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Updated 11 February 2013

Dizziness

Dizziness is a sensation which may mean different things to different people. Various meanings may include:Light-headedness, feeling faint.

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Description

Dizziness is a sensation which may mean different things to different people. Various meanings may include:

  1. Light-headedness,
  2. Unsteadiness,
  3. Feeling faint,
  4. Loss of balance, and
  5. A sensation of the environment spinning (vertigo).

Causes and management

There are many possible causes. Problems with the cardiovascular system, the ear organs of balance, or psychological problems can all cause dizziness as a major or minor symptom.

To sort out the basic cause, other symptoms associated with the dizziness are usually investigated, as these will indicate where the problem lies. The table below is a summary of the main types of dizziness and their common causes, which are explained briefly below.

Type of dizziness

Possible cause

Dizziness on standing up

Postural hypotension

Dizziness on looking over the shoulder

Carotid sinus hypersensitivity

Dizziness on exercise

Aortic stenosis/cardiomyopathy

Dizziness on extending and rotating neck

Vertebrobasilar insufficiency

Dizziness and anxiety on hyperventilating

Generalised anxiety disorder

Postural hypotension
This describes a drop in blood pressure on standing up suddenly. Normally, on standing, the blood vessels in the legs constrict a little, so that blood does not pool, by gravity, in the leg veins. If this does not happen, blood remains in the legs, and the amount of blood returning to the heart is dramatically decreased for a few moments: this means that the heart has less to pump out. For a few beats then, less blood gets pumped to the head, and the patient feels light-headed or dizzy. When the leg vessels resume their normal tone, the circulation returns to normal, and the dizziness passes.

This is not a severe problem, passes in moments, and most people adapt by rising slowly. It is common in diabetics and in the elderly, and may happen, for instance, when getting up out of a warm bath, when all the blood vessels are relaxed, and do not respond quickly enough, or after a big meal. It is made worse with alcohol, or anything causing fluid shortage. Avoiding alcohol, not becoming fluid depleted and taking common sense steps to adapt, usually solve the problem. If it persists, the advice of a physician should be obtained.

Tests may need to be done to investigate possible underlying disorders, such as Addison's disease.

Carotid sinus hypersensitivity
The carotid sinus or bulb is found in the carotid artery near where it divides into the external branches to the head and neck, and the internal carotid, supplying the brain. The sinus is sensitive to pressure, and responds by changing the heart rate dramatically. External pressure can trigger a response.

In some positions of turning the neck, structures may press on the sinus, and cause it to change the heart rate, with dizziness as a result.

If this problem is suspected, a cardiologist must be consulted, as the patient may need a permanent pacemaker to prevent a fatal heart rhythm disturbance.

Aortic stenosis/ cardiomyopathy
These are two separate issues.

Aortic stenosis is narrowing of the aortic valve of the heart. This is the main outlet valve between the main pumping chamber and the aorta, which carries oxygenated blood to the whole body. If the valve is narrowed, not enough blood can get out of the heart. If the brain receives too little oxygenated blood, the patient can feel dizzy. Obstruction by the narrowed valve also creates extra work for the heart, as it tries to pump blood through the narrowed opening. Eventually, heart problems may arise, including rhythm disturbances.
With severe narrowing, even a slight rhythm disturbance can result in no blood at all being pumped through the valve for a beat or two: this is enough to make the patient dizzy, or even faint.

The only real treatment for severe aortic stenosis of this sort is urgent valve replacement surgery.

Cardiomyopathy is a disorder of the heart muscle itself, which becomes ineffective. The heart eventually enlarges into a flabby organ, having very little pumping power – in other words, pump failure. The patient feels dizzy because there is simply not enough blood reaching the brain.
Cardiomyopathy may be difficult to control, and is managed by a specialist cardiologist.

Other cardiac problems
If an ECG shows conduction problems in the heart, the patient must be referred to a cardiologist. Patients with pacemakers may need to have them adjusted or replaced.

Vertobro-basilar insufficiency
In this condition, extending the neck – for example, when looking upwards – compresses the vertebro-basilar arteries which supply the brain. A transient ischeamic attack (TIA) can occur: this is a condition which is exactly like a stroke, except that the symptoms clear completely within 24 hours, leaving no neural damage. This type of dizziness has other symptoms, like temporary paralysis, so it usually easy to diagnose.

Any TIA is a warning of a stroke to come, so these patients must be referred to a neurologist or neurosurgeon for full investigation and management.

Ear problems
Some conditions of the ear can cause dizziness, and these usually have other symptoms as well. Viral infections of the balance organ and Meniere’s disease are two common problems. The presence of tinnitus (ringing in the ears) may be a clue here.

Generalised anxiety disorder
This is diagnosed when other organic causes (like heart problems) have been definitely excluded, and the patient has additional symptoms suggesting anxiety disorder, for instance fatigue, sleep disturbances, irritability and so on, all present for more than six months. If the patient hyperventilates, the dizziness may be brought on. This disorder requires treatment, which is usually done by a psychiatrist/psychologist team.

Severe anaemia
This can also cause dizziness, because the blood simply cannot carry enough oxygen to the tissues. Severe anaemia usually has other symptoms, like a fast pulse rate and pallor. Anaemia always has a cause, such as nutritional deficiencies or ongoing blood loss, and this must be identified and treated.

Outcome

With correct diagnosis and treatment, most patients are cured of dizziness.

(Dr AG Hall)

 
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