A stroke occurs when blood supply to the brain is interrupted, depriving brain cells of oxygen. Strokes can be either ischemic (88%), caused by clot or embolism blocking an artery, or hemorrhagic (12%), caused by bleeding within the brain. Diagnosis involves physical exam, blood tests, CT/MRI scans of the brain, and tests of the heart and arteries. Ischemic strokes result from plaque buildup in arteries leading to clot formation, while hemorrhagic strokes damage brain tissue through blood toxicity. Prompt treatment is needed to minimize brain injury from loss of oxygen and blood toxicity.

1. STROKE
By Dr.M.A.Ansari

2. DEFINITION
• A stroke occurs when the blood supply to part of your brain is
interrupted or reduced, depriving brain tissue of oxygen and nutrients.
Within minutes, brain cells begin to die

3. ETIOLOGY AND CLASSIFICATION
• Stroke can be either ischemic or hemorrhagic (88%
and 12%, respectively.
• HEMORRHAGIC STROKES include subarachnoid
hemorrhage, intracerebral hemorrhage, and subdural
hematomas.
• Subarachnoid hemorrhage occurs when blood enters
the subarachnoid space (where cerebrospinal fluid is
housed) owing to either trauma, rupture of an
intracranial aneurysm.
• intracerebral hemorrhage occurs when a blood vessel
ruptures within the brain parenchyma itself, resulting
in the formation of a hematoma.

4. •Subdural hematomas refer to collections of blood
below the dura (covering of the brain), and they are
caused most often by trauma.
•HEMATOMA-defined as a collection of blood outside
of blood vessels. Most commonly, hematomas are
caused by an injury to the wall of a blood vessel,
prompting blood to seep out of the blood vessel into the
surrounding tissues.
•HEAMORRHAGE-A hematoma usually describes
bleeding which has more or less clotted, whereas a
hemorrhage signifies active, ongoing bleeding.

5. • ISCHEMIC STROKES are caused either by local
thrombus formation or by embolic phenomenon, resulting
in occlusion of a cerebral artery. Atherosclerosis,
particularly of the cerebral vasculature, is a causative factor
in most cases of ischemic stroke
• Atherosclerosis- a condition where the arteries become
narrowed and hardened due to a build up of plaque around
the artery wall.
• Emboli can arise either from intra- or extracranial arteries
• Cardiogenic embolism is presumed to have occurred if the
patient has concomitant atrial fibrillation, valvular heart
disease, or any other condition of the heart that can lead to
clot formation.

7. RISK FACTORS
• Risk factors for stroke can be subdivided into
1. nonmodifiable
2. modifiable, and
3. potentially modifiable
• The nonmodifiable risk factors are age, race, sex, low birth weight, and family
history.
• An individual’s risk of having a stroke increases substantially as he or she
ages, with a doubling of risk for each decade older than 55 years of age.
• The most common modifiable, well-documented risk factors for stroke include
hypertension, cigarette smoking, diabetes, atrial fibrillation, and dyslipidemia

9. SYMPTOMS
• Trouble with speaking and understanding. You may experience confusion.
You may slur your words or have difficulty understanding speech.
• Paralysis or numbness of the face, arm or leg. You may develop sudden
numbness, weakness or paralysis in your face, arm or leg. This often happens
just on one side of your body. Try to raise both your arms over your head at
the same time. If one arm begins to fall, you may be having a stroke. Also,
one side of your mouth may droop when you try to smile.
• Trouble with seeing in one or both eyes. You may suddenly have blurred or
blackened vision in one or both eyes, or you may see double.
• Headache. A sudden, severe headache, which may be accompanied by
vomiting, dizziness or altered consciousness, may indicate you're having a
stroke.
• Trouble with walking. You may stumble or experience sudden dizziness, loss
of balance or loss of coordination.

10. • Seek immediate medical attention if you notice any
signs or symptoms of a stroke, even if they seem to
fluctuate or disappear. Think "FAST" and do the
following:
• Face. Ask the person to smile. Does one side of the
face droop?
• Arms. Ask the person to raise both arms. Does one
arm drift downward? Or is one arm unable to rise up?
• Speech. Ask the person to repeat a simple phrase. Is
his or her speech slurred or strange?
• Time. If you observe any of these signs, call 911
immediately.

