Stroke is the 5th leading cause of death in the US. There are three main types of stroke: ischemic, hemorrhagic, and transient ischemic attacks (TIAs). Ischemic strokes, which account for 85% of cases, occur when a blood clot blocks an artery supplying blood to the brain. Hemorrhagic strokes occur when a brain artery ruptures due to conditions like hypertension. TIAs are temporary and cause no permanent damage but indicate risk for future strokes. Symptoms of stroke appear suddenly and include face drooping, arm weakness, speech difficulties, and severe headache. Diagnostic tests help determine the type and location of stroke. Lifestyle changes and medical treatment can help prevent strokes.

2. ⦁ Stroke is the 5th leading cause of death in the US, with
one person dying every 4 minutes . For black people,
stroke is the 3rd leading cause of death.It is the second
leading cause of death in the world.
⦁ Approximately 800,000 people have a stroke each year;
about one every 40 seconds.
⦁ Strokes occur due to problems with the blood supply to
the brain: either the blood supply is blocked or a blood
vessel within the brain ruptures, causing brain tissue
to die.
⦁ A stroke is a medical emergency, and treatment must
be sought as quickly as possible.
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3. ⦁ A stroke is defined as the clinical syndrome of rapid
onset of cerebral deficit lasting more than 24 hours
or leading to death with no apparent cause other
than a vascular one.
⦁ A stroke is a rapid loss of brain function due to the
disturbance in the blood supply to brain. A stroke
happens when blood flow to a part of the brain
stops and it is sometimes called a “brain attack”
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6. There are three main kinds of stroke:
⦁ Ischemic strokes
⦁ Hemorrhagic strokes
⦁ Transient ischemic attacks (TIAs), also referred to as
mini-strokes
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11.  ISCHEMIC STROKE
⦁ Ischemic stroke is the most common form of stroke,
accounting for around 85% of strokes.
⦁ This type of stroke is caused by blockages or
narrowing of the arteries that provide blood to the
brain, resulting in ischemia - severely reduced
blood flow.
⦁ These blockages are often caused by blood clots.
Clots can be caused by fatty deposits within the
arteries called plaque.
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12.  HEMORRHAGIC STROKE:
⦁ Hemorrhagic stroke are caused by arteries in the
brain either leaking blood or bursting open.
⦁ The ruptures can be caused by conditions such as
hypertension, trauma, blood-thinning medications
and aneurysms (weaknesses in blood vessel walls).
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13. ⦁ Intra cerebral hemorrhage is the most common
type of hemorrhagic stroke and occurs when brain
tissue is flooded with blood after an artery in the
brain bursts.
⦁ Subarachnoid hemorrhage is the second type of
hemorrhagic stroke and is less common. In this type
of stroke, bleeding occurs in the subarachnoid space
- the area between the brain and the thin tissues
that cover it.
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14.  TRANSCIENT ISCHEMICATTACK (TIA)
⦁ TIAs are different from the aforementioned kinds of
stroke because the flow of blood to the brain is only
briefly interrupted. TIAs are similar to ischemic
strokes in that they are often caused by blood clots
or other debris.
⦁ TIAs should be regarded as medical emergencies.
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15. ⦁ They serve as warning signs for future strokes and
indicate that there is a partially blocked artery or
clot source in the heart.
⦁ According to the Centers for Disease Control and
Prevention (CDC), over a third of people who
experience a TIA go on to have a major stroke
within a year if they have not received any
treatment. Between 10-15% will have a major
stroke within 3 months of a TIA.
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16. Strokes occur quickly and, as such, symptoms of stroke
often appear suddenly without warning.
The main symptoms of stroke are as follows:
⦁ Confusion, including trouble with speaking and
understanding
⦁ Headache, possibly with altered consciousness or
vomiting
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17. ⦁ Numbness of the face, arm or leg, particularly on
one side of the body
⦁ Trouble with seeing, in one or both eyes
⦁ Trouble with walking, including dizziness and lack
of co-ordination.
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18. In addition to the persistence of the problems listed
previously, patients may also experience the following:
⦁ Bladder or bowel control problems
⦁ Depression
⦁ Pain in the hands and feet that gets worse with
movement and temperature changes
⦁ Paralysis or weakness on one or both sides of the
body
⦁ Trouble controlling or expressing emotions.
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19. PATHOPHYSIOLOGY: ISCHAEMIC STROKE
 The pathophysiology of stroke is complex and involves
numerous processes, including
• Energy failure
• Loss of cellular ion homeostasis
• Acidosis
• Increased intracellular calcium levels
• Excitotoxicity
• Free radical-mediated toxicity
• Generation of arachidonic acid products
• Cytokine-mediated cytotoxicity
• Activation of glial cells, and infiltration of leukocytes
• Disruption of the blood-brain barrier (BBB)

20. • Blood supply to the brain is autoregulated
• Blood flow
• if zero leads to death of brain tissue within 4-10min
• 16-18ml/100g tissue/min infarction within an hour
• Ischemia leads to the development of an ischemic
core and an ischemic penumbra

21. ISCHAEMIC PENUMBRA

22. GLUTAMATE EXCITOTOXICITY
 Ischemia-induced neuronal damage is mediated by
excessive accumulation of excitatory amino acids,
leading to a toxic increase in intracellular calcium.
 This increase in intracellular calcium activates
multiple signalling pathways,
 which ultimately leads to cell death.
 The reduction or termination of cerebral blood
flow, energy-dependent cellular pumps fail due to
a fall in glucose-dependent ATP generation.
 This results in cellular swelling through osmosis and
cellular depolarization.

