This chapter is specifically tailored for pharmacy students preparing for the Pharmacy Examining Board of Canada (PEBC) exams, focusing on both the Evaluating Exam (EE) and Qualifying Exam (MCQ). Understanding the diagnosis and management of acute stroke is a critical competency for pharmacists, especially those practicing in emergency or hospital settings. Stroke is a leading cause of disability and death, and pharmacists play an essential role in optimizing pharmacotherapy, ensuring timely intervention, and preventing further complications.

This chapter will guide you through the essentials of Acute Stroke diagnosis, therapeutic options, pharmacologic treatments, and red flags. It will also provide the necessary tools to answer stroke-related questions on the PEBC exams effectively.

Comprehensive Summary for PEBC Exams

Overview of Acute Stroke

Acute stroke is a neurological emergency, classified primarily into two types:

• Ischemic Stroke: Responsible for about 85% of all stroke cases, caused by a clot obstructing blood flow to the brain.

• Hemorrhagic Stroke: Caused by the rupture of a blood vessel, leading to bleeding in or around the brain.

A related condition, Transient Ischemic Attack (TIA), often referred to as a "mini-stroke," involves temporary neurological symptoms without lasting damage. TIAs are significant predictors of future strokes and should always be treated as emergencies.

Stroke Pathophysiology

• Ischemic Stroke: Occurs due to obstruction of a cerebral artery by a clot, leading to decreased oxygen supply (hypoxia) and death of brain tissue (infarction). The most common cause is atherosclerosis.

• Hemorrhagic Stroke: Results from a weakened blood vessel rupturing, typically due to hypertension or an aneurysm. It leads to increased intracranial pressure and further brain damage.

Stroke Symptoms – F.A.S.T. Recognition

Pharmacists should be familiar with the FAST mnemonic to recognize stroke signs:

• Face: Is one side of the face drooping?

• Arms: Can the person raise both arms?

• Speech: Is speech slurred or incoherent?

• Time: Time is critical; call 911 immediately.

Goals of Therapy for Acute Stroke

The primary objectives in managing acute stroke are:

1. Minimize brain damage: Early treatment is critical to salvage brain tissue.

2. Prevent complications: This includes preventing post-stroke complications like pneumonia, venous thromboembolism (VTE), and aspiration pneumonia.

3. Restore function and minimize long-term disability: Rehabilitation should begin as soon as medically feasible.

4. Prevent recurrence: Long-term strategies include controlling hypertension, hyperlipidemia, and diabetes, and managing antiplatelet or anticoagulant therapy.

Diagnostic Process for Acute Stroke

Time is brain—this phrase emphasizes the importance of swift diagnosis and treatment. For the PEBC exams, understanding the diagnostic workup for suspected stroke is vital.

Key Diagnostic Steps:

1. Clinical History and Examination:

• Establish the time of symptom onset or when the patient was last known to be well.

• Assess for risk factors such as hypertension, atrial fibrillation, diabetes, smoking, and family history of stroke.

• Perform a neurological exam using tools like the NIH Stroke Scale to assess stroke severity.

2. Immediate Imaging:

• Non-contrast CT scan is the first-line imaging tool to differentiate ischemic from hemorrhagic stroke.

• CT angiography (CTA) helps identify large artery occlusions and can guide endovascular treatment decisions.

• MRI may be used if CT is inconclusive, particularly in cases of wake-up strokes where the exact time of onset is unclear.

3. Laboratory Tests:

• Complete blood count (CBC), coagulation tests (INR, PTT), glucose, and renal function tests are essential to rule out stroke mimics and identify contraindications for thrombolysis.

4. Cardiac Evaluation:

• Stroke caused by embolic events from the heart may require ECG and echocardiography to detect conditions like atrial fibrillation or valvular heart disease.

Red Flags in Diagnosis:

• Sudden severe headache, which could indicate a subarachnoid hemorrhage.

• Unconsciousness or reduced consciousness.

• Progressive neurological deterioration.

Pharmacologic Management in Stroke

Management of stroke depends on the type (ischemic or hemorrhagic), the time since onset, and the patient’s clinical condition.

Pharmacotherapy for Ischemic Stroke

1. Thrombolytics:

• The cornerstone of ischemic stroke treatment is alteplase (rtPA), a tissue plasminogen activator that breaks down blood clots.

• Dosage: 0.9 mg/kg (maximum 90 mg) IV over 60 minutes, with 10% of the dose given as an initial bolus.

• Indications: Must be administered within 4.5 hours of symptom onset.

• Monitoring: Close monitoring of blood pressure, neurologic status, and signs of bleeding is critical during and after thrombolysis.

2. Antiplatelet Therapy:

• Aspirin (ASA): 160 mg given immediately after ischemic stroke (if hemorrhage is excluded) to reduce further clot formation.

• For secondary prevention, clopidogrel (75 mg once daily) or ASA/dipyridamole may be used, especially in patients with recurrent strokes or contraindications to aspirin.

3. Anticoagulants:

• Direct oral anticoagulants (DOACs) such as apixaban and rivaroxaban are used for stroke prevention in patients with atrial fibrillation.

• Warfarin is also used but requires regular INR monitoring.

Red Flags in Pharmacotherapy:

• Hemorrhagic transformation: Occurs when thrombolytics cause a secondary bleed.

• Contraindications for thrombolysis: History of hemorrhagic stroke, major surgery within 14 days, severe uncontrolled hypertension (>185/110 mmHg).

Hemorrhagic Stroke Management

1. Blood Pressure Control:

• Aggressive blood pressure management (typically reducing systolic BP to <140 mmHg) is crucial to minimize further bleeding.

2. Surgical Intervention:

• In some cases, decompressive surgery (e.g., hemicraniectomy) may be needed to relieve pressure from brain swelling.

3. Reversal of Anticoagulation:

• If a hemorrhagic stroke occurs in patients on anticoagulants, reversal agents like prothrombin complex concentrate (PCC) or vitamin K may be administered.

Treatment Algorithms

Ischemic Stroke Algorithm:

1. Initial Assessment (FAST, CT imaging) →

2. If Ischemic Stroke and within 4.5 hours → Administer rtPA →

3. If large vessel occlusion → Consider endovascular thrombectomy →

4. Secondary prevention: Start antiplatelet or anticoagulant therapy after exclusion of hemorrhage.

Hemorrhagic Stroke Algorithm:

1. Initial Assessment (FAST, CT imaging) →

2. If Hemorrhagic Stroke → Initiate blood pressure control →

3. Consider surgical intervention if large hemorrhage →

4. Reversal of anticoagulation if needed.

Comprehensive Drug Tables

Red Flags in Acute Stroke

Recognizing red flags early can drastically improve patient outcomes:

1. Severe headache (sudden onset): Often a sign of subarachnoid hemorrhage.

2. Unconsciousness or rapidly declining consciousness: May indicate a large hemorrhage or increasing intracranial pressure.

3. Persistent vomiting or nausea: Associated with increased intracranial pressure.

4. Neurological symptoms on waking: Often seen in ischemic strokes, requiring prompt imaging and intervention.