what is stroke/cerebrovascular accident?
This
is a sudden death of some brain cells due to lack of oxygen when the blood flow
to the brain is impaired by blockage or rupture of an artery to the brain
.
Types
of Cerebrovascular Accident
• There are two types of
cerebral cardiovascular accidents/ stroke
o Ischemic
o Haemorrhagic
Ischemic
Stroke/CVA
• Ischemic stroke is the most
common type of stroke (~ 80%) usually due to a blocked
artery often by a blood clot
• Usually this type of stroke
results from clogged arteries, a condition called atherosclerosis
• Fat, cholesterol, and other
substances collect on the wall of the arteries forming a sticky
substance called plaque. Over time the
plaque builds up
This
often makes it hard for blood to flow properly which can cause the blood to
clot.
There
are two types of clots
o
A clot that stays in place in the brain
is called a cerebral thrombus
o
A clot that breaks loose and moves
through the blood to the brain is called a cerebral
embolism
• Transient ischemic attacks (TIAs) are
often an early warning sign of an impending
ischaemic
stroke
• They are caused by a brief interruption
of the blood supply to part of the brain
• Because the blood supply is restored
quickly, brain tissue may not die, as it does in a
stroke.
Hemorrhagic Stroke
• Rupture of an artery to the brain causing
blood to leak into the brain, this type of stroke most of the time its fatal.
Risk Factors
• Atherosclerosis
(narrowing or blockage of arteries by patchy deposits of fatty material in
the walls of arteries•
. High blood cholesterol levels
• High blood pressure
• Diabetes
• Smoking
• Family history of stroke
• Old age
• Too much alcohol
• Cocaine or amphetamines
consumption
• Abnormal heart rhythm (atria
fibrillation)
• Inflamed blood vessels
(vasculitis)
Causes
• An artery to the brain may be
blocked by a clot (thrombosis) which typically occurs in a
blood vessel that has previously been
narrowed due to atherosclerosis
• A blood clot can form in a
chamber of the heart when the heart beats irregularly, as in
atria fibrillation
• A cerebral hemorrhage
(bleeding in the brain), as from an aneurysm.
Clinical features of stroke
• Strokes
usually damage only one side of the brain
• Because
nerves in the brain cross over to the other side of the body sign appear on the
side
of the body opposite the damaged side of the brain
• Signs
and symptoms depend on the area of the brain affected
o
Change in alertness (consciousness)
o
Coma
o
Lethargy
o
Drowsiness
o
Stupor
• Difficulty
speaking or understanding others
• Difficulty
swallowing
• Difficulty
writing or reading
• Headache
o
Starts suddenly
o
Occurs when lying flat
o
Gets worse when changing positions or
when bending, strain, or cough
• Loss
of coordination
• Loss
of balance
• Movement
changes usually on only one side of the body
o
Difficulty moving any body part
o
Loss of fine motor skills
• Nausea
or vomiting
• Seizures
• Sensation
changes usually on only one side of the body
o
Decreased sensation
o
Numbness or tingling
• Sudden
onset of confusion
• Vision
changes
o
Decreased visionLoss of all or part of
vision
• Weakness or paralysis of one side of
the body
management of stroke
• Patients
clinically suspected of having CVA (history and examination) must be sent
hospital
for investigation and treatment.
• Take
blood pressure to rule out hypertension although sometimes blood pressure tends
to
normalize
after stroke.
• At
primary health care facilities, pre-referral management must be done before
patients
are
referred (i.e. ensuring airway is open, patient is breathing and circulation is
proper)
Investigations
• Diagnosis
is based on medical history and symptoms but imaging and blood tests are also
done
• The
blood sugar level is measured immediately because a low blood sugar level
(hypoglycemia)
can cause symptoms similar to those of stroke
• Other
tests at higher centers
o
Computed tomography (CT scan) or
Magnetic Resonance Imaging (MRI) of the brain
o
Complete blood count (CBC)
o
Electrocardiogram (ECG) to diagnose
underlying heart disorders
o
Echocardiogram if the stroke may have
been caused by a blood clot from the heart
o
Serum cholesterol
Treatment of ischemic stroke
• Definitive
management of patients with CVA must be done in the hospital.
• Treatments
designed to reverse or lessen the amount of tissue infarction fall within the
following
categories
o
Medical support
o
Thrombolysis
o
Anticoagulation (e.g. low molecular
heparin)
o
Antiplatelet agents (e.g. Aspirin)
• When
cerebral infarction occurs the immediate goal is to optimize cerebral perfusion
in
the
surrounding ischemic area.
• Attention
is also directed toward preventing the common complications of bedridden
patients
o
Infections
Pneumonia
Urinary tract
Skin
o
Deep venous thrombosis (DVT)
o
Pulmonary embolism
• If
treatment can be started within 3 hours of the first symptom then thrombolytic
therapy
(‘clot
breaking drug’) may be considered as an option
• Low
doses of intravenous heparin is sometimes an option
• Supportive
measures may be considered as an option• Blood pressure is cautiously
controlled. Lowering blood pressure too much may cause
another stroke to occur
Hemorrhagic
Stroke
• Supportive measures only
• All blood thinning medications
will make a stroke worse and therefore need to be avoided
• Correct any bleeding problems
• Blood pressure is controlled
very cautiously
• Treatment of blood pressure
that is too high or too low may be necessary
o Lowering elevated blood pressure into
the normal range is no longer recommended
during the first few days following a
stroke (current recommendation is to have BP
between 140-160 systolic in setting of
acute stroke)
o If the blood pressure is low, raising
it is advisable using intravenous fluids
• Pain killers may be given to
control severe headache but avoid respiratory depression
• The blood sugar (glucose) in
diabetics is often quite high after a stroke
• Controlling the glucose level
may minimize the size of a stroke
• Oxygen is given as needed
Rehabilitation
• The goal of long-term treatment
is to help the patient recover as much function as
possible and prevent future strokes
• Depending on the symptoms
rehabilitation may include
o Occupational therapy
o Physical therapy
o Speech therapy
Prevention of stroke.
General Principles
• A
number of medical and surgical interventions as well as life-style
modifications are
available
for preventing stroke.
• Some
of these can be widely applied because of their low cost and minimal risk.
• Others
are expensive and carry substantial risk but may be valuable for selected
high-risk
patients.
• One
of the most important interventions to prevent stroke is to identify hypertension early and
initiate
proper treatment.
• If
the patient has atrial fibrillation, warfarin is recommended, secondary option
aspirin.
• Cholesterol
levels should be brought to normal level.
• Diabetes
mellitus should be controlled.
• Alcohol
consumption should be limited.
• Exercising
regularly and if overweight, losing weight helps people control high blood
pressure,
diabetes, and high cholesterol levels.
• Having
regular checkups enables a doctor to identify risk factors for stroke so that
they
can
be managed quickly.
• Stop
smoking - this is probably the second most important intervention after
hypertension control
• Low
dose aspirin 75 mg daily should be instituted in those at high risk for stroke
with
risk
factors (e.g. persons with previous stroke or TIA, diabetics, those with known
cardiac
disease, or atherosclerosis). Do not use if contraindications for aspirin
exist.
