Brain Lesions

What are brain lesions?

Brain lesions are areas of damaged brain tissue. This kind of damage happens because of brain injuries or medical conditions. A stroke, for example, is a type of brain lesion. Lesions can disrupt the way your brain works, causing a wide range of symptoms, such as weakness, disruption of one or more senses and confusion.

How do brain lesions affect the brain?

When it comes to your brain, communication is everything. Your brain uses electrical and chemical signals to communicate inside your brain itself and with areas throughout your body. When you have a brain lesion, the damage can disrupt communication in the affected brain area(s). The more severe the damage, the greater the disruption.

How lesions affect different areas of the brain

Different areas of your brain control different processes and functions, so the symptoms of brain lesions vary depending on their location. A neurologist or other healthcare provider uses your symptoms to locate where the problem is within your brain. The three main areas of the brain are the cerebrum, cerebellum and brainstem.

Cerebrum

Your cerebrum is the main part of your brain. It has two halves: the left hemisphere and the right hemisphere.

Both hemispheres of your brain have four areas known as lobes. They’re the frontal, temporal, parietal and occipital lobes. There’s also a hidden internal area called the insula, underneath the frontal lobe.

Frontal lobe

Your frontal lobe is at the front of your head. Lesions in your frontal lobe can lead to certain symptoms or conditions, including:

• Trouble with learning.
• Visual-motor function.
• Executive dysfunction and problems with attention (planning, focusing and inhibition).
• Agitation and mood swings.
• Aphasia (Broca’s subtype): Trouble getting words out.
• Weakness or paralysis in a specific area or side of your body.
• Loss of sense of smell (anosmia).

Temporal lobe

Your temporal lobes are on the sides of your head. Lesions in this area of your brain could result in:

• Aphasia (Wernicke’s subtype): Trouble understanding words.
• Auditory processing difficulties.

Parietal lobe

Your parietal lobe is at the top of your head. Lesions in this area could result in:

• Numbness or tingling (although this usually isn’t from your brain, and from the nerves in your limbs).
• Agraphia (inability to write).
• Acalculia (inability to do math).
• Finger agnosia (inability to recognize your own hands and fingers).
• Confusion of left and right.

Insular lobe

Your insular lobe (insula) is hidden just beneath your frontal lobe. Lesions in your insula could cause:

• Loss of sense of taste (ageusia).
• Disruptions of the sympathetic (fight or flight) nervous system and the parasympathetic (rest and digest) nervous system.

Occipital lobe

Your occipital lobe is at the back of your head. Lesions here could result in:

• Cortical blindness (loss of vision because of a problem with your brain rather than your eyes).
• Total color blindness (achromatopsia).
• Face blindness (prosopagnosia).
• Issues with recognizing things you see (visual agnosia).

Cerebellum

Your cerebellum is a densely packed area of brain tissue at the bottom rear of your skull. Symptoms of lesions in your cerebellum include:

• Dysarthria (trouble coordinating the muscles you use to speak).
• Dizziness.
• Paralysis.
• Shaking and tremors.
• Trouble controlling eye movements, leading to vision problems like double vision (diplopia).

Brainstem

Your brainstem is a stalk-like structure that connects your brain to your spinal cord. Lesions on your brainstem can cause problems with your heart rhythm, breathing, blood pressure, eye alignment and more.

What are the most common causes of brain lesions?

Brain lesions can happen with any condition or circumstance that can damage your brain.

Medical conditions that can cause brain lesions include:

• Brain tumors (including cancer).
• Congenital disorders (conditions you have at birth) and metabolic disorders.
• Degenerative brain diseases (especially age-related ones), such as Alzheimer’s disease, Lewy body dementia, Multiple system atrophy, and Parkinson’s disease.
• Immune and inflammatory conditions, such as multiple sclerosis or lupus.
• Infections (such as from microorganisms like bacteria, fungi, parasites or amoeba).
• Genetic conditions such as Huntington’s disease or Wilson’s disease.
• Progressive supranuclear palsy.
• Seizures and epilepsy.
• Strokes or transient ischemic attacks (TIAs).

Injury, trauma and nonmedical circumstances that can cause brain lesions include:

• Concussions and other traumatic brain injuries.
• Medical procedures, such as surgery, radiation therapy or chemotherapy.
• Radiation exposure.
• Heavy metal poisoning or other toxins.

