Labyrinthitis - Causes, Triggers, Diagnosis, and Treatment

Introduction:

A labyrinth is a fluid-filled sac or tube that is present in the inner ear. Labyrinths are of two types that are bony labyrinths and membranous labyrinths. A bony labyrinth is a group of bony cavities situated in the lateral part of the skull (temporal bone) consisting of the vestibule (central part of the inner ear), cochlea (snail-shaped organ), and semicircular canals (three small fluid-filled tubes). The membranous labyrinth is present within the bony labyrinth. Swelling in the labyrinth is called labyrinthitis. Labyrinthitis can cause loss of hearing and balance.

What Is the Prevalence of Labyrinthitis?

• Labyrinthitis most commonly affects adults in the age group of 30 to 60 years old.

• It is more common in females than males.

What Is the Incidence of Labyrinthitis?

The incidence of labyrinthitis is around 3.5 cases per 100,000 per year.

What Are the Causes of Labyrinthitis?

The swelling of the labyrinth is caused by the following:

• Viral Infections: Viruses like herpes zoster and Epstein Barr virus can cause swelling in the labyrinth and the eighth cranial nerves (vestibulocochlear nerve).

• Bacterial Infections: Bacteria causing middle ear infections (seen mostly in children) can spread to the inner ear and cause swelling of the labyrinth.

• Autoimmune Disorders: Autoimmune (body kills own cells) disorders Like rheumatoid arthritis can cause labyrinthitis (rare cases).

• Trauma: Trauma to the inner ear during the surgery can cause swelling of the labyrinth.

• Cancerous or Non-cancerous Tumor: A tumor involving the nerve supplying to the inner ear (eighth cranial nerve), like acoustic neuroma, can cause inner ear swelling.

What Are the Trigger Factors of Labyrinthitis?

Factors that can cause an increased risk of swelling in the labyrinth are:

• Cold and flu.

• Alcohol.

• Stress.

• Recurrent ear infections.

• Smoking.

• Drugs like Antidepressants or ototoxic drugs (drugs toxic to the ear).

What Are the Signs and Symptoms of Labyrinthitis?

• Loss of balance.

• Partial or complete hearing loss.

• Dizziness.

• Vertigo (spinning sensation in the head).

• Nausea and vomiting.

• Tinnitus (ringing in the ears).

• Disorientation.

• Nystagmus (uncontrolled eye movements).

• Blurred vision.

• Fever.

• Pressure changes in the ear.

• Pain in the ears.

How To Diagnose Labyrinthitis?

Labyrinthitis can be diagnosed by :

• Clinical Examination and History: The history of the patient for precious ear surgeries, any recent trauma to the ear, and the symptoms present are recorded. Clinical examination of the ear is done by an ENT (ear, nose, and throat) surgeon using an otoscope (a device with attached light) to check for any discharge through the ears and the presence of any infections in the ear.

• Audiometry (Hearing Test): The hearing test is done to check the severity of the hearing loss and to detect the presence of sensorineural hearing loss (hearing loss caused by damage to the nerve). In this procedure, the electrodes are placed in the back of the scalp and near the ears, and sounds of different frequencies are produced in the ears with the help of a mini speaker. The response of the brain to the sound produced is recorded in an audio graph which is assessed later. It helps to rule out the defect in the hearing or auditory pathway.

• Videonystagmography (VNG): It is done to rule out the problem in the vestibular system (labyrinth and eight cranial nerves). An electrode is used in this test to check eye movements by using infrared goggles.

• Computed Tomography (CT) Scans: It is done to rule out any cancerous or noncancerous tumor growth involving the vestibulocochlear (eighth cranial nerve) nerve-like acoustic neuroma.

• Electrocardiogram (ECG): It is done to rule out the causes of heart disorders.

• Electroencephalogram (EEG): It is done to detect the electrical activity of the brain as conditions like a brain tumor and stroke present similar symptoms.

What Is the Treatment of Labyrinthitis?

Treatment of labyrinthitis is done based on the symptoms present:

• Antibiotics: Antibiotics are given to patients for bacterial infections.

• Antiviral Medications: These drugs are prescribed to control viral infections.

• Steroid Therapy: Steroids are prescribed by the doctor for a reduction in the swelling of the labyrinth and the auditory (nerve supplying the ear) nerve. Intratympanic (within the tympanic membrane) injections of prednisolone are given to increase the efficacy of the drug at the target site. Steroid injections are given directly in the inner ear by passing the needle through the oval window and depositing the drug in the inner ear, but it is quite a technique-sensitive (risky) procedure.

• Treatment of Vertigo: Episodes of vertigo are controlled by benzodiazepines and antihistamines drugs. These drugs are given for the short term as they can inhibit the recovery of balance function.

• Antiemetics: These drugs are given to the patient for controlling nausea and vomiting.

• Vestibular Rehabilitation: Balance exercises are taught under the supervision of therapists in vestibular rehabilitation centers. It helps to recover from the balance loss.

What Are the Complications Associated With Labyrinthitis?

Complications that can occur if swelling in the labyrinth is left untreated for a longer duration are:

• Permanent hearing loss.

• Loss of vision.

• Loss of balance (due to permanent damage to the auditory nerve).

How To Reduce the Symptoms of Labyrinthitis?

• Avoid sudden changes in posture to reduce vertigo episodes.

• Take adequate rest.

• Drink plenty of water.

• Avoid alcohol and smoking.

• Avoid loud noise and bright lights.

• Take a warm compress near the ears.

• Avoid stress.

• Avoid driving, climbing, and doing heavy exercises for a week after the symptoms subside.

Conclusion:

Labyrinthitis is caused due to swelling of the labyrinth (inner part of the ear) and vestibulocochlear nerve (the eighth cranial nerve) due to bacterial or viral infections. It can result in loss of hearing, balance loss, dizziness, and episodes of vertigo. Early diagnosis and management of labyrinthitis are important to prevent the worsening of the symptoms. Vertigo episodes associated with labyrinthitis usually resolve in a few days or weeks. The presence of vertigo, even after weeks, along with other symptoms like double vision, frequent nausea, and vomiting, should be reported to the doctor immediately as it indicates life-threatening disorders like a brain tumor and stroke as it presents with similar symptoms like labyrinthitis.