Lesions on the brain: causes, symptoms, diagnosis and treatment

Lesions on the brain: causes, symptoms, diagnosis and treatment
May 17, 2014 4:47 AM

Lesions on the brain what are they? Human brain is the most complex thing known to human being. It’s truly a gift of nature and the centre of all human activities. A healthy brain ensures healthy life but if anything goes wrong with this organ, things go seriously wrong. One such condition is lesions on brain.

Brain lesions can be defined as destruction or damage of any part of brain. Lesions can be due to any disease, trauma or it might be the result of some birth defects. Such lesions might be localized to specific area of brain or might include a large part of brain tissues. Usually the lesions of brain are insignificant at first. They’re so insignificant at first to produce any symptom. But these lesions mostly worsen with time, so does their associated symptoms.

What areas the types of brain lesions?

Before we can move on to know the different types of brain lesions we need to know a little about the normal anatomy of human brain. Human brain is an organ present in skull, everyone knows this much.

Structurally human brain is made upon of two main types of cells: neurons and glial cells.

Neurons act as the structural and functional units of human brain. These units exchange information among each other, process and integrate this information and help us make decisions leading to voluntary and involuntary actions.

These cells, in turn, are made of two major components: the cells bodies meant for processing information and cell fibers meant for carrying electrical impulses. Glial cells on the other hand are supporting structures in the brain. These cells provide neuronal cells with support, nutrition and a proper environment meant for proper functioning. These cells also consist of cell bodies and cell fibers.

All these cells (both neuronal cells and glial cells) are so arranged in the brain that all the cell fibers lie in one part and the cell bodies lie in the other.

So structurally brain can be divided into two distinct areas: The white matter that contains all the neuronal fibers and gray matter that contains all the cells bodies. Here we toss the structural classification of brain lesions.

If these lesions occur in white matter they are called white matter lesions and if they occur in gray matter they are called gray matter lesions. Functionally brain can be divided into different lobes (areas) with each lobe meant for carrying out specialized functions. There are namely four lobes in human brain: frontal, parietal, temporal and occipital.

This is the functional classification of human brain.

Frontal lobe is mostly concerned with planning of movements and their execution.

Parietal lobe is mostly concerned with receiving and interpreting sensory information like heat, pressure, pain etc.

Temporal lobe is associated with controlling activities like hearing and speech.

Occipital lobe is mostly responsible for vision. So the lesions can also be classified on functional basis depending on the type of brain lobe that is affected by the lesion. Each lobe lesion present with different symptoms and has different underlying causes as well.

Yet another way to classify brain lesions is according to the type of insult.

Brain lesions can be classified into following types depending on the nature of insult:

Lesions due to aging

Aging is an inevitable process. It affects all parts of the body and human brain is no exception. Under normal conditions total number of cells that die are replaced by new cells and equilibrium is maintained this way. But as a person ages, the death of neuronal cells outmatches the generation of new cells. This is when the person starts to exhibit symptoms of brain lesions like forgetfulness, agitation and loss of concentration.

Genetic predispositions

Sometimes the lesion develops due to no apparent illness. The most tentative explanation of brain lesions in such conditions is genetic abnormalities. Some brain lesions like neurofibromatosis show strong genetic predisposition.

Lesions due to vascular injury

Human brain is very sensitive to hypoxia i.e. decreased supply of oxygen to the tissues. Other tissues of body can withstand low supply of blood and oxygen for as much as several hours but brain cells start to die within a few minutes of vascular injury or impaired supply of blood. Such lesions are very common in conditions like stroke, high blood pressure and cerebral artery aneurysms.

Traumatic lesions

Sometimes the lesion of brain is the results of some traumatic injury. A blow to head can have two consequences. First, a direct blow can directly cause damage to brain- this condition is quite uncommon. Second, the internal bleeding that follows traumatic blow to head is collected within the head leading to compression of brain vessels, tissue hypoxia and ultimately death.

Lesions due to infections

Sometimes the brain lesions are the result of some harmful organism causing diseases like brain abscesses, meningitis and encephalitis.

Lesions due to tumors

Sometimes the brain lesions are the result some tumors that might involve different areas of brain. Brain tumors might be of two main types. They might have originated within the brain itself or might have travelled via blood or lymphatic vessels to the brain tissues.

Lesions due to autoimmunity

Sometimes the lesions are the result of some autoimmune disease in which antibodies produced in the body start to affect body’s own tissues, brain in this case. The most common diseases that cause brain lesions include systemic lupus erythematosus and multiple sclerosis.

Lesions due to plaques

Plaques are aggregations of some unwanted materials at certain proteins. Plaques can develop within the blood vessels, impeding the supply of blood to the brain, as seen in atherosclerosis. Plaques might be present with the brain tissues themselves causing damage to the brain architecture and function. Such plaques are present in Alzheimer’s disease that develops due to the accumulation of abnormal protein plaques in brain tissues.

