7 Conditions That Can Mimic a Stroke and How to Tell the Difference

When a person experiences symptoms like slurred speech, weakness, numbness on one side of the body or vision problems, the go-to assumption is that they're having a stroke. But that's not always the case.

A stroke occurs when your brain's blood supply is blocked, either by a blood clot or a ruptured blood vessel. This causes brain cells to die, which leads the parts of the body controlled by those brain cells to lose their function and results in the symptoms mentioned above, per the Centers for Disease Control and Prevention (CDC).

But many other conditions, called "stroke mimics," can share similar symptoms. In fact, up to half of people who go to the hospital for a suspected stroke end up being diagnosed with something else, according to a December 2021 review in ‌Annals of Medicine.‌

Here, learn the most common stroke mimics, their symptoms and how to tell the difference between a stroke and something else.

"A 'stroke mimic' is a term that describes a condition which appears to involve stroke-like symptoms, but there's no evidence of neurological or tissue damage in the brain," says Saima Zafar, MD, a cardiologist at Texas Health Presbyterian Hospital Kaufman.

Common stroke mimic symptoms can include:

• Slurred speech
  
• Confusion
  
• Headache
  
• Dizziness
  
• Weakness or numbness
  
• Vomiting
  

In cases of a stroke or a stroke mimic, these symptoms can come on suddenly, Dr. Zafar says. Below are some of the most common health problems that may be mistaken for a stroke.

Balance problems like peripheral vestibular dysfunction can happen when balance sensors in the ears have problems sending signals to the brain. This can make a person feel dizzy or disoriented, blur their vision or even cause them to stumble or fall. They might also get anxious or nauseous, according to Johns Hopkins Medicine.

Balance disorders can be caused by a number of things, including infections, inner ear problems, certain medications or a brain injury. Anyone can be affected, but they're more common in older adults, per the National Institutes of Health (NIH).

Seizures — sudden, uncontrolled bursts of electrical activity in the brain — account for 13 percent of stroke mimics, per a November 2021 review in the ‌Journal of Clinical Neuroscience‌.

They can cause shaking, confusion or loss of consciousness, as well as stroke-like symptoms like weakness or numbness on one side, trouble speaking or vision problems, Dr. Zafar says.

Seizures are usually caused by the brain disorder epilepsy, but they can also be triggered by an infection, a high fever, low blood sodium or even a lack of sleep, according to the Mayo Clinic. It's also possible for a seizure to occur after a stroke, per the U.K.'s Stroke Association.

While you might not expect a headache to be mistaken for a stroke, nearly 8 percent of stroke mimics are migraines, per the ‌Journal of Clinical Neuroscience‌ review.

Here's why: Migraine headaches can cause severe pain (especially around the temples), nausea, vomiting and sensitivity to light and sound.

"In some cases they can also cause symptoms that mimic a stroke, such as weakness or numbness on one side of the body, difficulty speaking and vision problems," Dr. Zafar says.

Multiple sclerosis (MS) is a life-long condition where damage to the brain and spine causes signaling problems between nerves.

Often, symptoms can come on suddenly, and in some cases, they can look a lot like a stroke, per Johns Hopkins Medicine. Some of the most common early signs include trouble seeing, trouble balancing, weakness and trouble thinking clearly, along with sensitivity to heat, foot numbness and a frequent urge to urinate.

Too-low levels of sodium in the blood, called hyponatremia, can occur when someone takes diuretic medications, drinks too much alcohol, has severe diarrhea or takes certain selective serotonin reuptake inhibitors (SSRIs), according to the Cleveland Clinic.

A person might get a headache or nausea, become confused, have muscle weakness or twitching, have a seizure or have trouble breathing with hyponatremia, Dr. Zafar says.

When blood sugar falls below the normal range (also called hypoglycemia), a person can start to become pale, shaky, sweaty or lightheaded. As it gets worse, the condition can cause stroke-like symptoms including confusion, loss of coordination, slurred speech or blurred vision, per the Mayo Clinic.

Low blood sugar most often occurs in people with diabetes, kidney disease, liver disease or advanced heart disease. But low blood sugar can also occur from heavy alcohol consumption or certain hormonal imbalances or deficiencies. Mild cases of low blood sugar can sometimes even happen after exercising.

Bell's palsy is a neurological disorder that happens when a nerve that controls muscles in the face stops working, usually from an infection or injury. But it can also happen if you have Lyme disease, diabetes or high blood pressure, per Johns Hopkins Medicine.

This can cause sudden facial weakness or paralysis, a drooping eyebrow or mouth, drooling from one side of the mouth or trouble closing one eyelid. This is similar to facial paralysis and drooping that you witness in someone having a stroke, per the American Stroke Association.

"While alarming, [Bell's palsy] is not usually permanent and resolves within a few weeks or months, depending on its severity," Dr. Zafar says.

If you think you or someone you know might be having a stroke, you can use the FAST test, per the CDC. Here is what each letter stands for:

• ‌Face:‌ Ask the person to smile. Does one side of their face droop?
  
• ‌Arms:‌ Ask the person to raise both arms. Does one arm drift forward?
  
• ‌Speech:‌ Ask the person to repeat a simple phrase. Is their speech slurred or strange?
  
• ‌Time:‌ If you see any of these signs, call 911 right away.
  

The sooner someone gets medical attention for a stroke, the better the outcome will be. Whether you are experiencing a stroke or stroke mimic, if you develop these symptoms all of a sudden, emergency treatment is advised.

From there, doctors can determine whether you're having a stroke or a stroke mimic, and treat you accordingly.

That way, if you ‌are‌ having a stroke, "treatment can be administered within three hours of the onset of symptoms, to help reduce damage to brain tissue and prevent functional impairment," Dr. Zafar says.

Even if a person passes the FAST test, stroke-like symptoms warrant immediate medical attention. Just one sign of a stroke should be enough cause to call 911.

Ultimately, it's better to be safe than sorry when it comes to stroke and stroke mimics. If you end up experiencing a stroke mimic, doctors can still help you diagnose the issue, develop a treatment plan and get relief from symptoms, Dr. Zafar says.