Symptomatic treatment is needed since antibiotics will not work against viruses. The doctor may prescribe antihistamines, antivertiginous medications and may advice the person to do bed rest.

Usually the person suffering from vertigo is able to sit up within one week and is able to compensate for their conditions after two weeks. It may take 1-2 months for acute episodes to end. If the labyrinthitis is viral mostly people are able to recover from it but if the vestibular is damaged then this condition can be permanent. Vestibular rehabilitation exercises help in cases of residual imbalance. In order to recover, patients are sometimes recommended by the doctor to do vestibular rehabilitation exercises.

If there is a chronic state of an ear infection then either through the bone, round windows or some ear or head injury the bacteria may enter the inner ear. Hearing loss may be sudden and unilateral. Along with this the person may even experience sickness, vertigo and nystagmus. Cases are usually managed successfully by taking antibiotics. For at least one week after the symptoms go away the person should take care when driving, or operating machinery since the symptoms may return.

Vertigo and hearing loss are primary symptoms of labyrinthitis. Also it may cause tinnitus, a sensation of ringing in ears. The inner ear is responsible for maintaining a sense of balance and hearing and when this is affected, then it causes vertigo. In some individuals, in the direction of the unaffected ear, there is spontaneous eye movement, and some may experience nausea and vomiting. A discharge may be produced from the ear that is infected due to bacterial labyrinthitis.

In nearly all cases of labyrinthitis, three common symptoms are observed. These are vertigo, dizziness and loss of hearing. The symptoms may appear in short bursts in mild cases, but if it is severe then the person may not be able to stand upright due to high intensity loss of balance.

Some other symptoms that patients may experience are:

• Some may experience mild loss of hearing and some may experience total loss of hearing
• In the affected ear pressure may be exerted
• Some may feel tinnitus
• Pain in the ear
• Nausea or vomiting
• Vision may get blurred or there may be double vision
• Higher body temperature or may feel feverish

It is advised that one should not use any machinery or use tools when one feels dizzy or unbalanced. Depending on the severity the symptoms will last. In some cases the symptoms can last for a few weeks and in some for months.

There is another condition known as vestibular neuritis, in which there is no hearing loss but there may be loss of balance.

Viral infections, such as cold, flu, sore throat, and glandular fever can cause labyrinthitis.

Labyrinthitis can be triggered by other conditions, such as:

• Injury in the ear
• Any kind of allergies
• A condition known as meningitis
• Bacterial infection in middle ear
• Obstruction of blood circulation to a part of the brain
• Tumors
• Medication side effect                    

In one study, it was noted that one of the complication of Kawasaki disease is labyrinthitis, which is most often underdiagnosed.

The doctor should be called if the child has nausea, vomiting or vertigo. Based on the symptoms and the history, the doctor will diagnose labyrinthitis. The doctor will examine whether the person had any previous upper respiratory infection. The child's hearing will be tested and if the patient has a discharge from the ear then the doctor will order for laboratory culture to identify its cause.

Tests can be ordered, such as a CT scan or MRI, if there have been no recent infections. By doing these tests, the doctor can rule out other possibilities, such as tumors. Blood tests may be ordered if bacterial labyrinthitis is suspected, in some cases, analysis is done from the fluid that drains from the ear so that the type of bacteria can be determined.

The doctor may perform a number of tests in order to reach the diagnosis. To see whether the person experiences dizziness, the doctor may turn the head of the person. In certain cases, an MRI may be needed. Mostly this condition only affects one ear.

A diagnostic algorithm was created in order to determine vertigo in all young dizzy patients by doing a certain number of studies.

It is necessary that one should seek medical attention if the attacks of vertigo are so sudden that it can cause deafness in one ear. This may indicate that a part of the brain is blocked by a blood vessel or there may be a need of hearing aid support due to some additional problems. Anti sickness medication may be prescribed by the local doctor in persistent cases, which are less intense. These medications will help to reduce the inflammation and help the person with vertigo. A person may be referred for vestibular rehabilitation therapy if within a few weeks the symptoms do not clear up.

Specific treatment is prescribed for labyrinthitis in which the causes are less common. For instance, antibiotics are prescribed if there is a bacterial infection in the middle ear.

Some of the symptoms of labyrinthitis can be alleviated by a variety of self help options in those suffering from labyrinthitis. Dizziness can be reduced by taking certain measures, such as bed rest, exposure to bright light should be minimized, and drinking adequate amount of water. Also stressful situations should be avoided.

In most of the cases after some time hearing and balance returns back to normal. In some cases when people move their head they may experience slight dizziness. This can remain many years even after the infection has gone away. Complications due to labyrinthitis are very uncommon, but there can be certain complications such as permanent hearing loss, imbalance or tinnitus. Also the chances of complications are more with bacterial labyrinthitis.