Lesions due to toxins

Brain injury might be the result of certain toxin. The most common toxin that affects human brain is alcohol. Another toxic substance is elevated level of ammonia and urea, a situation which develops in conditions involving impairment of kidney functions.

What are the causes of brain lesions?

The brain lesions can develop due to a number of reasons.

Most prevalent causes of brain lesions are mentioned below:

  • Stroke, vascular injury or impaired supply of blood to the brain is perhaps the leading cause of lesions on the brain. These vascular events might be secondary to conditions like hypertension and atherosclerosis.
  • Trauma is another important cause of brain lesions. As mentioned before, trauma can either directly destroy brain tissues or can cause compression and delay of brain blood supply due to the formation of hematoma.
  • Sometimes inflammation causes brain lesions. This is common in conditions like meningitis, irritable bowel syndrome and neurocystecercosis.
  • Autoimmune diseases make the most prevalent cause of brain lesions in current ages. Normally the body produces protective chemicals (antibodies) and cells only against foreign invaders. But in the case of autoimmune diseases, the body starts to produce toxins against its own tissues. In the case of brain lesions the affected tissues are the several parts of brain. There is a long list of autoimmune diseases that might cause brain lesions a few of them include:
    • Multiple sclerosis - As the name shows this disease contains brain lesions in multiple sites of the brain. The individual has significantly impaired motor and sensory functions.
    • Lupus - Lupus is another autoimmune disease that deserves a special mention here. This disease affects almost all systems of body ranging from skin to heart, liver, muscles and brain. The lesions due to lupus present as headaches, fever, fatigue, seizures and coma.
    • Tumors are also very important cause of brain lesions and the abnormally growing cells in these tumors can adversely affect the structural and functional integrity of brain cells.

What are the risk factors?

Following are the risk factors that can increase the chance for an individual to get brain lesions:

  • Increasing age.
  • Any activity involving rapid acceleration or deceleration or any other activity that might increase the chance of injury to the head.
  • Infections caused by viruses, bacteria and worms also increase the chances for an individual to get brain lesions.
  • A positive family history of brain lesions is an important risk factor because this condition mostly runs in families.
  • Exposure to radiations or certain chemicals that increase the chance of tumors and lesions in the brain.
  • Cigarette smoking.
  • Too much consumption of alcohol.
  • Eating a diet rich in fats and cholesterol.
  • Exposure to environmental toxins.

What are the symptoms of brain lesions?

The exact signs and symptoms of brain lesions depend on the type of lesion, its extent and the area of brain involved. We’ll first discuss generalized symptoms that are not helpful in localizing the site of brain lesion but if most of these symptoms appear out of the blue then you should suspect something serious and rush to your doctor for proper checkup.

The non-specific symptoms of brain lesions include:

  • An unexplained headache is perhaps the most common and the first to appear symptom in brain lesions. The headache associated with brain lesions appears out of the blue. It also gets severe with the passage of time and is quite resistant to conventional treatment.
  • Most of the patients with brain lesions complain of nausea.
  • Some people also complain of vomiting. Vomiting progresses with the progression of the disease.
  • Poor mental status might be another important of brain lesions. If the brain lesions involve the motor system then the most important symptom is difficult in movement. If the lesions involve sensory portions of brain then the dominant symptoms are sensory ataxia.
  • Lack of concentration, agitation and inability to do make quick decisions is another indicative of underlying brain injury.
  • If the lesions occupy the areas of brain involved with speech, vision or hearing then you might experience associated symptoms like delayed speech, blurred vision and impaired hearing.
  • In severe cases the patient may also experience involuntary movements of body parts that may progress to convulsions. The symptoms mentioned so far and generalized symptoms of brain lesions and with the help of these symptoms the precise site of brain lesions can’t be localized. However, the localization of brain lesions is possible by assessing certain symptoms.

The symptoms associated with certain areas of brain are as follows:

Lesions of temporal lobe

Following are the most important symptoms seen in the case of lesions of temporal lobe:

  • You might experience change in your behavior and emotions.
  • You might face hallucination of the sense of smell, taste and hearing. This phenomenon is called temporal epilepsy.
  • Language and speech disorders are very common among individuals with temporal lesions.
  • Some visual field defects do exist.
  • Forgetfulness, loss of concentration and awareness are also important symptoms of temporal lobe lesions.

Lesions of frontal lobe

Following are the most important localizing symptoms of the lesions of frontal lobe:

  • The patient usually present with complaints of absence of sense of smell and this usually limited to one nostril.
  • Another important symptom is impairment of speech.
  • The most important sign that distinguished frontal lobe lesions from the rest of cerebral lesions is motor involvement. Loss of motor activity, on one side or both sides of the body, might be seen in patients with frontal lobe lesions.

Lesions of parietal lobe

Following are the most important symptoms of the parietal lobe lesions:

  • There may be loss of sensations like touch.
  • The patient might be unable to identity things placed in hand. This phenomenon is called Astereognosis.
  • There may be impairment of language development.

