CAUSES, TREATMENT AND PREVENTION OF STROKE.

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.