Ask an Expert: Is it a stroke, or something else?

Q: If you have only one symptom of a stroke, or only mild symptoms, how do you know it’s a stroke and not something else? Will symptoms eventually appear that make it clear you've had a stroke? What other conditions cause stroke-like symptoms?

Answer from Ted Lowenkopf, M.D., medical director of Providence Stroke Center:

You can't always know, quickly and with certainty, that you've experienced a stroke. The sudden onset of stroke symptoms usually makes it very clear that a stroke has occurred. But other medical conditions can cause similar symptoms. And in some cases, it can be difficult even for health providers to determine whether the symptoms are the result of a stroke or a different problem.

A CT scan at the emergency department generally clears up this confusion. An MRI is even more sensitive for detecting recent brain injury from stroke.

But the important point is this: If you ever find yourself wondering if you, a loved one, a co-worker or perhaps a stranger has experienced a stroke, do not wait until symptoms become "clear." This is not a time for delay or for puzzling through possible causes on your own. Immediately call 911, no matter what the hour. This holds true whether you notice only a single symptom or a few mild symptoms.

Time is of the essence with stroke. The more minutes that pass, the more likely the chance of permanent brain injury and disability. Rapid medical treatment can help preserve brain function and prevent disability.

Symptoms of stroke
If you notice even one of these symptoms, it could indicate a stroke:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion or trouble speaking or understanding
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking, dizziness, loss of balance or coordination
  • Sudden severe headache, with no known cause

However, other health conditions can cause similar symptoms: 

  • Migraine headaches can cause vision loss (visual aura) or visual disturbances such as streaky or flickering light; numbness or tingling (sensory aura); limb weakness; slurred speech – and, of course, severe headache.
  • Seizures, when mild, may sometimes present solely as numbness and tingling, or weakness or shakiness of an arm or leg. After a severe, full-body seizure – with overall shaking and loss of consciousness – a person may experience weakness on one side of the body.
  • Brain tumors, because of mass effect on brain tissue, can cause headache, weakness or loss of feeling in the arms or legs, unsteady walking, changes in vision and changes in speech.
  • Bell's palsy, a sudden paralysis or weakening of muscles on one side of the face, can cause facial drooping. This is due to damage to a nerve outside the brain, not a stroke.
  • Inner-ear problems can affect balance.
  • Vision disturbances, such as acute glaucoma or retinal tears, can cause sudden blurred vision or visual loss.
  • Multiple sclerosis attacks can produce symptoms identical to stroke. In this case, symptoms emerge due to inflammatory injury to the brain, not due to decreased blood flow.
  • Even the flu can cause weakness, dizziness and headache.

Think of stroke as a “brain attack”
Seeking immediate medical care for a suspected stroke is just as important as seeking immediate medical care for a suspected heart attack. Think of stroke as a brain attack.

It can be difficult and scary to feel that you must make a judgment call about going to the emergency room, so we in the stroke field uniformly prefer that you err on the side of caution: We want you to call 9-1-1.

If it is a stroke, there are several advantages to quick action:

  • The more time that goes by, the more brain damage occurs. The less time, the less damage. Time is brain!
  • The first three hours after the onset of a stroke are a critical window for beginning our best treatment for the most common type of stroke. If you are a candidate for this type of treatment, the earlier you receive it, the better.
  • Doctors can screen for and treat risk factors such as high blood pressure and high cholesterol to help prevent further strokes.
  • Medical monitoring can help you avoid complications, which can occur after even a mild stroke. Possible complications of stroke include bleeding and swelling in the brain; swallowing difficulties that can lead to pneumonia; and blood clots arising from a reduction in physical activity because of the stroke’s effects on balance or muscles.

If it is not a stroke, seeking immediate care will still benefit you, allowing you to find out what is causing your symptoms so that doctors can guide you to appropriate care.

Want more information?
See FAST: Save a life for tips to help prevent and recognize stroke.

Two very fine sources of additional information are the American Stroke Association and the National Stroke Association.