Brain lesions facts
Brain anatomy
The brain is responsible for regulation the functions of the body, from the unconscious (controlling blood pressure, heart rate and respiratory rate) to the conscious acts like walking and talking. Add the intellectual processes of thought and the brain is a busy part of the human body.
The brain has many parts. The cerebrum consists of two hemispheres which are responsible for movement, sensation, thought, judgment, problem solving, and emotion. The brain stem sits beneath the cerebrum and connects it to the spinal cord. The brain stem houses the structures that are responsible for the unconscious regulation of the body such as wakefulness, heart and lung function, hunger, temperature control, and swallowing. The cerebellum is located beneath and behind the cerebrum and is responsible for posture, balance, and coordination.
While the brainstem is important in maintaining body function, the cerebrum allows body motion and most importantly, is responsible for all the things that make humans special, like thinking and emotion. There are four lobes in each hemisphere: frontal, parietal, temporal, and occipital.
Brain cells use glucose almost exclusively for their energy needs and unlike other organs in the body, the brain cannot store glucose for future use. If blood sugar levels fall, brain function can be immediately compromised.
The brain gets its blood supply through four major arteries, the right and left carotids and the right and left vertebral arteries. They join together at the base of the brain at the Circle of Willis. Smaller blood vessels then branch out to provide oxygen and glucose rich blood to all regions of the brain.
Brain Cell AnatomyThe brain is composed of billions of cells that use chemicals and electricity to communicate between themselves and the rest of the body. There are two major types of cells, neurons and glial cells; there are subtypes of these cells.
NeuronsWhat are brain lesions?
A brain lesion describes damage or destruction to any part of the brain. It may be due to trauma or any other disease that can cause inflammation, malfunction, or destruction of a brain cells or brain tissue. A lesion may be localized to one part of the brain or they may be widespread. The initial damage may be so small as to not produce any initial symptoms, but progresses over time to cause obvious physical and mental changes.
A brain lesion may affect the neuron directly or one of the glial cells thereby indirectly affecting neuron functions.
What causes brain lesions?
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.
What are the signs and symptoms of brain lesions?
Symptoms of a brain lesion depend upon what part of the brain is affected. Large parts of the brain can be involved in some diseases and there may be relatively few symptoms. Alternatively, very tiny lesions may be catastrophic if they occur in a critical part of the brain. For example, the reticular activating system (RAS) is a tiny area located within the brainstem that is effectively the master on/off switch of the brain. If a midbrain stroke affects this area, the result is permanent coma. A patient needs the RAS and one functioning hemisphere of the cortex to be awake. If the patient is unconscious, then the RAS isn't working or there is significant damage to both sides of the brain.
Initial signs and symptoms of a brain lesion are often non-specific and may include:
If any of these symptoms arise suddenly, the person should be evaluated immediately, usually in an emergency department that is well equipped (CT scanner, MRI, easy access to neurosurgeons and neurologists).
How are brain lesions diagnosed?
The diagnosis of a brain lesion begins with the health care practitioner taking a history and asking the patient questions about the symptoms such as:
Depending upon the circumstances, the patient may not have insight or may not remember the symptoms or complaints, and it may be up to a family member, caregiver, or friend to supply the appropriate information.
Medical history and physical exams
Past medical history of the patient, exploring associated symptoms and complaints may be helpful in determining the diagnosis.
Physical examination is very helpful in trying to localize a potential brain lesion. A careful neurologic exam may be useful in finding weakness, change in sensation (including light touch, pain, vibration, and position sense), and coordination. Mental status, agility, other organ systems are often assessed. For example, patients who have an irregular heart rate called atrial fibrillation are at risk for stroke. Stroke risk may also be increased in patients with carotid stenosis and the health care practitioenr may listen over the neck for a bruit (an abnormal sound made by blood rushing through a narrowed carotid artery).
Imaging and other testsDepending upon the clinical situation, imaging of the brain such as computerized tomography (CT) andmagnetic resonance imaging (MRI) may be useful in making the diagnosis of a brain lesion. Angiography can be added to either CT or MRI to visualize the blood vessels in the brain.
Lumbar puncture (spinal tap) is often considered to evaluate the cerebrospinal fluid (CSF) for infection, bleeding, or abnormal proteins; depending upon the clinical situation.
Blood tests are usually preformed, to explore any illnesses that can also involve the brain.
What are brain lesions?
A brain lesion describes damage or destruction to any part of the brain. It may be due to trauma or any other disease that can cause inflammation, malfunction, or destruction of a brain cells or brain tissue. A lesion may be localized to one part of the brain or they may be widespread. The initial damage may be so small as to not produce any initial symptoms, but progresses over time to cause obvious physical and mental changes.
A brain lesion may affect the neuron directly or one of the glial cells thereby indirectly affecting neuron functions.
What causes brain lesions?
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.
What are the signs and symptoms of brain lesions?
Symptoms of a brain lesion depend upon what part of the brain is affected. Large parts of the brain can be involved in some diseases and there may be relatively few symptoms. Alternatively, very tiny lesions may be catastrophic if they occur in a critical part of the brain. For example, the reticular activating system (RAS) is a tiny area located within the brainstem that is effectively the master on/off switch of the brain. If a midbrain stroke affects this area, the result is permanent coma. A patient needs the RAS and one functioning hemisphere of the cortex to be awake. If the patient is unconscious, then the RAS isn't working or there is significant damage to both sides of the brain.
Initial signs and symptoms of a brain lesion are often non-specific and may include:
If any of these symptoms arise suddenly, the person should be evaluated immediately, usually in an emergency department that is well equipped (CT scanner, MRI, easy access to neurosurgeons and neurologists).
How are brain lesions diagnosed?
The diagnosis of a brain lesion begins with the health care practitioner taking a history and asking the patient questions about the symptoms such as:
Depending upon the circumstances, the patient may not have insight or may not remember the symptoms or complaints, and it may be up to a family member, caregiver, or friend to supply the appropriate information.
Medical history and physical exams
Past medical history of the patient, exploring associated symptoms and complaints may be helpful in determining the diagnosis.
Physical examination is very helpful in trying to localize a potential brain lesion. A careful neurologic exam may be useful in finding weakness, change in sensation (including light touch, pain, vibration, and position sense), and coordination. Mental status, agility, other organ systems are often assessed. For example, patients who have an irregular heart rate called atrial fibrillation are at risk for stroke. Stroke risk may also be increased in patients with carotid stenosis and the health care practitioenr may listen over the neck for a bruit (an abnormal sound made by blood rushing through a narrowed carotid artery).
Imaging and other testsDepending upon the clinical situation, imaging of the brain such as computerized tomography (CT) andmagnetic resonance imaging (MRI) may be useful in making the diagnosis of a brain lesion. Angiography can be added to either CT or MRI to visualize the blood vessels in the brain.
Lumbar puncture (spinal tap) is often considered to evaluate the cerebrospinal fluid (CSF) for infection, bleeding, or abnormal proteins; depending upon the clinical situation.
Blood tests are usually preformed, to explore any illnesses that can also involve the brain.
Source: http://www.rxlist.com
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.
Source: http://www.rxlist.com
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