23.  Calcium ions (Ca2+) enter the cell through the
voltage-dependent and ligand-gated ion channels,
resulting in the activation of several proteases,
kinases, lipases, and endonucleases
 Triggering the intrinsic apoptotic pathway and thus
ending in cell death by Glutamate, which is the major
excitatory neurotransmitter in the brain, accumulates in
the extracellular space following ischemia and activates
its receptors.

24.  Oxidative stress and apoptosis are closely linked
phenomena in the pathophysiology of ischemic stroke.
 Free radicals like superoxide anion radical, hydroxyl
radical and nitric oxide (NO) produced by mitochondria
are involved in stroke-induced brain injury.
 Free radicals can react with DNA, proteins and lipids,
causing varying degrees of damage and dysfunction.
 Oxygen free radicals can also be generated by activated
microglia and infiltrating peripheral leukocytes via the
NADPH oxidase system following reperfusion of ischemic
tissue.
 This oxidation causes further tissue damage and is thought
to be an important trigger molecule for apoptosis after
ischemic stroke.
OXIDATIVE STRESS

25. LIPID PEROXIDATION
 Lipid peroxidation plays a prominent role in the
pathogenesis of stroke.
 The mechanism, whereby membrane lipid peroxidation
induces Neuronal apoptosis involves the generation of
an aldehyde called 4- hydroxynonenal (4-HNE),
which covalently modifies membrane transporters such
as the Na+ /K+ ATPase, glucose transporters and
glutamate transporters, thereby impairing their
function

26. INFLAMMATION AND LEUCOCYTE
INFILTRATION
 Inflammation in stroke is characterized by the
accumulation of leukocytes and activation of
resident microglial cells.
 Inflammatory cells can contribute to stroke pathology
through two basic mechanisms.
 They form aggregates in the venules after reperfusion
or enter infarcted tissue and exacerbate cell death
through the production of free radicals and cytokines.
 Cell adhesion molecules such as selectins, integrins, and
ICAMs permit endothelial-inflammatory cell
interactions.

27. PATHOPHYSIOLOGY: HAEMORRHAGIC
STROKE
 Explosive entry of blood into the brain parenchyma
structurally disrupts neurons
 Immediate cessation of neuronal function
 Expanding hemorrhage can act as a mass lesion and
cause further progression of neurological deficits
 Large hemorrhages can cause transtentorial coning
(movement of brain tissue from one intracranial
compartment to other) and rapid death

29.  Strokes happen fast and will often occur before an
individual can be seen by a doctor for a proper diagnosis.
 The acronym F.A.S.T. is a way to remember the signs
of stroke, and can help identify the onset of stroke
more quickly:
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31. ⦁ Face drooping: if the person tries to smile does one
side of the face droop?
⦁ Arm weakness: if the person tries to raise both their
arms does one arm drift downward?
⦁ Speech difficulty: if the person tries to repeat a
simple phrase is their speech slurred or strange?
⦁ Time to call 911( In USA) and 108 ( In India): if any
of these signs are observed, contact the emergency
services.
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32. There are several different types of diagnostic tests that
doctors can use in order to determine which type of
stroke has occurred:
⦁ Physical examination: a doctor will ask about the
patient's symptoms and medical history. They may
check blood pressure, listen to the carotid arteries in
the neck and examine the blood vessels at the back of
the eyes, all to check for indications of clotting
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33. ⦁ Blood tests: a doctor may perform blood tests in
order to find out how quickly the patient's blood
clots, the levels of particular substances (including
clotting factors) in the blood, and whether or not the
patient has an infection
⦁ CT scan: a series of X-rays that can show
haemorrhages, strokes, tumours and other conditions
within the brain
⦁ MRI scan: radio waves and magnets create an image
of the brain to detect damaged brain tissue
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34. ⦁ Carotid ultrasound: an ultrasound scan to check the
blood flow of the carotid arteries and to see if there is
any plaque present
⦁ Cerebral angiogram: dyes are injected into the
brain's blood vessels to make them visible under X-
ray, in order to give a detailed view of the brain and
neck arteries
⦁ Echocardiogram: a detailed image of the heart is
created to check for any sources of clots that could
have travelled to the brain to cause a stroke.
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35. PREVENTION
•Eating a healthy diet.
•Maintaining a healthy weight.
•Exercise regularly.
•Do not smoke.
•Avoiding alcohol or drink moderately.
•Keeping blood pressure under control.
•Managing diabetes.
•Treating obstructive sleep apnea (if present).

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• Alteplase (tPA, tissue plasminogen activator) initiated
within 4.5 hours of symptom onset reduces disability
from ischemic stroke.
• Aspirin 160 to 325 mg/day started between 24 and 48
hours after completion of alteplase also reduces long-
term death and disability.
• Secondary prevention of ischemic stroke: Use
antiplatelet therapy in non-cardioembolic stroke.
• Aspirin, clopidogrel, and extended-release
dipyridamole plus aspirin are all first-line agents.
• Cilostazol is also a first-line agent, but its use has been
limited by a lack of data

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• Oral anticoagulation is recommended for atrial fibrillation and a
presumed cardiac source of embolism.
• A vitamin K antagonist (warfarin) is the first line, but other oral
anticoagulants (eg, dabigatran) may be recommended for some
patients.
• Statins reduce the risk of stroke by approximately 30% in patients
with coronary artery disease and elevated plasma lipids.
• Low-molecular-weight heparin or low-dose subcutaneous
unfractionated heparin (5000 units three times daily) is
recommended for the prevention of deep vein thrombosis in
hospitalized patients with decreased mobility due to stroke and
should be used in all but the most minor strokes.
• The calcium channel blocker nimodipine 60 mg every 4 hours
for 21 days, along with maintenance of intravascular volume with
pressor therapy, is recommended to reduce the incidence and
severity of neurologic deficits resulting from delayed ischemia.

38. Questions
1. What is Stroke? Explain the causes of stroke.

39. Thank You