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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.

Description

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

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.

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


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.

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.

 
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2019-11-18 06:57
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