Lesions of occipital lobe

Any lesions of occipital lobe typical lead to the development of symptoms associated with vision. The affected person might experience blurring of vision. The vision usually worsens over time and optical corrections don’t seem to help much. In some cases the person is unable to understand the meaning of what he sees. In extreme cases it can lead to total blindness.

Can brain lesions cause death?

Brain is the center of life and it is so terrifying to even think of lesions in the brain, and even rightly so. The first thing that comes to mind when anyone hears of brain lesions is death.

Can brain lesions cause death?

This question is very important and must be answered. Well, death due to brain lesions depends on a number of factors like the extent of lesion, its locations etc. Most of the lesions develop symptoms but don’t cause death. But such symptoms do decrease the overall quality of life and life expectancy.

On the other hand, lesions in the vital areas of brain for instance in the areas of the brain meant for controlling normal respiration or heart rhythm can cause immediate death. So, yes brain lesions can cause death and they must not be taken lightly.

How are brain lesions diagnosed?

There are three basic steps in the proper diagnosis of brain lesions: proper history complete examination and further investigations.

The first that a doctor would do is asking the patient about his problem. He would ask the patient questions like what the problem is; when did this all started; have the symptoms worsened or improved; is there any way the symptoms improve or worsen and so on.

For example if patient complaints of poor vision that has been worsening over time and tells the doctor that optical corrections are not doing much good then the doctor should divert his attention to some underlying lesion of brain in the visual cortex.

Taking a precise history is very important because a careful history can help doctor reach a preliminary diagnosis without having to blindly prescribing bunch of investigations and tests to the patient.

The second important component of proper diagnosis is proper physical examination. This would help the doctor in localization of the lesion. For example if a patient complaints of loss of sensation in his hands then the cause might be a lesion in the parietal lobe. To confirm the preliminary diagnosis doctor will carry out some physical examination tests.

For example to check if the parietal lobe is damaged or not, a doctor might do following tests:

  • He might touch the skin of the patient with hot and cold things.
  • He might touch the skin of the patient with vibrating things.
  • He might pinch the patient as assess him for his feeling of pain.

Once doctor has completed his history and has done a complete physical examination then the next step is to confirm the preliminary diagnosis with imaging techniques like MRI and CT scans. These imaging techniques help in the localization of the lesion and will also help in assessing the extent of damage that lesion has done to the brain. These techniques also help the doctors in planning their strategy regarding the treatment of the patient. For instance patients with minor and isolated lesions might not need some rigorous treatments. Patients with multiple and big lesions, on the other hand, might need some bold treatment choices.

What are the treatments for brain lesions?

The treatment of brain lesions is quite complicated and the exact treatment regime depends on the type of lesion and basic cause.

Following are the treatment options available when it comes to the treatment of uncomplicated brain lesions:

  • If the brain lesion is due to some underlying infection then the basic approach is to eradicate that organism, whether that is bacteria, virus or worms. The treatment of lesions due to bacterial meningitis is the use of appropriate anti-biotics.
  • In the case of suspected stroke and vascular block the basic approach is to act promptly and not allow that clogged vessel to rupture and not allow that lesion to develop in first place. For that purpose vasodilators and cholesterol controlling drugs can be given. But if a clot has already plugged some brain vessel then the option is the use of tissue plasminogen activator, a drug that dissolves the clots.
  • If the basic cause of brain lesion is some tumor then curing that underlying cancerous condition is important. Cure of such cases is almost always very difficult.

The success of treatment depends on proper diagnosis and staging of the disease so that appropriate medicines can be used for the treatment of cancer. In other words, there is no clear cut therapy for brain lesions.

The treatment options depend on the type of lesions and severity of symptoms. Usually medicines can be used to treat the underlying cause. Surgery is also a choice in some cases. In fact the treatment plan for brain lesions is personalized for each individual. A thing that is very important in the treatment of brain lesion patient is post-traumatic rehabilitation. For example a patient will frontal cortex lesions might not be able to move even after treatment so rehabilitation programs help such patients to make up for their structural and functional losses as much as possible.

What is the prognosis?

The prognosis of brain lesions depends on a number of variables like type of lesion, its cause, extend of the disease, type of treatment option used and success of the treatment. Those brain lesions in which minimal brain tissue is damaged and timely treatment is provided, in such conditions the prognosis is usually very good.

However, there are some conditions in which the lesions are relentless and the lesions and symptoms don’t improve even after appropriate diagnosis and proper treatment. Such lesions include that associated with multiple sclerosis, lupus and Alzheimer’s. These lesions usually have a very poor prognosis. But this doesn’t mean that you’ve to give up hope altogether. Proper treatment and timely management can help minimize the symptoms. Also timely treatment can ensure maximum rehabilitation.

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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Published: May 17, 2014 4:47 AM
Next scheduled update: May 17, 2016 4:47 AM
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