What is a stroke?
The three primary types of strokes are:
- Hemorrhagic stroke: Caused by blood vessel rupture resulting in damage to brain tissue.
- Ischemic stroke: Caused by blood clot blocking a blood vessel and cutting off blood supply to a part of the brain.
- Transient ischemic attack (TIAs): Brief period of reduced blood supply that usually lasts just a few minutes and resolves on its own. TIAs are often a precursor for ischemic strokes.
What is thrombolytic therapy for stroke?
Thrombolytic therapy is a treatment to break up the blood clot in the brain’s blood vessel which caused the ischemic stroke. An enzyme known as tissue plasminogen activator (tPA) is administered to dissolve the blood clot and restore normal blood flow to the brain.
A blood clot forms when fibrin, a protein in the blood, forms a mesh where blood platelets aggregate. The tissue plasminogen activator binds to the plasminogen enzyme on the blood clot to produce plasmin, which breaks up fibrin in clots and acts as an anticoagulant.
Plasminogen and its activators are naturally occurring substances in the blood released by endothelial cells in damaged blood vessels. Recombinant tissue plasminogen activator (rtPA) is synthetically produced in the labs for use in thrombolytic therapy. It is used mainly for ischemic strokes; it is not used for hemorrhagic strokes.
What is the goal of early thrombolytic therapy for ischemic stroke?
The goal of early thrombolytic therapy is to salvage the brain cells (neurons) that have suffered only partial damage, and limit the injury to the brain. Thrombolytic therapy must be administered as early as possible after symptoms of an ischemic stroke to achieve maximum benefits.
After an ischemic stroke, neurons in the core ischemic region are likely to suffer irreversible damage that results in tissue death (infarction). The neurons in the rim surrounding the infarcted area, known as the penumbra, can remain viable for up to four hours. Restoring blood supply quickly to the penumbral region improves the chances of maximum functional recovery.
Education about ischemic strokes and thrombolytic therapy is essential, so that people recognize symptoms and reach the hospital at the earliest.
The four main symptoms of an acute ischemic stroke are:
- Sudden weakness or numbness on one side of the body
- Sudden loss or change of vision
- Sudden speech difficulty or language comprehension difficulty
- Sudden dizziness or gait difficulty
If the above symptoms persist for five minutes, the patient must be immediately taken to the emergency department, preferably by paramedics.
Who is a candidate for thrombolytic therapy?
The American Heart Association/American Stroke Association (AHA/ASA) recommends the following eligibility criteria for administration of thrombolytic therapy within three hours after symptoms of ischemic stroke:
- Diagnosis of ischemic stroke causing measurable neurologic deficit
- Neurologic signs are not clearing spontaneously
- Neurologic signs are not minor and isolated
- Symptoms are not suggestive of subarachnoid (space around the brain) hemorrhage
- Onset of symptoms less than three hours before beginning treatment
- No head trauma or prior stroke in the past three months
- No heart attack (myocardial infarction) in the past three months
- No gastrointestinal or genitourinary hemorrhage in the past 21 days
- No arterial puncture in a noncompressible site during the past seven days
- No major surgery in the past 14 days
- No history of prior intracranial bleeding
- Systolic blood pressure under 185 mm Hg, and diastolic blood pressure under 110 mm Hg
- No evidence of acute trauma or bleeding
- Not taking an oral anticoagulant, or if so, the dose and type should be considered using established criteria when deciding on emergency thrombolytic therapy.
- If a stroke patient has taken heparin within the last 48 hours, they need special considerations for thrombolytic therapy.
- Platelet count of more than 100,000/microliter
- Blood glucose greater than 50 mg/dL (2.7 mmol)
- No seizure with residual post-seizure impairments
- Computed tomography (CT) scan does not show evidence of tissue death in multiple brain lobes
- The patient and family understand the potential risks and benefits of therapy
Based on favorable results from clinical trials, the AHA/ASA have revised the window of thrombolytic therapy from three hours to 4.5 hours, however, the FDA hadn’t yet endorsed this recommendation as of September 2020.
The revised AHA/ASA guidelines recommend that an eligible patient as per above criteria can receive thrombolytic therapy in the 3 to 4.5-hour window, provided the patient:
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How is thrombolytic therapy performed?
