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What Causes Dizziness?

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Updated July 02, 2012

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Question: What Causes Dizziness?
Answer:

Dizziness is a general term that can be used to describe more than one feeling. Some people will say they are dizzy when they are feeling lightheaded, "floaty," or as if they might lose consciousness. Some people say they feel dizzy because the room seems to be spinning around. (The latter condition is probably more accurately defined as vertigo.) The sensation of feeling dizzy can be caused by multiple different conditions.

This article will cover common causes of dizziness, but keep in mind that it would be impossible to cover all the different causes of dizziness, and what causes one person to become dizzy may not cause dizziness in others.

Dizziness usually stems from a problem in one of the following body systems:

  • Circulatory -- dizziness can occur if not enough blood flow reaches the brain
  • Neurological -- dysfunction of peripheral nerves, the brain, and or spinal cord can make you feel dizzy
  • Inner ear -- the inner ear is largely responsible for our sense of balance and equilibrium, so disorders of the inner ear can cause dizziness
  • Respiratory -- if we breathe too quickly or deeply, called hyperventilation, we can become dizzy or even pass out

Dizziness can occur in other ways but the cause can usually be grouped into one of the above categories.

Circulatory Causes

More specific circulatory conditions that can cause dizziness include:

  • pregnancy
  • dehydration
  • standing up too quickly (called orthostatic hypotension, a condition that is more common among the elderly and those taking certain medications)
  • a drop in blood pressure caused by a medication
  • internal bleeding

Neurological Causes

Neurological conditions that can cause dizziness include:

  • chronic illnesses, such as multiple sclerosis
  • head or spinal cord injuries

Inner Ear Causes

Vertigo, which is dizziness that usually involves the sensation of spinning, can be caused by the following inner ear conditions:

Respiratory Causes

The main respiratory cause of dizziness is hyperventilation due to anxiety. It can also, more rarely, be caused by an infection or other illness that leads to over-breathing.

Other Causes

Other causes of dizziness can include:

  • low blood sugar
  • a medication you've taken or a side effect caused by combining certain medications
  • motion sickness
  • the consumption of alcohol and/or narcotic pain medication or other controlled substances

While the majority of the time, dizziness is temporary and self-treatable, dizziness can be caused by serious illnesses and injuries, including:

When to See a Doctor

Dizziness caused by motion sickness, by drinking alcohol, or by using prescribed narcotic pain medication does not usually need to be evaluated by a physician. While not necessarily an emergency, dizziness caused by migraines should be evaluated, as should any persistent or unexplained dizziness.

If you experience dizziness after starting a new medication, stop taking the medication and call your doctor as soon as possible.

Stand up slowly to avoid a sudden drop in blood pressure. Talk to your doctor about possible causes of orthostatic hypotension. This condition is not usually an emergency, but the dizziness can lead to injuries from falls and should be treated. A chronic condition called postural orthostatic tachycardia syndrome may need to be ruled out.

If you or someone you are with is hyperventilating, stay calm and take deep breaths. For more information, read: How to Treat Hyperventilation Syndrome.

If you suspect low blood sugar (hypoglycemia), eat something that preferably contains both carbohydrates and protein; if you do not have a snack that contains both, carbohydrates are best. Examples of simple carbohydrates that will quickly raise blood sugar include fruit juice, candy, honey or cake icing. If you suspect that someone you are with has low blood sugar and they become unconscious, do not try to feed them because they may choke and/or aspirate -- instead, call 911.

If you have forgotten to eat and your symptoms subside shortly after eating, you probably do not need to see a doctor. If you are diabetic, however, see your doctor as you may need to adjust your medication to avoid low blood sugar in the future. If you have recurrent episodes of low blood sugar for any reason, you should see a doctor. All suspected cases of low blood sugar should be treated because untreated low blood sugar can lead to serious complications, such as coma and even death. If your symptoms do not subside after eating, your dizziness is likely not the result of low blood sugar.

Go to the emergency room if:

  • you experience dizziness after a head injury or other accident
  • someone you are with loses consciousness and you are unable to wake them
  • you have signs of a stroke, such as one-sided weakness or facial drooping -- postponing treatment in the case of a stroke can lead to serious long-term disability or even death
  • you or someone close to you is having seizures or convulsions
  • you or someone you are with has a severe headache, especially if they describe their headache as being the worst they've ever had
  • you have a high fever, especially if you also have a sore or stiff neck or if you've already tried to bring the fever down using acetaminophen or other measures without success
  • you have had severe diarrhea and/or vomiting and suspect dehydration
  • the dizziness is accompanied by sudden hearing loss
  • you have chest pain, a rapid heart rate, or difficulty breathing

Sources:

American Academy of Otolaryngology - Head and Neck Surgery. Accessed: June 27, 2012 from http://www.entnet.org/HealthInformation/dizzinessMotionSickness.cfm

American Pregnancy Association. Pregnancy and Dizziness. Accessed: June 27, 2012 from http://www.americanpregnancy.org/pregnancyhealth/dizziness.html

Medline Plus. Dizziness. Accessed: June 27, 2012 from http://www.nlm.nih.gov/medlineplus/ency/article/003093.htm

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  3. Ear, Nose, & Throat Disorders
  4. ENT Disorders A - Z
  5. ENT Disorders: D - F
  6. What Causes Dizziness?

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