Labyrinthitis

 

What is it?

Labyrinthitis (sometimes known as vestibular neuronitis) is an inflammation of the balance organs of the inner ear, the semi-circular canals. These are three horseshoe-shaped tubes within the skull, just deeper in than the middle ear chamber (containing the ear drum and the bones that transmit sound to the hearing organ of the inner ear, the cochlea). They are set at right angles to each other, and detect movement of the head, sending signals down nerve fibres to the brain to give information about movement.

Labyrinthitis can occur at any age, though it is more common in middle-aged and elderly men and women than in young adults. It is experienced as dizziness (vertigo).

 

Why does it occur?

Labyrinthitis is usually caused by a virus infection, and may sometimes follow a cold, sore throat or ear infection. Other less common causes include the spread of a bacterial middle-ear infection (otitis media), head injury, and severe psychological stress.

Labyrinthitis is one cause of vertigo but vertigo can also be caused by other conditions such as Meniere’s disease (a disorder which results in episodes of vertigo, tinnitus and deafness) and something called Benign Positional Vertigo (BPV) causing vertigo when the head is in certain positions. Rarer causes of vertigo include cholesteatoma (an accumulation of debris covered by skin in the outer ear canal), brain tumours, and syphilis (extremely rare). 

 

How does it occur?

The semicircular canal tubes are filled with fluid. Normally, when the head is moved, the fluid flows over tiny hairs at each end of the tubes, bending them. The hairs are connected to nerve fibres, which are stimulated when the hairs are bent. These nerve signals are sent to the brain, which then fits them in with signals from the eyes and the rest of the body, to form a sense of what position the body is in, and in what direction it is moving.

In labyrinthitis, these tubes are not working properly, and this makes the signals to the brain inaccurate. The resulting confusion, in the part of the brain that gives a sense of balance and position, generates dizziness (vertigo), and nausea. The brain is unable to “tell” the body how to move to keep balanced, and the result is the inability to co-ordinate, with falling over and loss of balance.

 

What are the symptoms?

Subjectively, labyrinthitis feels the same as motion sickness, or the familiar spinning feeling we experience as children after getting off  a merry-go-round, even though the ground is actually still.  It is often coupled with nausea, and if it is severe enough, vomiting.  The slightest head movement can trigger severe dizziness, and there is a tendency for the body to fall towards the affected side.

Involuntary flickering eye movements (nystagmus) can occur and  the sufferer may find it difficult to fix their eyes on a stationary object. The symptoms are usually at their worst for a week or so, then gradually improve. The majority of individuals are completely better by six weeks, though in a few cases, the inner ear remains sensitive for a few months, and dizziness may be triggered easily, for instance by a car journey.

 

What are the complications?

The main complications of labyrinthitis are:

  • Injury through falling over although this tends only to occur in severe cases
  • Dehydration through excessive vomiting although again this is unusual

It is not uncommon for individuals who are recovering from labyrinthitis to become slightly depressed and miserable. The symptoms make one feel bad enough, but often one’s confidence takes a knock and there seems to be some extra effect of the illness which makes depression more likely afterwards.

 

What are the tests?

Bacteriology and microscopy

On the rare occasion that labyrinthitis is associated with a bacterial ear infection, with discharge of pus from the ear canal, then a swab can be taken and sent to a laboratory for analysis. This can show which bacteria are involved and what antibiotics they are sensitive to. This can then guide treatment or confirm that the right antibiotics have been started.

The following tests would only be done if the dizziness of labyrinthitis persists for longer than the six weeks it sometimes takes to settle on its own.

Audiometry

This measures hearing, and can help to show whether there is an additional problem with the cochlea.

Brain-stem auditory evoked responses (BSER)

This measures the brain’s response to sounds, and gives information about the functioning of the nerve connections between the ear and the brain.

Calorimetry

This shows the response of the brain’s control of eye movements to the stimulus of cold water in the ear canal.  It helps to show in which part of the ear systems there may be a problem.

Electroencephalography (EEG)

This measures the tiny electrical signals produced by the brain, detectable through wires (electrodes) on the scalp.  It helps to show if there is a problem within the brain itself.

