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Brain Lesions Definition
A brain lesion is an abnormality seen on a brain-imaging test, such as magnetic resonance imaging (MRI) or a computerized tomography (CT) scan. On CT or MRI scans, brain lesions appear as dark or light spots that don’t look like normal brain tissue.
Usually, a brain lesion is an incidental finding unrelated to the condition or symptom that led to the imaging test in the first place.
A brain lesion may involve small to large areas of your brain, and the severity of the underlying condition may range from relatively minor to life-threatening.
What are the types of Brain Lesions?
There are many types of brain lesions. The brain can be affected by a host of potential injuries that can decrease its function. The type of lesion depends upon the type of insult that the brain receives.
- Aging: Some lesions occur as a result of aging with loss of brain cells as they naturally age and die. If enough cells die, atrophy can occur and brain function decreases. This may present with symptoms of loss of memory, poor judgment, loss of insight and general loss of mental agility.
- Genetic: Lesions related to a person’s genetic makeup, such as people with neurofibromatosis.
- Vascular: Loss of brain cells also occurs with stroke. With ischemic strokes (CVA) blood supply to an area of the brain is lost, brain cells die and the part of the body they control loses its function.
- Bleeding: Strokes can also be hemorrhagic, where bleeding occurs in part of the brain, again damaging brain cells and causing loss of function. Uncontrolled high blood pressure, AV malformations, and brain aneurysms are some causes of bleeding in the brain.
- Trauma: Bleeding in the brain may be caused by trauma and a blow to the head. Bleeding may occur within brain tissue or in the spaces surrounding the brain. Epidural and subdural hematomas describ blood clots that form in the spaces between the meninges or tissues that line the brain and spinal cord. As the clot expands, pressure increases within the skull and compresses the brain.
- Acceleration/deceleration injury: Sometimes trauma can affect the brain with no evidence of bleeding on CT scan. Acceleration deceleration injuries can cause significant damage to brain tissue and connections causing microscopic swelling. Shaken baby syndrome is a good example of acceleration/deceleration type injury, where the brain bounces against the inner lining of the skull.
- Infection and inflammation: Infectious agents resulting in diseases such as meningitis, brain abscesses or encephalitis
- Tumors: Tumors are types of brain lesions and may be benign (meningiomas are the most common) or malignant like glioblastoma multiforme. Tumors in the brain may also be metastatic, spreading from cancers that arise primarily from another organ. Symptoms occur depending upon the location and size of the tumor.
- Immune: Immunologic causes may also affect the brain, for example diseases like multiple sclerosis.
- Plaques: Some investigators suggest that abnormal deposits of material that form plaques may be a type of disease that causes damage and eventual brain cell death in diseases like Alzheimer’s disease.
- Toxins: Toxins may affect brain function and may be produced within the body or may be ingested. The most common ingested poison is alcohol, though other chemicals can adversely affect the brain. Individuals can develop encephalopathy due to a variety of chemicals and substances that build up in the blood stream. Ammonia levels rise in patients with liver failure while patients with kidney failure can become uremic.
- Multiple types: The type of lesion depends upon its cause and symptoms depend upon its location and amount of brain irritation or damage that has occurred. Some brain lesions types may occur from more than one cause, such as Alzheimer’s disease that may be related to plaque formation, brain cell death, and possibly genetics. Research is ongoing and is likely to provide better insights into these various brain lesion types.
Causes Brain Lesions
Often, a brain lesion has a characteristic appearance that will help your doctor determine its cause. Sometimes the cause of the abnormal-appearing area cannot be diagnosed by the image alone, and additional tests or follow-up tests may be necessary.
Among the known possible causes of brain lesions are:
- Brain aneurysm
- Brain AVM (arteriovenous malformation) abnormal connections between blood vessels in the brain
- (both cancerous and noncancerous)
- Encephalitis
- Hydrocephalus (a congenital brain abnormality)
- Multiple sclerosis
- Traumatic brain injury
While brain trauma of any sort may result in a concussion as well as a brain lesion, concussions and brain lesions are not the same thing. Concussions more often occur without ever causing any changes on the CT or MRI and are diagnosed by symptoms rather than imaging tests.
What Are the Symptoms of a Brain Lesion?
Symptoms of a brain lesion vary depending on the type, location, and size of the lesion. Symptoms common to several types of brain lesions include the following:
- Headaches
- Neck pain or stiffness
- Nausea, vomiting, and lack of appetite
- Vision changes or eye pain
- Changes in mood, personality, behavior, mental ability, and concentration
- Memory loss or confusion
- Seizures
- Fever
- Difficulty moving
Treatment for Brain Lesions?
Treatment for brain lesions depends upon the specific diagnosis of the brain lesion.
Can brain lesions be prevented?
Many brain lesions are neither preventable nor predictable. However, general guidelines for health maintenance may help prevent some brain lesions. The same recommendations to help prevent heart disease also are appropriate to help prevent strokes:
- Don’t smoke
- Control high blood pressure, high cholesterol, and diabetes
- Always wear a helmet when participating in activities where the head is exposed to danger (for example, riding a bicycle or motorcycle, skiing, skateboarding, and rollerblading).
- Avoid radiation and environmental toxins may reduce the chances for brain cancer development.