How are brain lesions diagnosed?

A healthcare provider might start to suspect a lesion following a neurological exam. In this exam, a healthcare provider tests muscle strength in your limbs, checks your reflexes and determines if your senses work correctly.

After a neurologic exam, the next step to detect a brain lesion is with imaging scans. Some of the most common imaging technologies that can show these kinds of lesions include:

• Computed tomography (CT) scan.
• Magnetic resonance imaging (MRI) scans.
• Positron emission tomography (PET) scans.

Other tests are also possible, but these are typically used to detect or rule out another condition that could cause similar symptoms. Your healthcare provider is the best person to tell you what tests they recommend and why.

How are brain lesions treated?

Brain lesions can happen for many reasons, which means there are many ways to treat them. Your provider will base their treatment recommendations on the underlying cause of your brain lesion.

Some conditions that cause brain lesions, like a mild concussion, go away on their own. If the lesion isn’t severe, treatments are unnecessary. Rest and reduced activity are often all that you’ll need.

Other conditions that cause brain lesions are treatable in different ways. Infections are often treatable with antibiotics or supportive care. Growths or tumors — especially easy-to-reach ones — may be removable with surgery. Some lesions are very small and don’t cause symptoms or harm.

Unfortunately, there are also times when brain lesions aren’t treatable. This is most likely with lesions that cause severe damage. The same is true for incurable conditions like Alzheimer’s disease.

Because the treatment options can vary, your healthcare provider is the best person to tell you which one(s) they recommend and why.

How can brain lesions be prevented?

Brain lesions are sometimes preventable, depending on the cause. The types of lesions that are most preventable are those that happen because of concussions and traumatic brain injuries. Treating infections in your body promptly can also prevent an infection from spreading to your brain and causing damage.

Some of the most helpful things you can do to prevent brain lesions, or at least reduce your risk of developing them, include:

• Eat a balanced diet. Your diet plays a key role in your circulatory health. Strokes are one of the most common causes of brain lesions, and you can often prevent a stroke, or at least delay when you have one or limit how severe it is.
• Stay physically active and maintain a weight that’s healthy for you. Your weight and activity level can prevent or delay conditions that affect your brain, especially circulatory problems like high blood pressure. Your healthcare provider can tell you the ideal weight range for you and help you plan out how to reach and maintain it.
• Wear safety equipment as needed. Head injuries, especially concussions and traumatic brain injuries, are very common causes of brain lesions. Wearing safety equipment — especially helmets or head-protecting gear — is vital. Seat belts (or similar safety restraints) are also crucial to preventing head injuries. Use these whenever recommended, regardless of whether you’re at work or on your own time.
• Manage your chronic conditions. Many conditions that cause brain lesions are often manageable. An example of this is epilepsy, which you can often manage with medication. Preventing seizures or reducing their severity can help avoid damage to your brain tissue.

When should I see a doctor or healthcare provider?

Brain lesions can indicate you have a severe or even life-threatening issue. For example, a stroke is a time-sensitive medical emergency. If you think someone with you is having a stroke, call 911 or your local emergency services number.

Other symptoms of brain lesions that mean you need medical attention quickly include:

• Sudden, severe headache, especially those that get worse over time or that don’t respond to over-the-counter pain relievers.
• Unexplained vision changes, such as double vision or blurring, flashing lights or spots, distortions, haze or black spots in your vision.
• Seizures that last more than five minutes, or that happen back-to-back without enough time to recover between them.
• Any loss of consciousness following an impact to your head or body, as well as nausea or headache immediately after such an impact.
• Altered consciousness or behavior, such as a person suddenly acting very differently than they usually do.

A note from Cleveland Clinic

Brain lesions can happen for many reasons, making them a very common sign of a brain-related condition. Some lesions are minor and need little or no treatment to heal. Others are more severe and may need medical care, such as surgery. Unfortunately, some lesions are severe, permanent or happen for reasons that aren’t treatable.

Advances in medical imaging mean healthcare providers are better able to detect and analyze brain lesions. These imaging technologies are also key in planning out possible treatments and predicting your case’s possible or likely outcomes. Advances in medicine’s understanding of the brain also offer new possibilities for treatment or recovery from brain lesions and the conditions that cause them.