Unit 3 pt 2

Cerebrovascular Accident (CVA) and Pharmacological Management

Definition of CVA

Cerebrovascular Accident (CVA) is defined as a medical emergency characterized by an interruption or significant reduction of the blood supply to a specific part of the brain. This disruption leads to a lack of oxygen and essential nutrients, causing potential damage to brain tissue, which can result in long-term disabilities or death if not promptly treated.

Types of CVA

• Ischemic Stroke:

  • Caused by a clot or plaque buildup that obstructs a blood vessel, significantly reducing blood flow to the affected region of the brain.

  • Subtypes include thrombotic (clots formed in the brain arteries) and embolic (clots formed elsewhere in the body that travel to the brain).

• Hemorrhagic Stroke:

  • Results from the rupture of a blood vessel in or around the brain, leading to bleeding within the cranial cavity.

  • Types include intracerebral hemorrhage (bleeding within the brain) and subarachnoid hemorrhage (bleeding in the space surrounding the brain).

• Transient Ischemic Attack (TIA):

  • Often referred to as a "mini-stroke," a TIA presents symptoms similar to a stroke yet lasts only a few minutes to hours, with no lasting damage.

  • It's a significant warning sign and can predict future stroke risk.

Types of Cerebral Vascular Injuries

• Middle Cerebral Artery (MCA):

  • Damage typically results in contralateral hemiparesis and sensory deficits, notably affecting the arm more than the leg due to the anatomical layout of motor control in the brain.

• Anterior Cerebral Artery (ACA):

  • Leads to contralateral hemiparesis and sensory deficits, with the leg being more affected than the arm, which is crucial for rehabilitation strategies focusing on lower extremity function.

• Posterior Cerebral Artery (PCA):

  • Can cause memory deficits, visual agnosia (difficulty recognizing familiar objects), and contralateral homonymous hemianopia (loss of half of the visual field in both eyes).

Stroke and Aphasia Types

• Types of Aphasia:

  • Receptive Aphasia:

    • Patients exhibit difficulty understanding incoming sensory language information, leading to misunderstandings in communication.

  • Expressive Aphasia:

    • Patients can comprehend incoming language but experience challenges in producing language responses, impacting their ability to communicate effectively.

FAST and BEFAST

• Recognizing CVA Symptoms:

  • F.A.S.T:

    • Face: Ask the person to smile. Observe for drooping on one side.

    • Arms: Check if the person can raise both arms equally.

    • Speech: Determine if speech is slurred or strange.

    • Time: Call emergency services immediately if any symptoms are observed, as timely intervention is crucial.

  • B.E.F.A.S.T:

    • Additional symptoms include:

      • Balance: Sudden loss of balance or coordination.

      • Eyesight: Sudden trouble seeing in one or both eyes.

Pharmacological Management of Acute Ischemic Stroke

• Fibrinolytic or Thrombolytic Drugs:

  • Designed to facilitate the breakdown of blood clots, these medications are most effective when administered within a 3-hour window after onset of symptoms.

  • Risks: Can include serious bleeding complications post-treatment, emphasizing the need for careful patient selection.

• Antithrombotic Drugs ("blood thinners"):

  • Anticoagulants: Control clotting factors, used for conditions such as atrial fibrillation, deep vein thrombosis (DVT), and pulmonary embolism (PE).

  • Antiplatelet Drugs: Prevent abnormal platelet activity and formation of clots, especially in the case of ischemic strokes.

Fibrinolytic Drug Indications

Conditions for Use:

• Primarily indicated for acute ischemic stroke, acute myocardial infarction, peripheral artery occlusion, large vein DVTs, and massive pulmonary embolism.

Important Timing:

• "Door-to-needle" times are critical for effective treatment: within 3 hours for ischemic strokes and within 12 hours for myocardial infarction.

Mechanism:

• Fibrinolytic drugs activate plasminogen to plasmin, leading to the breakdown of fibrin within clots. Routes of administration include intravenous (IV) or intra-arterial.

Drugs:

• Commonly used medications include Urokinase, alteplase (Activase®), reteplase, and tenecteplase.

Adverse Effects of Fibrinolytic Drugs

• Major Risk: Hemorrhage or bleeding stands out as the most serious adverse effect following administration.

• Other Risks: Minor side effects can include itching, nausea, headache, and potential allergic reactions.

Anticoagulants

• Types:

  • Heparin: Provides an immediate anticoagulation effect, commonly used for acute DVT and PE management.

  • Warfarin: Typically for long-term management, it requires ongoing monitoring of prothrombin time (PT) and international normalized ratio (INR).

  • Direct Thrombin Inhibitors and Factor Xa Inhibitors: Newer choices with fewer adverse effects compared to traditional anticoagulants.

Heparin and Its Types

• Unfractionated Heparin (UFH):

  • Requires frequent intravenous administration and regular monitoring to adjust dosing.

• Low Molecular Weight Heparins (LMWH):

  • Offers a more predictable response and can often be administered subcutaneously, preferred in many clinical settings.

Heparin-Induced Thrombocytopenia (HIT)**

• Description:

  • A reduction in platelet count that increases the risk of thrombosis; HIT can be classified into Type I (mild decrease) and Type II (severe decrease).

