Signs and Symptoms of a Brain Tumor

Headache, Seizure, and Fainting in Brain Tumors

woman with headache
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Although there are many different types of brain tumors, people with cancer in their brain share many symptoms. These symptoms can result from tumor invasion and damage to specific brain regions, compression of nearby brain regions, or by globally increased pressure within the skull (intracranial pressure). To diagnose someone as having a brain tumor, doctors rely on the questions they ask, a thorough examination, and additional tests such as magnetic resonance imaging (MRI).


Many people begin worrying about the possibility of a brain tumor due to the presence of a headache. Headache is common, but not universal, among patients with brain tumors. About one half of patients have another symptom that is more severe.

Headaches are more concerning for tumor if they come on with nausea and vomiting, or if they worsen when lying flat. These are signs of increased intracranial pressure (ICP). Lying flat may reduce the amount of blood that flows out of the skull, thereby increasing pressure and pushing on pain fibers in the tissues that surround the brain. Other maneuvers that increase ICP include sneezing, coughing or bearing down as if having a bowel movement.

A typical headache due to tumor is felt on both sides of the head, but is worse on the side of the tumpr. The headache is usually dull and persistent, though in some cases it may also be throbbing.

Of course, most headaches are not due to brain tumors, and even if all of these characteristics are present, there is a strong possibility that a headache is due to some other cause.

For example, nausea is often felt during migraines, as is pain that is worse on one side.


A neoplasm can irritate part of the brain, leading to abnormal electrical activity and seizures. In two large reviews, seizures were found to be the first sign of a primary brain tumor in about 18 percent of cases, and were present in about a quarter of patients at the time of diagnosis.

The risk seems lower in metastatic brain tumors (cancer that arises from another part of the body) at about ten percent. Because the tumor always causes irritation in the same spot, the seizure is likely to appear the same each time.

Loss of Consciousness

Everyone’s intracranial pressure fluctuates from time to time. If the pressure is already high though, these natural fluctuations can cause severe problems. For example, the pressure within the skull may be so high that blood flow to the brain is slowed, and the brain stops getting as much oxygen as it needs. As a result, the brain loses consciousness, and the person blacks out. While there are many other causes of fainting, this is among the most serious. If the pressure increases to the point where blood flow is not enough to sustain consciousness, a coma can result.

As with headaches due to increased intracranial pressure, fainting is more likely to occur with events that increase that pressure, such as coughing, sneezing, or vomiting.

People with a fainting episode may twitch a few times and make people think they are having a seizure. It's important to distinguish these two problems, since the appropriate treatment is very different.

Cognitive Changes

Brain tumors often cause changes in memory, problem solving, spatial ability and even personality. Sometimes these changes are subtle, and may be attributed to more commonplace problems like depression.

Focal Neurological Changes

Most of the symptoms described so far could result from tumors located practically anywhere in the brain. The brain is organized, however, so that different areas control different aspects of thinking and behavior. A tumor in the right hemisphere, for example, could affect movement of the left arm without changing someone’s ability to speak.

Examples of focal neurological deficits include numbness or weakness of just one part of the body, loss of the ability to speak or to understand speech, and loss of mathematical inability. There are many others, but like all of the symptoms discussed so far, they are most concerning in combination with other concerning symptoms and even then may be due to disorders other than brain tumor.

Bottom Line

While there are many symptoms which can raise people’s suspicion for brain tumor, especially in combination, all of these symptoms could also be due to more common and less serious causes. That being said, all of these symptoms are uncomfortable, and because they are potentially signs of tumor, require examination by a medical professional.


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DISCLAIMER: The information in this site is for educational purposes only. It should not be used as a substitute for personal care by a licensed physician. Please see your doctor for diagnosis and treatment of any concerning symptoms or medical condition.

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