A stroke occurs when the blood supply to part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. There are three main types of stroke: ischemic, caused by a blood clot blocking a vessel; hemorrhagic, caused by a burst blood vessel; and transient ischemic attacks or mini-strokes, which are temporary clots. Risk factors for stroke include high blood pressure, heart disease, smoking, and obesity. Symptoms depend on the affected brain region but may include weakness, vision issues, and impaired speech or movement. Treatment focuses on rapidly restoring blood flow through clot-busting drugs or surgery.
1. STROKE
It is also called as cerebral Infarction[Infarction is tissue death (necrosis) due to
inadequate blood supply to the affected area. It may be caused by artery
blockages, rupture, mechanical compression, or vasoconstriction.
2. DEFINITION
It is a stage where the blood flow to brain stops and the brain cell begin to
die due to deficiency of oxygen.
The affect on the brain due to the stroke depends upon which area of the
brain the stroke has occurred and how much damage is taken place in that
area.
Small stroke may have minor problems like temporary weakness of the arm or
leg.
Larger stroke may permanently paralyze one side of the person’s body and
he/she may also loose his/her ability to speak.
3. DIFFERENT TYPES OF STROKE
1. Ischemic Stroke: It is caused by a blood clot that blocks or plugs a blood
vessel in the brain.
2. Hemorrhagic Stroke : It occurs when blood vessels breaks and bleeds into
the brain.
3. Mini Stroke: They are called as Transient Ischemic Attacks which occur
when blood supply to the brain is briefly interrupted.
4. ETIOLOGY OF STROKES
Lodging of fatty material (atheroma) and calcium in the small blood
vessels supply to the brain.
The hypertension, heart disease, coronary atherosclerosis,
polycythemia etc. also increase risk of stroke.
The lodging of a clot, in cerebral arteries called cerebral embolism.
Severe infection also narrows the blood vessels.
Drug induced (e.g. Cocaine, amphetamine) narrowing of cerebral
arteries.
Sustained loss of blood pressure.
Massive loss of blood during surgery.
Head Injury.
5. PATHOPHYSIOLOGY OF STROKE
The brain requires a constant supply of oxygen since there is no
reserve of oxygen.
When the blood flow to the brain is stopped the brain cell may get
damage and die due to obstruction in supply of oxygen that is also
called as cerebral ischemia.
This leads to a neurological deficit which can result in the coma,
hemiplegia, speech impairment , sensory impairment.
In the hemorrhagic strokes arteries in the brain either leak blood or
burst open.
The leaked blood put pressure on brain cell and damage them.
Blood vessels can burst and spill blood within the brain or near the
surfaces of the brain , sending blood into the space between the brain
and skull.
6. CLINICAL SYMPTOMS
Weakness
Abnormal sensation
Blindness
Double vision
Loss of memory
Loss of muscle control
* If not treated or not cured severe strokes can lead in death, coma and
paralysis.
7. TREATMENT
Tissue plasminogen activator (tPA) is given via intravenous therapy
(IV) and works by dissolving the blood clot and improving blood flow
to the part of the brain deprived of the blood flow.
It should be given within 3 hours and upto 4.5 hours from the time the
symptoms started.
Mechanical devices are also used to break the blood clots when the
drugs are ruled out.