11. DIAGNOSIS
• PHYSICAL EXAMINATION.
1. Your doctor will want to know what medications you take and whether you have
experienced any head injuries. You'll be asked about your personal and family
history of heart disease, transient ischemic attack and stroke.
2. Your doctor will check your blood pressure and use a stethoscope to listen to your
heart and to listen for a whooshing sound (bruit) over your neck (carotid) arteries,
which may indicate atherosclerosis. Your doctor may also use an ophthalmoscope
to check for signs of tiny cholesterol crystals or clots in the blood vessels at the
back of your eyes.
• BLOOD TESTS. blood tests, tell your care team how fast your blood clots, whether
your blood sugar is abnormally high or low, whether critical blood chemicals are out
of balance, or whether you may have an infection.
• COMPUTERIZED TOMOGRAPHY (CT) SCAN. A CT scan uses a series of X-
rays to create a detailed image of your brain. A CT scan can show a hemorrhage,
tumor, stroke and other conditions. Doctors may inject a dye into your bloodstream
to view your blood vessels in your neck and brain in greater detail (computerized
tomography angiography).

12. • MAGNETIC RESONANCE IMAGING (MRI). An MRI uses powerful radio waves and
magnets to create a detailed view of your brain. An MRI can detect brain tissue damaged by
an ischemic stroke and brain hemorrhages. Your doctor may inject a dye into a blood
vessel to view the arteries and veins and highlight blood flow (magnetic resonance
angiography, or magnetic resonance venography).
• CAROTID ULTRASOUND. In this test, sound waves create detailed images of the inside
of the carotid arteries in your neck. This test shows buildup of fatty deposits (plaques)
and blood flow in your carotid arteries.
• CEREBRAL ANGIOGRAM. In this test, your doctor inserts a thin, flexible tube (catheter)
through a small incision, usually in your groin, and guides it through your major arteries and
into your carotid or vertebral artery. Then your doctor injects a dye into your blood vessels to
make them visible under X-ray imaging. This procedure gives a detailed view of arteries in
your brain and neck.
• ECHOCARDIOGRAM. An echocardiogram uses sound waves to create detailed images of
your heart. An echocardiogram can find a source of clots in your heart that may have
traveled from your heart to your brain and caused your stroke.
• TRANSESOPHAGEAL ECHOCARDIOGRAM. In this test, your doctor inserts a flexible
tube with a small device (transducer) attached into your throat and down into the tube that
connects the back of your mouth to your stomach (esophagus). Because your esophagus is
directly behind your heart, a transesophageal echocardiogram can create clear, detailed
ultrasound images of your heart and any blood clots.

13. CT SCAN OF BRAIN TISSUE
DAMAGED BY STROKE
CEREBRAL ANGIOGRAM
A CEREBRAL ANGIOGRAM SHOWING A CAROTID
ANEURYSM ASSOCIATED WITH STROKE.

14. PATHOPHYSIOLOGY
ISCHEMIC STROKE
• In carotid atherosclerosis, progressive accumulation of lipids and
inflammatory cells in the intima of the affected arteries, combined with
hypertrophy of arterial smooth muscle cells, results in plaque formation.
• Eventually, sheer stress may result in plaque rupture, collagen exposure,
platelet aggregation, and clot formation.
• The clot can remain in the vessel, causing local occlusion, or travel distally as
an embolism, eventually lodging downstream in a cerebral vessel. Thus
leading to blockage of blood supply to brain in turn causing STROKE

15. •Normal cerebral blood flow averages 50 mL/100 g per
minute, and this is maintained over a wide range of blood
pressures by a process called cerebral autoregulation.
•Cerebral blood vessels dilate and constrict in response to
changes in blood pressure, but this process can be impaired
by atherosclerosis and acute injury, such as stroke.
• When local cerebral blood flow decreases below 20
mL/100 g per minute, ischemia ensues, and when further
reductions below 12 mL/100 g per minute persist,
irreversible damage to the brain occurs, and this is called
infarction.

16. HEMORRHAGIC STROKE
•The pathophysiology of hemorrhagic stroke is not as
well studied as that of ischemic stroke.
•However, it is known that the presence of blood in the
brain parenchyma causes damage to the surrounding
tissue and the neurotoxicity of the blood components
and their degradation products may be a cause.

17. ALL THE VERY
BEST TO MY
DEAR STUDENTS