Digestive system, Opens dialog

Taking a Pulse (Heart Rate), Opens dialog

Overview

Dizziness is a word that's often used to describe two different feelings. It's important to know exactly what you mean when you say "I feel dizzy." 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." You may feel dizzy. But you don't feel as though you or your surroundings are moving. The feeling often goes away or improves when you lie down. If it gets worse, it can lead to a feeling of almost fainting or to 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. You may feel very nauseated or vomit. You may have trouble walking or standing. And you may lose your balance and fall.

Dizziness can occur in people of any age. But it's 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's common to feel light-headed from time to time. Brief bouts of light-headedness aren't usually caused by a serious problem. Light-headedness often is caused by a quick drop in blood pressure and blood flow to your head. This can occur when you get up too quickly from a seated or lying position (orthostatic hypotension). Light-headedness that lasts may mean that you have a more serious problem that needs to be checked.

Light-headedness has many causes. They include:

• Allergies.
• Illnesses such as influenza (flu) or colds.
• Vomiting, diarrhea, fevers, and other illnesses that cause dehydration.
• Very deep or rapid breathing (hyperventilation).
• Anxiety and stress.
• The use of tobacco, alcohol, cannabis, or other drugs.
• Medications that cause drowsiness, like opioids, sleeping aids, and muscle relaxers.

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 clear. But sometimes bleeding isn't obvious (occult bleeding). You may have small amounts of bleeding in your digestive tract (Figure 1) over days or weeks without noticing the bleeding. When this happens, light-headedness and fatigue may be the first signs 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). This can cause fainting spells (syncope). Unexplained fainting spells need to be checked by a doctor. You can check your heart rate by taking your pulse (Figure 2).

Many prescription and non-prescription medicines can cause light-headedness or vertigo.

Vertigo

Vertigo occurs when there is conflict between the signals sent to the brain by the different systems of the body that sense balance and position. 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. It 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 can then make tiny changes in posture that help you keep your balance.
• 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 problems of the inner ear can send false signals to the brain. They can tell the brain 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. Examples are benign paroxysmal positional vertigo (BPPV), Ménière's disease, vestibular neuritis, and labyrinthitis.
• Injury to the ear or head.
• Migraine headaches. They 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).
• Problems in the brain, such as a stroke or a 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 (overmedicating).
• Alcohol and medicine interactions.
• Misusing a medicine or alcohol use disorder.
• Drug intoxication or the effects of withdrawal.