There are many ways to acquire
a brain injury. The type of injury can affect just
one part of the brain or several parts that are responsible
for different functions. Each brain injury is unique,
meaning that symptoms can vary widely. There are
two types of brain injury: traumatic and non-traumatic.
Traumatic
Injury
A traumatic injury can be classed
as an open or closed injury. A close injury is cause
when the brain is bounced around in the skull due
to a blow to the head or severe shaking. A closed
motion can cause tearing, shearing or stretching
of the brain tissue. These types of injury are much
more common that open head injuries.
An open injury occurs when an object
such as a bullet, fractures the skull and enters
the brain. These injuries usually damage relatively
localized areas of the brain resulting in specific
damage.
Types of traumatic injuries include:
1.
Contusion
A contusion occurs when there is
bruising of the brain tissue at the site of the fractures
known as coup. It can also occur when other parts
of the brain have shifted in the skull on impact.
A severe blow may cause greater damage to the cells
on the opposite side to where the blow occurred,
which is known as contrecoup.
2.
Diffuse Axonal Injury
This type of injury can be cause
by shaking or strong rotation of the head as in a
car accident or fall. The injury occurs as a result
of traumatic shearing forces that rotate or twist
the axons when the head is rapidly thrown back and
forth as may occur in a road traffic accident or
fall.
This type of injury causes loss
of efficiency in the brain along with slowing down
the speed of thinking and moving due to the disruption
of the brain’s chemical and communication processes.
Non-traumatic Injury
A non-traumatic injury is an injury
that does not occur as a result of trauma. This includes
stroke, tumors, infectious diseases, lack of oxygen
or toxicity.
1.
Stroke
A stroke is an interruption of
blood supply to a section of the brain. If arteries
become blocked, bleed or break, the brain tissue
deteriorates. Types of stroke are:
The after effects of a stroke vary
widely dependent on the part of the brain affected
and extent of blood shortage.
A stroke in the left hemisphere
may result in:
- A degree of paralysis on the
right side
- Loss of feeling on right side
- Reduction in the right field
of vision
- Loss of speech and comprehension
A stroke in the right hemisphere
may result in:
- A degree of paralysis on left
side
- Loss of feeling on left side
- Acting impulsively
- Difficulty expressing emotions
- Short attention span
2.
Anoxic/Hypoxic Injury
These types of injuries occur due
to a lack or complete absence of oxygen in the brain.
These injuries can occur as a result of respiratory
arrests, drowning, heart attacks and poisoning.
- Anoxic Anoxia -
from no oxygen supplied to the brain
- Anemic Anoxia -
blood does not carry enough oxygen to brain
- Atagnant Hypoxia -
the brain receives some but not enough oxygen
- Toxic Anoxia -
toxins or metabolites block oxygen in the blood
from being used
Areas of the brain particularly
vulnerable to lack of oxygen include the cerebellum
and the parieto-occipital cortex, which play a large
role in co-ordination and movement along with memory.
Although the left and right hemispheres
are usually affected, damage can also occur in other
parts.
The brain stem and cerebellum are
responsible for maintaining vital body systems. A
stroke in this area can cause an array of difficulties
including unconsciousness, inability to speak, paralysis
and double vision.
3.
Encephalitis
Encephalitis means inflammation
of the brain and is caused by a virus. There are
two main types of encephalitis- acute viral cause
by a direct viral attack on the brain and post infectious,
an autoimmune condition whereby the body’s
immune system attacks the brain following a viral
infection elsewhere in the body. Sever viral encephalitis
can cause respiratory arrest, coma and death. In
the case of the brain it can cause mental impairments,
such as loss of memory, speech problems, lack of
muscle coordination, paralysis and hearing or vision
defects.
4.
Meningitis & Septicemia
There are two forms of this disease
that can lead to brain injury; viral and bacterial.
Many people recover but others are left with after
effects such as memory loss, learning difficulties,
lack of co-ordination, speech problems and seizures.
5.
Toxicity
The brain can be damaged by overuse
of substances such as alcohol, drugs and prescribed
drugs. Brain injury can be cause by these substances
as they have a toxic effect on the central nervous
system, change metabolism, heart functioning, blood
supply, interfere with absorption of brain nutrients,
cause dehydration and can lead to falls and accidents
that injure the brain.
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