Magnetic Resonance Imaging (MRI) 

Also sometimes referred to as Nuclear Magnetic Resonance (NMR) scanning.  A detailed three-dimensional image of the brain and the inner ear is produced using powerful magnetic fields.  It is very good at showing nerve damage or growths within the hearing (acoustic) and balance (vestibular) nerves, or the brain.

 

What is the treatment?

Drug treatments may include:

  • Antihistamines, usually used to treat allergic reactions, also have a direct effect on calming the jangled nerve signals of labyrinthitis. They are effective in reducing dizziness and nausea. Well-known ones include cinnarizine, promethazine and cyclizine and dimenydrinate. A similar drug called betahistine (Serc) is also sometimes used for the treatment of labyrinthitis
  • Phenothiazines are another useful group of drugs in treating dizziness and nausea.  The most commonly used is prochlorperazine (Stemetil)
  • Benzodiazepines can be useful if dizziness recurs after the initial illness is over or if it is thought that the labyrinthitis is thought to be related to stress or anxiety
  • Antibiotics are useful only if there is a bacterial infection causing the labyrinthitis

Vestibular Rehabilitation Therapy

..is a type of treatment sometimes used to help people to adapt to the dizziness caused by Labyrinthitis (or some other forms of vertigo).

It involves doing certain exercises for 20 minutes or so two-three times a day. The exercises involve such things as holding the head in a position which normally induces vertigo  or practising  certain eye movements. Occasionally, balancing exercises are done with the patient standing on different surfaces such as foam or cushions with the eyes closed in order for the brain to concentrate on the signals being sent to it from the balance organs.

Vestibular Rehabilitiation Therapy often has to be done regularly two to three times a day for several months before improvement is seen so it is usually only suggested if the dizziness from the labyrinthitis is not showing any signs of improving after a few weeks or months.

Surgery

This is rarely used in the initial illness and only if there is a bacterial infection of the inner ear, and involves opening the inner ear to drain pus. This may also involve mastoidectomy, the opening of the bone of the skull just behind and below the ear. It is a major operation, and is not done without very good reason. It has a number of complications including total hearing loss and facial paralysis on the side of the operation. It should be discussed in detail with the surgeon planning the operation.

 

What are the treatment side effects?

All drug treatment can cause allergic rashes and reactions, though these are rare. A careful assessment of their likelihood and whether the risk is worth taking will be made by the prescribing doctor.

The antihistamines as a group tend to cause sedation. They should not be taken if likely to drive or operate machinery and should not be used if glaucoma or bladder emptying problems (urinary retention) are present. The phenothiazines can make Parkinson’s disease and other movement disorders worse.

Benzodiazepines such as diazepam are sedative, and are addictive if used for long periods of time. They should be used very carefully and only absolutely as necessary.

 

What self-help strategies are there?

There is no sure way to prevent labyrinthitis from happening. If dizziness and sickness follows on from a cold, sore throat or ear infection, seek medical help straightaway, as the distressing symptoms can be controlled. Once the initial illness has settled, it is important not to put too much strain on the inner ear: this means resuming normal activities gradually, avoiding strenuous physical activity until everyday life is back to normal. 

It is not safe to drive a car or operate hazardous machinery until after the symptoms have completely disappeared.

 

What about family and friends?

An individual suffering from severe acute labyrinthitis may need to be looked after until he or she is able to walk safely.  In the severe initial part of the illness, even going to the bathroom can be a hazardous journey.  Later on, encouragement and support are important to ensure a return to normal life, and reduce the risk of depression setting in.  If the sufferer seems to be getting more and more depressed after the initial illness has settled, encourage him or her to see a doctor in case antidepressant treatment is necessary.

 

Where can I get further information?

Apart from contacting your GP, the following organisation may be of further help:

Defeating Deafness (Hearing Research Trust)
330-332 Gray's Inn Road
London
WC1X 8EE
Telephone: 0207 833 1733
TEXT: 0207 915 1412
Email: contact@deafnessresearch.org.uk