Definition & Facts
The bony labyrinth consists of sacs and tubes filled with fluid that govern balance and hearing. The cochlea, which looks a bit like a snail shell, makes up about half the labyrinth and transmits sound signals to the brain.
The vestibular organs regulate balance and include the saccule and utricle. Another part of the labyrinth is the semicircular canals. The labyrinth send signals to the brain through the eighth cranial nerve (also known as the vestibulocochlear nerve). Both the labyrinth and the vestibulocochlear nerve can be affected by bacterial infections or viral infections.
Labyrinthitis and vestibular neuritis both cause dizziness and vertigo, but only patients with labyrinthitis develop hearing loss. While the two conditions may produce similar symptoms, they require different treatments, so it is imperative that a doctor make the correct diagnosis.
Symptoms & Complaints
In other cases, the patient experiences feelings of dizziness that both intensify and become more common over a week. Labyrinthitis also causes tinnitus and temporary hearing loss.
Labyrinthitis can also cause fatigue, for it forces the brain to spend an unusual amount of energy on maintaining balance. The patient will also have difficulty sleeping and experience unusually vivid dreams.
In some severe cases, the labyrinthitis will be accompanied by confusion, difficulty walking, double vision (diplopia), or numbness in part of the body (paresthesia). Patients experiencing such symptoms need to call their doctor immediately.
Labyrinthitis generally runs its course between three and eight weeks and then goes away on its own.
Labyrinthitis is most commonly caused by the common cold or flu viruses (influenza virus) reaching the labyrinth and causes inflammation. Infectious mononucleosis (also known as glandular fever), measles, and mumps are also viral infections that can cause labyrinthitis, but they are much less common.
Bacterial infections may also cause labyrinthitis, but they aren’t as common as viral infections. Labyrinthitis can also be caused by a middle-ear infection (otitis media). Traumatic head injuries that damage the ear can also cause labyrinthitis. Allergies like hay fever that affect the upper respiratory tract can cause labyrinthitis. Such allergies inflame tissues of the respiratory system. Autoimmune labyrinthitis is another type of labyrinthitis caused by dysfunction of the immune system.
Labyrinthitis can also be caused by a benign tumor in the middle ear. Extremely high doses of certain medications can also cause labyrinthitis. Examples include aspirin, furosemide, and some antibiotics. An overdose of the anticonvulsant, phenytoin can also cause labyrinthitis.
Diagnosis & Tests
The doctor will start by taking the patient’s medical history and giving them a physical examination. During the medical history, they will ask how long the patient has had their symptoms and how severe those symptoms are. They will look into the patient’s ears and perform some basic neurological tests. For example, they will ask the patient to walk so they can evaluate their balance.
If the patient’s symptoms haven’t improved after six weeks of treatment, the doctor will refer the patient to a specialist. They will recommend tests, often starting with an MRI (magnetic resonance imaging). This test allows the doctor to use magnetic and radio waves to take pictures of the patient’s brain and neighboring tissues like blood vessels.
The specialist will also perform vestibular testing in order to evaluate the function of the inner ear. It generally involves several different tests. The specialist will frequently start with a hearing test to both distinguish labyrinthitis from similar conditions that don’t cause hearing loss and to evaluate its severity. The doctor will also use the results of the hearing test to decide if the patient needs more tests.
Treatment & Therapy
The treatment for labyrinthitis depends on its cause and severity. Antibiotics, for example, can be used to treat labyrinthitis that is caused by a bacterial infection, but they are useless against viral infections.
In severe cases, the doctor may prescribe a benzodiazepine medication. It can quiet the central nervous system and thus prevent abnormal or misleading signals coming from the vestibular system from reaching the brain. These medications can only be used for a short time. The doctor may prescribe other medications to treat vertigo, nausea, or vomiting.
During an attack of vertigo or dizziness, the patient should lie down to avoid injury. These particular symptoms can be exacerbated by bright lights, loud noise, smoking, alcohol, coffee and chocolate. The patient should therefore avoid these triggers as much as possible.
If the patient still has symptoms after eight weeks, they may have suffered some permanent damage to the labyrinth. In that case, they may need to undergo vestibular rehabilitation therapy or VRT, in which they work with a physical therapist. Under the physical therapist’s guidance, the patient will perform special exercises designed to help the patient with dizziness and balance problems.
Prevention & Prophylaxis
Injuries to the head and/or ear can cause labyrinthitis, so a person engaged in activities that risk such injuries should wear protective headgear.
Cold and flu viruses can cause labyrinthitis, so a person with a cold or flu needs to get rest and otherwise take care of themselves to promote healing and keep the virus from spreading to their inner ear. Getting annual flu vaccines is another preventative approach. People with allergies that affect the upper respiratory system need to avoid allergens as much as possible.