PTH 623 - Week 1 Material

What is a stroke?

A sudden loss of neurological functions

What is a stroke caused by?

Interruption of blood flow to the brain tissue

What causes interruption of blood flow?

Can either occur by blockage or leakage

What type of stroke is a blockage of blood flow?

Ischemic

What type of stroke is leakage of blood due to a vessel rupture?

Hemorrhagic

What does thrombosis mean?

Growing clot

What does an embolism mean?

Travelling clot

What does stenosis mean?

Narrowing artery

Give examples of some neurological functions

Movement planning and execution, vital functions, reflexes, autonomic and sympathetic functions, sensory information and perception, cognition/decision-making and emotions, motor control, sleep and arousal, swallowing, etc

What is a transient ischemic attack (TIA)?

A “mini-stroke” because neurological symptoms last for less than 24 hours

How is a stroke different from a TIA?

A stroke has permanent symptoms that last at least 3 weeks after the incident

What does FAST mean?

Face, arms, speed, and time

What does BE FAST mean?

Balance, eyes, face, arms, speed, and time

Who is most affected by strokes?

Those older than 65 years; typically men more than women

What is a thrombotic ischemic stroke?

A clot grows against inside wall of an artery producing slowly worsening deficits

What typically causes thrombotic ischemic strokes?

Atherosclerotic vascular diseases where platelet activation is stimulated. The blood clots because it gets trapped by the plaque

What is plaque?

Deposits of cholesterol, fats, and cellular waste

What is a clot?

A fibrin mesh that can create scars

Where do plaques typically occur?

Bifurcations/branching of vessels

What is an embolic ischemic stroke?

A travelling clot that lodges in a brain artery of smaller diameter, abruptly blocking the flow, and produces sudden deficits

What are most emboli caused by?

Blood turbulence from arrhythmically beating hearts or a malfunctioning valve

What arteries are most frequently involved with embolic ischemic strokes?

Vertebrobasilar and middle cerebral arteries

What are hypo-perfusion ischemic strokes?

Caused by low systemic perfusion blood pressure due to conditions such as MI, arterial aneurysm leak, significant blood loss, acute dehydration, or overactive hypertensives

Where is the most common site for hypo-perfusion ischemic strokes?

Bilateral watershed areas or between the middle cerebral and anterior cerebral arteries

What increases the risk of hemorrhagic strokes?

Hypertension

What is a hemorrhagic stroke?

Blood leak from non-traumatic rupture of arterial wall aneurysm

What is perception?

Putting meaning to sensations

What is apraxia?

Not knowing what an object is

What is clotting caused by?

Producing fibrin

What is the function of thrombolytics?

Dissolve existing blood clots

What is a side effect of Lipitor?

Muscle weakness

Are more strokes ischemic or hemorrhagic?

Ischemic

Approximately, what percentage of strokes are ischemic?

87%

What can produce an ischemic stroke?

Thrombosis, embolism, or stenosis

A patient develops neurological symptoms that completely resolve within several hours. How would you describe this?

TIA

What is identified as the most important risk factor for a stroke?

Hypertension

A patient has atherosclerotic plaque within an artery. Platelets become activated and trapped around the plaque, eventually producing a fibrin mesh that enlarges along the arterial wall. Which type of stroke mechanism is this?

Thrombotic ischemic stroke

Do embolic or thrombotic strokes cause symptoms faster?

Embolic

A patient with atrial fibrillation develops sudden neurological deficits. Which mechanism is this?

Cardiogenic embolism

Which arteries are identified as being frequently involved in embolic ischemic strokes?

Vertebrobasilar and middle cerebral arteries

A patient experiences a severe systemic decrease in blood pressure following significant blood loss. Which type of ischemic stroke is most associated with this mechanism?

Hypoperfusion

What can contribute to embolic material?

Blood clot, air bubble, fat bubble, or tumor cells

A growing clot that develops against the inside wall of an artery is called?

Thrombus

The area of irreversible cell damage at the center of an ischemic lesion is called?

Infarct/core

The metabolically inactive but potentially salvageable tissue surrounding the infarct core is called?

Penumbra

Temporary inhibition of function in brain regions distant from the ischemic core is called?

Diaschisis

What is the role of coagulation factors?

Form a clot by producing fibrin

What is the role of platelets?

Form a clot by aggregation near an injury

What activate coagulation factors?

Endothelial or tissue damage

What is the intrinsic pathway for clotting?

Injury inside the blood vessel

What is an extrinsic pathway for clotting?

Injury outside the blood vessel (in tissues)

What is platelet activation caused by?

Arterial wall (endothelial) injury

What is a hyper-coagulable state?

More likely to form clot and have an ischemic CVA, MI, or DVT

What causes a hyper-coagulable state?

High platelets or easily triggered coagulation factors

What is a hypo-coagulable state?

Risk of bleeding, causing hemorrhagic CVA or other hematomas

What causes a hypo-coagulable state?

Low platelets, or poorly functioning platelets, and coagulation factors disorders, or drugs

What causes turbulence?

Reducing lumen of the arteries or roughening of the arterial walls from deposits of excess cholesterol and lipids

What can increase the risk of atherosclerosis and the coagulation cascade?

High concentration of inflammatory proteins

What is ecchymosis?

Purple skin splotches

If a patient cannot flex at the hip and reports pain with the effort after being started on clot prevention/dissolving drugs, what should you be worried about?

Iliac and psoas muscle sheaths being vulnerable to hematomas

What should you look out for with patients who are on chemotherapy?

Massive drops in platelet counts, making them susceptible to bleeding

What is a risky platelet count?

Below 50K

What could be done if hypercoagulability is hard to manage?

A clot filter may be implanted into the inferior vena cava to prevent the emboli to reach the brain or heart’s arteries

What is the purpose of an anticoagulant?

Inhibits production of thrombin and factor Xa (enzyme producing thrombin)

Anticoagulant examples?

Coumarin, Dalteparin (Fragmin), and Enoxaparin (Lovenox)

What are anticoagulants used for?

Acute treatment of venous thrombosis and thromboembolism

How is Warfain (Coumadin) administered?

Orally

How long does it take for Warfarin to work?

Several days

What is the antidote for Warfarin?

Vitamin K

How can Fondaparinux (Arixtra) be administered?

Subcutaneous injection

Antidote to Apixaban (Eliquis) and Rivaroxaban (Xarelto)?

Recombinant factor Xa (drugs bind to that instead of patient’s factor Xa)

What type of medication is aspirin?

Antiplatelet

How does aspirin work?

Inhibits the cyclooxygenase enzyme that initiates the synthesis of lipid like hormone (prostaglandins and thromboxanes)

What does Clopidogrel (Plavix) do?

Inhibit the adenosine diphosphate (ADP) receptor on the platelet membrane and reduce platelet aggregation

What is Clopidogrel (Plavix) used for?

Thrombosis in patients at risk for myocardial infarction or ischemic stroke and to prevent infarction following percutaneous coronary angioplasty, placement of coronary artery stent, and other surgical procedures

What type of medication is tissue plasminogen activator (t-PA)?

Fibrinolytic agent

What does a t-PA do?

Breakdowns and causes the dissolution of clots that have already been formed

What type of medication is Atorvastatin (Lipitor)?

Hyperlipidemia drug (statin)

How does Atorvastatin work?

Inhibits 3-hydroxy-3methylglutaryl enzyme A reductase and catalyzes one of the early steps of cholesterol synthesis

What is Atorvastatin (Lipitor) used for?

Decrease cholesterol production in liver cells and prevent and treat hyperlipidemia