CEREBROVASCULAR ACCIDENT
cerebellum
A region of the brain at the back of the
skull, behind the
brainstem
. T h e
cerebel-
lum is concerned prim arily with the
maintenance of posture and balance
and the coordination of movement.
STRUCTURE
The cerebellum is linked to the
brain-
stem
by thick nerve tracts. It consists of
two hemispheres. From the inner side
of each hemisphere arise three nerve
fibre stalks, w hich link with different
parts of the brainstem and carry signals
between the cerebellum and the rest of
the brain. Nerve fibres from the stalks
fan out towards the deep folds of the
cortex
(outer part)
of each cerebellar
hemisphere, w hich consists of layers of
what is often referred to as
grey matter
(interconnected nerve cells).
FUNCTION
Information about the body’s posture
and the state of contraction or relax-
ation in its muscles is conveyed from
muscle tendons and the labyrinth in
the inner ear via the brainstem to the
cerebellum. Working
with
the
basal
ganglia
(nerve cell clusters deep w ithin
the brain), the cerebellum uses this
data to fine tune messages sent to mus-
cles
from
the motor
cortex in the
cerebrum
(the main mass of the brain).
DISORDERS
Disease or damage to the cerebellum
may result in
cerebral ataxia
,
w hich is
characterized by jerky, staggering gait,
slurred speech, and other uncoordin-
ated movements of the body.
Alcohol
intoxication
impairs cerebellar function
and may produce sim ilar symptoms.
cerebral haemorrhage
Bleeding that occurs w ithin the brain
due to a ruptured blood vessel (see
intracerebral haemorrhage; stroke
) .
cerebral malaria
A
potentially
fatal
complication
of
malaria
(a disease transmitted by mos-
quitoes)
that
affects
the
brain
and
causes loss of consciousness.
cerebral oedema
An abnormal accumulation of fluid in
the
brain
.
The resulting compression of
brain tissues may cause symptoms such
as headache and visual disturbances.
There are various causes for cerebral
oedema, including injury,
anoxia
(lack
of oxygen), and poisoning.
cerebral palsy
A disorder of posture and movement
that results from damage to the devel-
oping brain before, during, or just after
birth, or in early childhood. Cerebral
palsy is nonprogressive. The disorder
varies in severity from slight clum si-
ness of hand movement and gait to
complete immobility.
CAUSES
In most cases, damage occurs before or
at birth, sometimes as a result of cere-
bral
hypoxia
(an inadequate supply of
oxygen to the brain). More rarely, the
cause
is
a
maternal
infection
that
spreads to the baby in the uterus.
In rare cases, cerebral palsy is caused
by
kernicterus
,
w hich results from an
excess of bile pigment in babies with
haemolytic disease of the newborn
.
Possible
causes after birth include
encephalitis
(inflammation
of the
brain
tissue),
meningitis
(inflammation of the protec-
tive membranes covering the brain),
head injury
,
or
intracerebral haemorrhage
(bleeding w ithin the brain).
SYMPTOMS
Cerebral palsy may not be recognized
until well into the baby’s first year. In i-
tially, the infant may have hypotonic
(floppy) muscles, be difficult to feed,
and show delay in sitting up without
support. An affected child may go on
to develop
spastic paralysis
(abnormal
muscle stiffness),
athetosis
(involuntary
writhing movements), or
ataxia
(loss of
coordination and balance). Other ner-
vous system disorders, such as hearing
defects or epileptic seizures, may be
present. About
70
per cent of children
have mental impairment, but the rest
are of normal or high intelligence.
DIAGNOSIS AND TREATMENT
If the condition is suspected from the
symptoms and from neurological and
developmental
assessments,
imaging
tests such as
CTscanning
and
MRI
may be
performed to identify brain damage.
Although there is no cure for cere-
bral palsy, much can be done to help
affected children. A team of profession-
als
working
with
the
family
can
maximize the child’s ability to func-
tion.
Physiotherapy
can help a child to
develop muscular control and maintain
balance.
Speech therapy
may
improve
speech and communication.
cerebral thrombosis
The formation of a
thrombus
(blood
clot) in an artery w ithin the brain. The
clot may block the artery, cutting off
the supply of blood, nutrients, and
oxygen to the region of the brain tissue
supplied by the artery. This problem
may result in a
stroke
.
cerebrospinal fluid
A clear,
watery fluid that
circulates
between the ventricles (cavities) within
the
brain
,
the central canal in the
spinal
cord
,
and the space between the brain
and spinal cord and their protective
coverings, the
meninges
.
Cerebrospinal
fluid functions as a shock-absorber,
helping to prevent or reduce damage to
the brain and spinal cord after a blow
to the head or back. It contains glucose,
proteins, salts, and white blood cells.
Examination of the fluid, samples of
w hich are usually obtained by
lumbar
puncture
,
is used in the diagnosis of
many conditions affecting the brain
and spinal cord, including
meningitis
and
subarachnoid haemorrhage
.
Accumulation of cerebrospinal fluid
w ithin the skull during the develop-
ment of the fetus, or in infancy, may
cause the skull to become enlarged (a
condition known as
hydrocephalus
).
cerebrovascular accident
Any sudden rupture or blockage of a
blood vessel in the brain. The problem
causes serious bleeding and/or local
C
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