Warfarin

• Mechanism:

  • Acts by inhibiting vitamin K-dependent clotting factors produced in the liver, crucial for coagulation.

• Transition:

  • Patients may be transitioned from heparin to warfarin for ongoing anticoagulation treatment following initial stabilization.

Direct Thrombin Inhibitors

• Overview:

  • Bind directly to thrombin, providing another option for managing thromboembolic events.

• Key Drugs:

  • Include Bivalirudin, desirudin, and lepirudin.

Factor Xa Inhibitors

• Description:

  • These directly inhibit Factor Xa, offering a lower risk of HIT compared to traditional anticoagulants.

• Key Drugs:

  • Examples include Fondaparinux, rivaroxaban, and apixaban.

Antiplatelet Drugs

• Types:

  • Include Aspirin, ADP receptor blockers (such as clopidogrel), and glycoprotein IIb-IIIa receptor blockers.

• Aspirin:

  • Primarily used to prevent thrombus formation in cases of myocardial infarction and ischemic stroke; not recommended for hemorrhagic strokes.

Clinical Considerations for Antiplatelet Therapy

• ADP Receptor Blockers:

  • Generally more effective than aspirin, often utilized in dual antiplatelet therapy for patients at high risk for thrombotic events.

• Glycoprotein IIb-IIIa Receptor Blockers:

  • Administered during percutaneous coronary interventions (PCI); act as potent inhibitors of platelet aggregation.

Intracerebral Hemorrhage (ICH)

• Definition:

  • Characterized by bleeding from an arterial source directly into brain tissue; ICH is regarded as one of the deadliest forms of stroke.

• Symptoms: Include sudden headache, vomiting, decreased alertness, and focal neurological deficits.

• Rehabilitation Implications: Treatment plans must focus on minimizing further bleeding risk and addressing injurious factors; caution is necessary with manual therapies due to increased risk of complications.

Managing ICH

• Key Protocols:

  • Immediate measures include airway management, control of blood pressure, and addressing cerebrospinal fluid pressure;

• Blood Pressure Management:

  • Critical to both prevent further hemorrhage and ensure adequate cerebral perfusion; may require aggressive treatment strategies.

• ICP Control:

  • Use of osmotic agents, such as Mannitol, may be essential for reducing cerebral edema and intracranial pressure.

Special Considerations for Rehabilitation

• A multidisciplinary approach is favorable, addressing factors such as patient adherence to antihypertensives, recognition and management of mood disorders, and optimization of metabolic factors like glucose levels during post-ICH recovery.

Pharmacology: Skeletal Muscle Relaxants

• Indications:

  • Commonly prescribed for conditions generating spasticity from CVA, cerebral palsy, multiple sclerosis, and spinal cord injuries.

• Goals of Treatment:

  • Aiming to normalize muscle excitability with minimal functional loss while alleviating pain; tailored interventions are key for each patient.

Categories of Muscle Relaxants

• Anti-spasm Drugs:

  • Target various sites, including the central nervous system and neuromuscular junctions.

• Anti-spasticity Drugs: Specifically intended to manage spasticity while improving patients' functional capabilities.

Common Skeletal Muscle Relaxants

• Examples:

  • Baclofen: Acts on GABA receptors in the spinal cord and is highly effective in reducing severe spasticity.

  • Dantrolene Sodium: Functions directly on muscles, useful for severe spasticity, but may lead to adverse effects such as hepatotoxicity.

Botulinum Toxin

• Actions and Indications:

  • Acts by preventing acetylcholine release at neuromuscular junctions; effective in treating spasticity, dystonias, and certain chronic pain syndromes.

Screening for Neurological System

• Screening Techniques:

  • Employ tests like Babinski reflex, clonus tests, and ocular screenings to assess neurological function.

• Subjective History Questions:

  • Important to collect history of neurological symptoms, dizziness, or other relevant medical issues during patient interviews.

Physician Referral Guidelines

• When to Refer:

  • Patients exhibiting behavioral changes, unexplained weakness, or other alarming neurological signs should be promptly referred to a physician for further evaluation.

Neuroimaging Techniques

• CT vs. MRI:

  • CT:

  • Typically preferred for acute situations, providing rapid assessment for recent hemorrhage or trauma.

  • MRI:

  • Superior for detecting chronic conditions, ischemia, and edema compared to CT.

Common Pathologies in Imaging

• Acute and Chronic Conditions:

• Ischemic Stroke:

  • Appears on CT initially as bright vessels, transitioning to darker areas indicating increased edema over time.

• Multiple Sclerosis:

  • MRI findings often reveal plaques indicative of demyelination; T1 images may show black holes corresponding to chronic lesions.

• Alzheimer’s Disease:

  • Enlarged ventricles can be observed on both CT and MRI, indicative of neurodegenerative change.

Conclusion

Employing comprehensive knowledge of cerebrovascular incidents—spanning their definition, types, management strategies, and imaging techniques—is essential for effective patient care and rehabilitation strategies. Understanding the pharmacological interventions available and their implications will guide healthcare providers in optimizing outcomes for those affected by CVA.