Vertigo

What is vertigo?

Vertigo is an abnormal sensation that causes you to feel as though you are spinning or moving in relation to your environment, or as though your environment is spinning around you, usually with some loss of balance.

Vertigo: causes and risk factors

Vertigo occurs when there is a problem with one of the parts of the body involved in maintaining balance, such as the semicircular canals of the inner ear or the 8th cranial nerve.

The fluid-filled semicircular canals, or vestibular labyrinth, provide the brain with information about movement and how the body is positioned in relation to gravity. The 8th cranial nerve transmits information about balance (and sound) from the inner ear to the brain.

Vertigo is associated with several different disorders. These include:

• Benign positional vertigo: vertigo is triggered by certain head positions e.g. lying on one side or tipping the head back. Possible causes of positional vertigo include middle ear infection, and crystalline deposits in the semicircular canals.
• Meniere's disease: the endolymphatic sac – compartment of the inner ear – becomes distended, probably because of increased pressure. This typically results in vertigo and hearing problems. The exact cause of Meniere's disease is unknown. It may be related to middle ear infection, syphilis or head injury. Other risk factors include recent viral illness, respiratory infection, stress, fatigue, certain medications (including aspirin), and a history of allergies, smoking and drinking alcohol.
• Labyrinthitis: the semicircular canals become inflamed and their function impaired. The cause of labyrinthitis is unknown but it commonly follows middle ear infections or upper respiratory tract infections in children, and is therefore thought to result from viral or bacterial infection. It may also follow allergy, cholesteatoma (a type of cyst in the middle ear), meningitis or ingestion of toxic drugs. Other risk factors include certain medications (especially aspirin), stress, fatigue, and a history of allergies, smoking and drinking alcohol.
• Vestibular neuronitis: inflammation of the 8th cranial nerve.
• Herpes zoster oticus: the 8th cranial nerve is invaded by the chicken pox virus.
• Changes in pressure and gas volume in the middle ear, for example as caused by underwater diving, can in turn detrimentally affect inner ear fluid pressure.
• A burst eardrum may result in associated injury to the inner ear.
• Tumours of the middle or inner ear.
• Tumours of the central nervous system e.g. of the 8th cranial nerve.
• Alcohol, opiates (e.g. morphine, heroin) and certain medications such as the antibiotic streptomycin.
• Diplopia (double vision).
• Motion sickness: disturbance of the sense of balance and equilibrium by certain kinds of motion, which may result in nausea, dizziness and sometimes vertigo.
• Transient vertebrobasilar ischaemic attacks due to a lack of blood supply to the lower areas of the brain.
• Multiple sclerosis: a central nervous system disease involving degradation of the insulating sheath around the nerves.
• Encephalitis: brain inflammation.
• Skull fracture.
• Psychological factors.

Symptoms and signs

Vertigo is a sensation that you or your environment is spinning or moving around. The severity and duration of the vertigo depend on its underlying cause. For example:

• Benign positional vertigo: episodes of vertigo last less than 30 seconds.
• Meniere's disease: episodes may last from a few minutes to over eight hours and tend to worsen with sudden movement.
• Labyrinthitis: vertigo may continue for up to a week at a time, and severe episodes may be followed by transient episodes for several weeks.

Vertigo often occurs together with other symptoms, which vary depending on the causative disorder. Associated symptoms may include:

• Dizziness (feeling faint and as if you might fall)
• Nystagmus (involuntary eye movements)
• Loss of balance
• Hearing loss in one ear
• Noises or ringing in one ear (tinnitus)
• Nausea and vomiting

How is vertigo diagnosed?

Your doctor will take a medical history and ask you to describe your vertigo and any other symptoms you may be experiencing.

An ear examination is vital, as the cause for the vertigo is frequently situated here.

The following tests and examinations may be performed to diagnose the underlying cause of vertigo:

• CT (CAT) scan of the head.
• An MRI (magnetic resonance imaging) scan of head.
• Caloric stimulation (tests eye reflexes). Abnormal results indicate a problem with the inner ear or the balance nerve.
• Electronystagmography, to test for involuntary eye movements.
• EEG (electroencephalogram), evoked auditory potential studies (to measure eletrically the brain’s response to sound stimulation of the ear).
• Neurologic examination to discover abnormalities of the 8th cranial nerve.
• Audiometry (hearing test).

How is vertigo treated?

Often, no treatment is required for benign positional vertigo or cases of mild vertigo. With more serious cases, treatment depends on the underlying cause. Occasionally, medications such as antihistamines, anticholinergics and sedative-hypnotics may be prescribed to reduce symptoms of vertigo.

With benign positional vertigo, you should avoid head positions that trigger episodes. There are special positional maneuvers which can be performed by a specialist which can, however, usually cure this condition, even if only temporarily.

There is no known cure for Meniere's disease. Treatment is aimed at relieving symptoms by lowering pressure within the endolymphatic sac. Antihistamines, anticholinergics, sedative-hypnotics, anti-emetics (antinausea medications), diazepam (Valium), and other medications may relieve symptoms of vertigo, dizziness and nausea. Diuretics (to increase fluid loss) may be used to lower endolymphatic pressure, and a low-salt diet may help reduce fluid retention. Surgery on the inner ear may be required if severe symptoms are unresponsive to other treatments.

Labyrinthitis usually runs its course over a few weeks. Antihistamines, anticholinergics, sedative-hypnotics, anti-emetics and diazepam may reduce symptoms.

With certain disorders, such as Meniere's disease and labyrinthitis, you may need help with walking during attacks of vertigo. Rest during severe episodes, avoid sudden movements and position changes and resume normal activities gradually. Avoid hazardous activities (such as driving or operating heavy machinery) until one week after symptoms disappear. During episodes, avoid bright lights, watching TV and reading, as these may worsen symptoms.

What is the outcome of vertigo?

The outcome of vertigo depends on the causative disorder.

For example, benign positional vertigo can be uncomfortable, but it is not medically dangerous. It usually subsides after a few weeks or months (although it may recur), and it can often be cured by performing certain therapeutic maneuvers.

The outcome of Meniere's disease varies: recovery may be spontaneous, but the disorder may be chronic and disabling. Complications may include being unable to walk or function when vertigo is uncontrollable, and hearing loss on the affected side.

In the case of labyrinthitis, recovery is usually spontaneous. Permanent hearing loss in the affected ear and spread of the inflammation to other parts of the ear or to the brain are rare complications.

Persistent vertigo can interfere with your normal lifestyle. Episodes of vertigo sometimes lead to falls and consequent injuries.

When to call the doctor

Consult your doctor if:

• You experience symptoms of vertigo for the first time.
• Vertigo or an associated disorder has been diagnosed and symptoms worsen or new symptoms develop. Call your doctor immediately if you experience vomiting, fever, convulsions or fainting.

Can vertigo be prevented?

Avoiding head positions that trigger positional vertigo can help prevent episodes.

Prompt treatment of ear infections may help prevent certain disorders associated with vertigo. Prompt treatment of respiratory infections may also help prevent labyrinthitis.

(Reviewed by Dr D. Wagenfeld)