What are brain lesions?

Brain lesions are a type of damage to any part of brain. Lesions can be due to disease, trauma or a birth defect. Sometimes lesions appear in a specific area of the brain. At other times, the lesions are present in a large part of the brain tissue. At first, brain lesions may not produce any symptoms. As lesions worsen with time, the symptoms become more noticeable.

How does the brain work?

The brain controls thoughts, memory, speech, movements of the limbs, and organ function. There are many parts to the brain, and each section has a specific role to play in the human body.

Four lobes make up the brain:

Frontal lobe - the largest of the four lobes, is responsible for the body’s motor skills, such as voluntary movement, language, and intellectual and behavioral functions. This area controls memory, intelligence, concentration, temper and personality.

Temporal lobe - located on each side of the brain at ear level, is important for hearing, memory and speech.

Parietal lobe - at the center of the brain, is where sensory information like heat, pressure and pain is received and interpreted.

Occipital lobe - found at the back of the brain, is primarily responsible for vision.

What causes brain lesions to develop?

Brain lesions can be caused by many different triggers. The following factors put a person at greater risk to get brain lesions:

  • Aging
  • Family history of brain lesions. The risk increases if someone else in the family has had the condition.
  • Vascular conditions, such as stroke, high blood pressure, and cerebral artery aneurysms
  • Trauma to the brain, which can cause internal bleeding. If not remedied, it could lead to death.
  • Infections, harmful germs or bacteria in the brain. These can cause diseases like meningitis and encephalitis (both types of swelling (inflammation) of the brain).
  • Tumors that either start in the brain (primary tumors) or travel there (metastatic) via blood or lymphatic vessels
  • Autoimmune diseases, such as lupus and multiple sclerosis. These result when the body’s antibodies start to attack the body’s own tissues, such as those tissues in the brain.
  • Plaques, or excess build-up of abnormal protein in the brain tissues or in the blood vessels, slowing down the supply of blood to the brain, as seen in clogged arteries. Alzheimer’s disease, a condition that affects a person’s memory, thinking and behavior, develops because of plaques in brain tissues. Multiple sclerosis can also cause plaques in the brain secondary to damaged tissue.
  • Exposure to radiation or certain chemicals that increase the chance of tumors and lesions in the brain
  • Toxins, such as excessive amounts of alcohol or cigarette smoke, in the body. Other toxic substances are elevated levels of ammonia and urea in the body due to kidney issues (can affect brain function but may not show discrete brain lesions).
  • Poor diet, especially eating foods with excess fats and cholesterol

What diseases cause brain lesions?

  • Stroke, vascular injury, or impaired supply of blood to the brain is perhaps the leading cause of lesions on the brain.
  • Multiple sclerosis, or MS, is a disease where brain lesions are located in multiple sites of the brain. Those suffering from MS have significant problems with motor and sensory functions.
  • Lupus, an autoimmune disease, affects almost all systems of the body ranging from skin to heart, liver, muscles and brain. Brain lesions are typically a symptom of this disease.
  • Tumors are also a cause of brain lesions and abnormal growth of brain cells.

What are the symptoms of brain lesions?

Symptoms of brain lesions vary depending on the type of lesion, its extent, and where it is found. Everyone is different and symptoms will vary in individual cases. Many lesions, however, may be in areas of the brain that don’t produce symptoms.

Typical symptoms may include:

  • Headaches are usually the first symptom to appear with brain lesions. The pain appears suddenly and worsens as time passes. Over-the-counter medicine usually offers no relief for the pain.
  • Nausea and possible vomiting
  • Impaired movement, if the lesion affects the part of the brain responsible for motor skills
  • Lack of concentration, the inability to make quick decisions, and agitation
  • Delayed speech, blurred vision, and impaired hearing
  • Involuntary movements of body parts, which may progress to convulsions in severe cases

The following symptoms are specific to lesions of the frontal lobe:

  • Absence of sense of smell, usually limited to one nostril
  • Speech impairment
  • Loss of motor activity on one or both sides of the body
  • Behavioral changes

The following symptoms are specific to lesions of the temporal lobe:

  • A change in behavior and emotions
  • Disruption in the sense of smell, taste, and hearing
  • Language and speech disorders
  • Problems with field of vision
  • Forgetfulness and the inability to focus

The following symptoms are specific to lesions of the parietal lobe:

  • Loss of sensations like touch
  • Astereognosis, or the inability to identity things placed in the hand
  • Weakening of language development

The following symptoms are specific to lesions of the occipital lobe:

  • Changes in vision

Last reviewed by a Cleveland Clinic medical professional on 05/07/2018.

References

  • American Association of Neurological Surgeons. Anatomy of the Brain. www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Anatomy-of-the-Brain Accessed 5/11/2018.
  • American Association of Neurological Surgeons. Cerebrovascular Disease. www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Cerebrovascular-Disease Accessed 5/11/2018.
  • National Institute of Neurological Disorders and Stroke. Brain Basics: Know Your Brain. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Know-Your-Brain Accessed 5/11/2018.

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