Topic Overview

Dizziness is a word that is often used to describe two different feelings. It is important to know exactly what you mean when you say "I feel dizzy," because it can help you and your doctor narrow down the list of possible problems.

• Light-headedness is a feeling that you are about to faint or "pass out." Although you may feel dizzy, you do not feel as though you or your surroundings are moving. Light-headedness often goes away or improves when you lie down. If light-headedness gets worse, it can lead to a feeling of almost fainting or a fainting spell (syncope). You may sometimes feel nauseated or vomit when you are light-headed.
• Vertigo is a feeling that you or your surroundings are moving when there is no actual movement. You may feel as though you are off balance, spinning, whirling, falling, or tilting. When you have severe vertigo, you may feel very nauseated or vomit. You may have trouble walking or standing, and you may lose your balance and fall.

Although dizziness can occur in people of any age, it is more common among older adults. A fear of dizziness can cause older adults to limit their physical and social activities. Dizziness can also lead to falls and other injuries.

Light-headedness

It is common to feel light-headed from time to time. Brief episodes of light-headedness are not usually the result of a serious problem. Light-headedness often is caused by a momentary drop in blood pressure and blood flow to your head that occurs when you get up too quickly from a seated or lying position (orthostatic hypo tension). Ongoing light-headedness may mean you have a more serious problem that needs to be evaluated.

Light-headedness has many causes, including:

• Allergies.
• Illnesses such as the influenza (flu) or colds. Home treatment of your flu and cold symptoms usually will relieve light-headedness.
• Vomiting, diarrhea, fevers, and other illnesses that cause dehydration.
• Very deep or rapid breathing (hyperventilation).
• Anxiety and stress.
• The use of tobacco, alcohol, or illegal drugs.

A more serious cause of light-headedness is bleeding. Most of the time, the location of the bleeding and the need to seek medical care are obvious. But sometimes bleeding is not obvious (occult bleeding). You may have small amounts of bleeding in your digestive tract over days or weeks without noticing the bleeding. When this happens, light-headedness and fatigue may be the first noticeable symptoms that you are losing blood. Heavy menstrual bleeding also can cause this type of light-headedness.

Sometimes the cause of light-headedness is an abnormal heart rhythm (arrhythmia), which can cause fainting spells (syncope). Unexplained fainting spells need to be evaluated by a doctor. You can check your heart rate by taking your pulse.

Many prescription and non-prescription medicines can cause light-headedness or vertigo. The degree of light-headedness or vertigo that a medicine causes will vary.

Vertigo

Vertigo occurs when there is conflict between the signals sent to the brain by various balance- and position-sensing systems of the body. Your brain uses input from four sensory systems to maintain your sense of balance and orientation to your surroundings.

• Vision gives you information about your position and motion in relationship to the rest of the world. This is an important part of the balance mechanism and often overrides information from the other balance-sensing systems.
• Sensory nerves in your joints allow your brain to keep track of the position of your legs, arms, and torso. Your body is then automatically able to make tiny changes in posture that help you maintain your balance (proprioception).
• Skin pressure sensation gives you information about your body's position and motion in relationship to gravity.
• A portion of the inner ear, called the labyrinth, which includes the semicircular canals, contains specialized cells that detect motion and changes in position. Injury to or diseases of the inner ear can send false signals to the brain indicating that the balance mechanism of the inner ear (labyrinth) detects motion. If these false signals conflict with signals from the other balance and positioning centres of the body, vertigo may occur.

Common causes of vertigo include:

• Inner ear disorders, such as benign paroxysmal positional vertigo (BPPV), Ménière's disease, vestibular neuritis, or labyrinthitis.
• Injury to the ear or head.
• Migraine headaches, which are painful, debilitating headaches that often occur with vertigo, nausea, vomiting, and sensitivity to light, noise, and smell.
• Decreased blood flow through the arteries that supply blood to the base of the brain (vertebrobasilar insufficiency).

Less common causes of vertigo include:

• A non-cancerous growth in the space behind the eardrum (cholesteatoma).
• Brain tumours and cancer that has travelled from another part of the body (metastatic).

Immediate medical attention is needed if vertigo occurs suddenly with a change in speech or vision or other loss of function. Vertigo that occurs with loss of function in one area of the body can mean a problem in the brain, such as a stroke or transient ischemic attack (TIA).

Alcohol and many prescription and non-prescription medicines can cause light-headedness or vertigo. These problems may develop from:

• Taking too much of a medicine (over medicating).
• Alcohol and medicine interactions. This is a problem, especially for older adults, who may take many medicines at the same time.
• Misusing a medicine or alcohol use disorder.
• Drug intoxication or the effects of withdrawal.