Introduction:
The ear is one of the essential parts of the body. It helps a person in hearing and balancing. Like any other organ, the ear is also susceptible to various disorders and infections. One condition among the many that could affect the ear is vestibular neuritis. Though there is no clear data about this condition’s cause and nature, it is believed that vestibular neuritis or vestibular neuronitis is a condition in which the vestibular portion of eighth cranial nerves gets inflamed. This condition is very commonly interlinked with a preceding viral infection and is said to last several days and sometimes a few months.
What Is Vestibular Neuritis?
Vestibular neuritis is a benign condition that affects the vestibular portion of the eighth cranial nerve of the ear (the eighth cranial nerve is divided into two portions - vestibular and cochlear). It is a sensory nerve that helps in sending information on the head position and balance to the brain. As a result of inflammation, the nerve gets swollen, leading to functional disturbances that cause misinterpretation or lack of interpretation by the brain of the information the ear gives. This condition has no recurrence and can affect anyone, but it rarely occurs in children. It is also a self-limiting condition that usually lasts for several days. But in some cases, the symptoms of vestibular neuritis may take one to two months to resolve.
What Causes Vestibular Neuritis?
Studies have found that the cause of vestibular neuritis is a viral infection affecting the inner ear or infections occurring in other parts of the body. Some of the viral infections that could be responsible for vestibular neuritis include:
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Chicken Pox - It is an infection caused by the Varicella-zoster virus. It is a contagious virus (especially for an individual who did not have this disease earlier) that can spread through sneezing and coughing. In vestibular neuritis, this infection will show symptoms like painful rashes and blisters on the body.
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Hepatitis - It is the inflammation of the liver. There are several types of hepatitis, such as hepatitis A, B, C, D, and E. Viral hepatitis, such as A and E, spreads through contaminated water, seafood, and undercooked pork. Hepatitis B and hepatitis D can spread by coming in contact with an already infected individual’s blood or by contacting body fluids (unprotected sex). It may cause symptoms like dark-colored urine, nausea, and loss of appetite.
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Measles - A contagious and common infection caused by a virus mostly found in the nose and throat. It is commonly seen in children. It spreads through air droplets from infected people when they sneeze or cough. Patients infected with measles in vestibular neuritis have a fever, cold, and cough. Around 90 % of the cases who never had measles or had taken the vaccine are prone to getting it if they come in contact with someone with the measles virus.
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Mumps - An infection caused by the mumps virus (Paramyxovirus) can spread from person to person. It generally affects children from two to twelve years of age; in some cases, it can also affect adults. In adults, it occurs when the immunity level of the mumps vaccine starts to wear off after years. It can easily spread through objects containing infected saliva, such as toys and utensils.
What Are the Symptoms of Vestibular Neuritis?
The symptoms of this condition include:
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Severe vertigo (spinning sensation).
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Nausea and vomiting.
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Blurry vision.
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Difficulty concentrating.
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Difficulty in balance (unable to control body’s position and falling sensation).
What Is the Differential Diagnosis of Vestibular Neuritis?
In patients showing symptoms of vertigo, the differential diagnosis can fall under two etiologies:
1. Peripheral:
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Meniere Disease - The symptoms of this condition last for hours, and the patient might have recurrent episodes of vertigo. In contrast, in vestibular neuritis, vertigo episodes do not repeat for more than one or two days.
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Benign Paroxysmal Positional Vertigo (BPPV) - It leads to brief episodes of mild to moderate dizziness and head spinning. Symptoms usually last for a few minutes. In vestibular neuritis, the head movements are not triggered as much as in BPPV.
2. Central:
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Cerebellar Hemorrhage - It is usually linked with neurological deficits along with recurrent headaches, abnormal pupillary response, and other neurological disorders. Unlike cerebellar hemorrhage, the intensity and onset of vertigo in vestibular neuritis are not that severe.
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Vestibular Migraine - It may show symptoms similar to peripheral and central causes, such as dizziness, nausea, and loss of balance. The patient will have recurrent headaches that may last for hours or sometimes days. The symptoms are more aggravated compared to vestibular neuritis.
How Is Vestibular Neuritis Diagnosed?
In most cases, vestibular neuritis is diagnosed clinically by an otologist (a specialist in the ear). To further confirm the diagnosis, an audiologist (balance and hearing clinician) may perform some simple tests, such as a hearing test and balance test, to check the severity of the condition. If the problem keeps going on for some weeks, then the doctor may advise a few other tests to rule out certain conditions, which include:
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Head Impulse Test - This test is done to check the vestibulo-ocular reflex (VOR), which helps detect how hard or easy it is for the patient to focus on a particular target during head movement. First, the examiner will sit in front of the patient and ask to stare at his nose. Next, the examiner holds the patient’s head and rotates it vertically and suddenly to the right side of the vestibular end. The uncontrollable eye movement depicts vestibular neuritis.
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Magnetic Resonance Imaging (MRI) - The doctor may advise an MRI to rule out other conditions, such as tumors or head injury. A healthcare professional will instruct the patient to lie down on the table attached to the machine. Once the patient is settled, the expert will operate the machine in a different chamber. The machine will take several scans, which take around half an hour to complete. To do a brain MRI, a contrast dye agent is injected in the arm’s vein, which helps in clearer and contrasting images. The sound of the machine will be very loud and high-pitched. The expert will be able to communicate with the patient with an intercom connected to the chambers.
How Is Vestibular Neuritis Managed?
This condition mainly requires supportive care. As it is mainly caused due to viral infections, the doctor will give a treatment plan according to the viral infection that has led to vestibular neuritis. The treatment also involves managing the symptoms that have occurred due to this condition.
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To reduce nausea, medication such as Ondansetron is given. If the vomiting gets severe, the patient is given IV (intravenous) fluids to restore hydration in the body.
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Antiviral medication, such as Acyclovir, helps in treating certain viruses.
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After the initial symptoms are controlled, balance rehabilitation therapy programs are given by professionals who help retrain the brain to adapt to the changes in balance.
What Is the Pathophysiology of Vestibular Neuritis?
Vestibular neuritis is an inflammatory condition that is mainly caused due to a viral infection. Various other theories have also been put forth other than this pathophysiology but are yet to be accepted. Vestibular neuritis and labyrinthitis are very similar disorders, but the primary differentiation is that labyrinthitis leads to swelling of both the vestibulocochlear nerves (vestibular and cochlear portion), but vestibular neuritis only involves the vestibular portion.
Conclusion:
Vestibular neuritis is a condition affecting the inner ear's nerves. This condition occurs only once in most cases (that is in around 95 %) and recurs rarely. It is a self-limiting condition, and the symptoms last two to three days. The doctor will advise balance therapy and medications to treat the virus, which will help regain vestibular function faster. It can be treated easily without complications, and the overall prognosis for this condition is pretty good, supposing proper treatment and balance therapy are sought.