Thrombolytic therapy is administered intravenously or intra-arterially depending on the location of the clot. Ideally, the medication must be administered as quickly as possible after patient admission. The important steps taken during a thrombolytic therapy include:
Before the procedure
- A brain CT scan or MRI to confirm ischemic stroke and rule out hemorrhagic stroke
- Physical and neurological examination of the patient
- Obtaining medical history of the patient to check the patient’s eligibility for thrombolytic therapy
After the procedure
- The patient is kept in the ICU or stroke unit with close monitoring of vital signs such as
- Blood pressure
- Heart rate
- Oxygen saturation level
- No antiplatelet or anticoagulant therapy is administered for 24 hours after thrombolytic therapy
- If there is any evidence of intracerebral bleeding, a blood product known as cryoprecipitate is administered after performing emergency blood tests and CT scan
- A repeat CT scan or MRI is performed 24 hours after administration of thrombolytic therapy to check for any bleeding in the brain
After 24 hours of bedrest, initiation of functional therapies including:
What is the FDA-approved thrombolytic therapy for ischemic stroke?
Alteplase is the only FDA-approved tissue plasminogen activator for thrombolytic therapy, to be administered within three hours after onset of ischemic stroke symptoms. Thrombolytic therapy is approved only for patients who meet the eligibility criteria of the AHA/ASA guidelines.
What are the benefits and risks of thrombolytic therapy?
The primary benefit of thrombolytic therapy is improved chances of functional recovery after a stroke by revitalizing the penumbral neurons. Earlier the therapy is initiated, higher the chances of recovering most of the functional abilities.
The major complication from thrombolytic therapy is intracerebral hemorrhage, which can further worsen the situation. The symptoms of intracerebral hemorrhage include:
Other complications include:
What is the prognosis for ischemic stroke after thrombolytic therapy?
Following is the approximate prognosis for ischemic stroke patients, based on patient data recorded three months after their thrombolytic stroke therapy:
- Fifty percent of patients are completely or almost completely independent in activities of daily living.
- Fifteen percent of patients are moderately dependent on others.
- Fifteen percent of patients are completely dependent on others.
- The mortality rate is 20%.
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Related Disease Conditions
A stroke is an interruption of the blood supply to part of the brain caused by either a blood clot (ischemic) or bleeding (hemorrhagic). Symptoms of a stroke may include weakness, numbness, double vision or vision loss, confusion, vertigo, difficulty speaking or understanding speech. A physical exam, imaging tests, neurological exam, and blood tests may be used to diagnose a stroke. Treatment may include administration of clot-busting drugs, supportive care, and in some instances, neurosurgery. The risk of stroke can be reduced by controlling high blood pressure, high cholesterol, diabetes, and stopping smoking.
Stroke vs. Mini-Stroke (TIA) Differences
A stroke or "brain attack" occurs when a blood clot or artery ruptures within the brain. The rupture or clot causes brain cell damage or death. A mini-stroke (TIA, transient ischemic attack) is caused by brain cells that dysfunctional over a short period. Stroke and mini-stroke warning signs of stroke and mini stroke are the same, and include, speech problems, weakness, numbness, and facial droop. Side effects of stroke may be permanent and you may never regain full function of the parts of the body affected. Mini-stroke side effects usually resolve within minutes to a couple of days. A transient ischemic attack (mini-stroke) is a precursor for stroke because 40% of individuals who have a mini-stroke will have a stroke within a year. Treatment of stroke depends upon the type and parts of the body affected.
Early Warning Signs and Symptoms of Stroke (FAST)
Stroke is a serious medical condition. If you think you or someone you know is having a stroke call 911 immediately. There are two main types of strokes, hemorrhagic and ischemic (the most common type). A hemorrhagic stroke occurs due to a blood vessel rupture in the brain. An ischemic stroke occurs when a blood clot becomes lodged in a blood vessel in the brain, which causes a loss of blood supply to the brain, possibly causing brain tissue death. FAST is an acronym that helps people identify stroke signs and symptoms so they can act fast and call 911. Face drooping, Arm weakness, and Speech difficulty are indicators that a person may be having a stroke and it is Time to seek emergency medical treatment. Additional signs and symptoms of stroke may include weakness, difficulty walking, blurred vision, dizziness, headache, confusion, difficulty speaking, and loss of sensation. Stroke is a major cause of death and disability in the U.S. Early identification and treatment of stroke helps reduce the risk of morbidity and mortality.
