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.
Symptoms and Causes
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:
- 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
Diagnosis and Tests
How are brain lesions diagnosed?
If symptoms suggest that a person may be suffering from a brain lesion(s), it is important to contact the doctor for an appointment. A doctor will help diagnose and offer treatment options for each patient depending on the extent of the condition.
The doctor will ask questions about the patient’s symptoms and medical history and then perform a physical examination.
In order to find the location of the lesion, the doctor may touch the patient’s skin with hot, cold or vibrating objects, and also may pinch the patient to check for the feeling of pain. Additional tests may also be recommended by the doctor to further assess the condition.
What tests diagnose brain lesions?
After a physical examination, the doctor may also recommend that the patient schedule a diagnostic test, such as a computed tomography, or CT or CAT scan, or magnetic resonance imaging, or MRI. These tests will help the doctor pinpoint the location of the lesion and will also help assess the extent of damage the lesion has caused the brain.
Computed tomography (CT or CAT scan) is a diagnostic image used to evaluate bone, blood and brain tissue. Sometimes, a medication is injected through the patient’s vein to help highlight brain structures. A CT scan uses radiation.
Magnetic resonance imaging (MRI) is a diagnostic test that produces three-dimensional, or 3D, images of the inside of the body using magnetic fields and computer technology. It shows brain tissue detail as well as the brain stem, and cerebellum (posterior brain) better than a CT scan. An MRI of the brain can help determine whether there are signs of prior mini-strokes. A medication (contrast) can also be injected to help high light structures.
Management and Treatment
How are brain lesions treated?
Treatment varies in each individual case depending on the type of lesion, its location, and cause. It is important that a thorough examination be completed by a doctor to develop the appropriate treatment plan.
The treatment options depend on the type of lesions and severity of symptoms. Usually medicines can be used to treat the underlying cause. Surgery may be an option in some cases, such as when the lesions are caused by a brain tumor.
Sometimes, lesions and symptoms don’t improve even after appropriate diagnosis and proper treatment and the goal is to manage symptoms.