Transient Ischemic Attack (TIA, Mini-Stroke)
When a portion of the brain loses blood supply, through a blood clot or embolus, a transient ischemic attack (TIA, mini-stroke) may occur. If the symptoms do not resolve, a stroke most likely has occurred. Symptoms of TIA include: confusion, weakness, lethargy, and loss of function to one side of the body. Risk factors for TIA include vascular disease, smoking, high blood pressure, high cholesterol, and diabetes. Treatment depends upon the severity of the TIA, and whether it resolves.
Migraine and Stroke
Migraine headache is a type of headache in which the exact cause is not known; however, they may be inherited, and certain foods and environmental factors can trigger and may contribute them. A stroke (brain attack) happens when a blood vessel in the brain leaks, bursts, or becomes blocked, which can be caused by many other health problems. Both migraines and strokes can can cause severe head pain (migraine pain usually is only on one side of the head). Migraine aura symptoms may mimic or feel like a stroke or mini-stroke (transient ischemic attack, TIA) because they have similar symptoms and signs like severe headache, numbness in the legs, feet, arms, hands, or face, nausea, vomiting, and dizziness. Other migraine aura symptoms include vision problems like flashing lights or blind spots in one eye. The main difference between migraine headache and stroke symptoms and signs is that a migraine headaches usually come on gradually while a stroke symptoms come on suddenly and unexpectedly.
Heat Stroke (A Very Serious Condition)
Heat stroke (heatstroke or sun stroke) is a form of hyperthermia. Heat stroke is a true medical emergency that can be fatal if not promptly and properly treated. Symptoms of heat stroke include high body temperature, absence of sweating, hot red or flushed dry skin, rapid pulse, difficulty breathing, strange behavior, hallucinations, confusion, agitation, disorientation, seizure, and coma. A victim of heat stroke must receive immediate treatment to avoid permanent organ damage.
Heart Attack vs. Stroke Symptoms, Differences, and Similarities
Heart attack usually is caused by a clot that stops blood flow supplying oxygen to an area of heart muscle, which results in heart muscle death. Stroke or "brain attack" is caused by a loss of blood supply to the brain (usually a blood clot) or by hemorrhagic stroke (bleeding within the brain), which results in brain tissue death. Both heart attack and stroke usually come on suddenly, produce similar symptoms, can be disabling, and can be fatal. The classic symptoms and warning signs of heart attack are different. Classic heart attack warning signs are chest pain or discomfort, shortness of breath, pain that radiates to the shoulders, back, arms, belly, jaw, or teeth, sweating, fainting, and nausea and vomiting. Moreover, woman having a heart attack may have additional symptoms like abdominal pain or discomfort, dizziness, clammy skin, and moderate to severe fatigue. The classic symptoms and warning signs that a person is having a stroke are confusion or loss of consciousness, sudden severe headache, speech problems, problems seeing out of one or both eyes, and numbness or weakness of only one side of the body. Moreover, a woman having a stroke may have additional warning symptom and signs like shortness of breath, disorientation, agitation, behavioral changes, weakness, nausea, vomiting, seizures, and hiccups. Recognition of stroke symptoms is vital for emergency treatment. The acronym "FAST" stands for recognition of Facial drooping, Arm weakness, Speech difficulty, and a Time for action. If you experience the symptoms heart attack or stroke (FAST) or see them develop in another person, then contact 911 immediately.
Stroke vs Aneurysm (Differences and Similarities)
A stroke or "brain attack" is caused because blood flow to an area of the brain has been cut off by a blood clot or by a weakened or damaged blood vessel (for example, head trauma). The damaged area of the brain dies, which results in loss of function like speech capabilities, muscle movement, or muscles of an extremity like an arm or leg is reduced or lost completely. An aneurysm is a weakness in an artery wall. This weakness in the wall causes the artery to widen or balloon out, and then they rupture or break open.
Warning Signs of a Stroke
Signs of a stroke may sometimes go unnoticed initially and gradually progress. Sometimes, the signs of a stroke may appear suddenly.
Stroke is the third leading killer in the United States. Some of the warning signs of stroke include sudden confusion, trouble seeing with one or both eyes, dizziness, loss of balance, and more. Stroke prevention and reatable risk factors for stroke include lowering high blood pressure, quit smoking, heart disease, diabetes control and prevention.
Types of Strokes
A stroke, also called cerebrovascular accident (CVA), occurs when the blood supply is cut off or reduced to a part of the brain. There are five main types of strokes, and the causes and clinical presentation of each of them vary
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