Stroke Lecture 1 PDF

Dr. Harith Al-Qazaz Stroke  A stroke, or cerebrovascular accident (CVA), is defined as an abrupt onset of a neurologic deficit that lasts at least 24 hours and is presumed to be of vascular origin  Transient ischemic attacks (TIAs) are ischemic neurologic deficits lasting less th...

Dr. Harith Al-Qazaz Stroke  A stroke, or cerebrovascular accident (CVA), is defined as an abrupt onset of a neurologic deficit that lasts at least 24 hours and is presumed to be of vascular origin  Transient ischemic attacks (TIAs) are ischemic neurologic deficits lasting less than 24 hours and usually less than 30 minutes.  Stroke can be either ischemic or hemorrhagic in origin. Approximately 85% of strokes are ischaemic and 15% haemorrhagic. Stroke Risk Factors for Stroke  Non-modifiable risk factors for stroke include increased age, male gender, and heredity.  Modifiable risk factors include hypertension and cardiac disease (e.g., CAD) diabetes mellitus, dyslipidemia, and cigarette smoking Pathophysiology A-Ischemic Stroke:  Ischemic strokes are due either to local thrombus formation or to emboli where the clot forms elsewhere in the body before it is transported to the brain to occlude a cerebral artery. The final result is decreasing cerebral blood flow causing ischemia and infarction B-Hemorrhagic Stroke:  A haemorrhagic stroke occurs when there is bleeding from the vessels within the brain (intracranial) or the vessels on the surface of the brain into the space between the skull and the brain (subarachnoid).  The presence of blood in the brain causes damage to the tissue through a mass effect and the neurotoxicity of blood components Clinical Presentation  Patients may be unable to provide a reliable history because of neurologic deficits. Family members or other witnesses may need to provide this information. Symptoms include  unilateral weakness, inability to speak, loss of vision, vertigo, or falling.  Ischemic stroke is not usually painful, but headache may occur in hemorrhagic stroke.  Neurologic deficits on physical examination depend on the brain area involved. Hemi- or monoparesis and hemisensory deficits are common.  Patients with posterior circulation involvement may have vertigo and diplopia. Anterior circulation strokes commonly result in aphasia.  Patients may experience dysarthria, visual field defects, and altered levels of consciousness. Diagnosis  The priority is usually to determine the type of stroke suffered This is achieved through the use of CT scan or MRI of the brain.  Further tests are done to establish risk factors for the stroke event (such as BP for hypertension, blood glucose for diabetes and ECG for the presence of arrhythmias).  Carotid Doppler (CD), transthoracic echocardiogram (TTE), and transcranial Doppler (TCD) studies can each provide valuable diagnostic information. Treatment  Goals of Treatment: The goals are to: (1) reduce ongoing neurologic injury and decrease mortality and long-term disability; (2) prevent complications secondary to immobility and neurologic dysfunction; and (3) prevent stroke recurrence. General Approach  Ensure adequate respiratory and cardiac support and determine quickly from CT scan whether the lesion is ischemic or hemorrhagic.  Elevated blood pressure (BP) should remain untreated in the acute period (first 7 days) after ischemic stroke to avoid decreasing cerebral blood flow and worsening symptoms.  BP should be lowered if it exceeds 220/120 mm Hg or there is evidence of aortic dissection, acute myocardial infarction (MI), pulmonary edema, or hypertensive encephalopathy. Non-Pharmacological Treatment  Acute ischemic stroke: Endovascular thrombectomy with a stent retriever (done within 6 hours of symptom onset) improves outcomes in select patients with proximal large artery occlusion. Surgical decompression (performed within 48 hours of stroke onset in patients less than age 60) is sometimes necessary to reduce intracranial pressure.  Hemorrhagic stroke: In subarachnoid hemorrhage from ruptured intracranial aneurysm or arteriovenous malformation, surgical intervention to clip or ablate the vascular abnormality reduces mortality from rebleeding. After primary intracerebral hemorrhage, surgical evacuation may be beneficial in some situations, but this remains under investigation. Pharmacologic Therapy of Ischemic Stroke 1-Thrombolysis: All patients with an ischemic stroke within 4.5 hours of onset should receive thrombolytic treatment with intravenous tissue plasminogen activator (tPA) because it is effective in improving stroke outcome.  2-Brain oedema develops between the second and fifth day after stroke onset, with symptoms and signs of increasing intracranial pressure (ICP). Elevated ICP is managed by head elevation and osmotic agents such as mannitol. Pharmacologic Therapy of Ischemic Stroke 3-Maintenance of an adequate cerebral perfusion pressure helps prevent further ischemia. Attempts to lower the blood pressure of hypertensive patients during the acute phase (i.e., within 2 weeks) (first 7 days) of a stroke should generally be avoided, as lowering the blood pressure may further compromise ischemic areas. However, the pressure should be lowered if it exceeds 220/120 mm Hg [short-acting parenteral agents (e.g., labetalol, nicardipine, and nitroprusside) are preferred]. Pharmacologic Therapy of Ischemic Stroke 4- Aspirin is the only antiplatelet agent that has been proven effective for the acute treatment of ischemic stroke; Aspirin should be started between 24 and 48 hours after completion of alteplase. In patients not eligible for thrombolytic therapy, the immediate administration of aspirin 325 mg orally daily is indicated. 5-Anticoagulant drugs should be started in the setting of atrial fibrillation or other source of cardio-embolism. Treatment is with warfarin (target INR 2.0–3.0) or dabigatran. Pharmacologic Therapy of Ischemic Stroke Secondary prevention 1-Antiplatelets : Aspirin, clopidogrel, and the combination of aspirin plus extended-release dipyridamole are the antiplatelet agents most commonly used for this purpose 2-Anticoagulant: In all patients with atrial fibrillation who have suffered a stroke, anticoagulation should aim for INR of 2.0 to 3.0. 3-Statins: treatment with statins reduces the risk of recurrent stroke. 4-Elevated blood pressure is common after ischemic stroke, ACE inhibitor and a diuretic are usually considered for reduction of blood pressure in patients with stroke or TIA after the acute period (first 7 days). Pharmacologic Therapy of Ischemic Stroke Inclusion and Exclusion Criteria for tPA Use in Acute Ischemic Stroke Inclusion criteria  Age 18 years or older  Clinical diagnosis of ischemic stroke causing a measurable neurologic deficit  Time of symptom onset well established to be 1.7) or PT (>15 seconds)  Significant head trauma or previous stroke within 3 months  Arterial puncture at noncompressible site within 7 days  Intracranial neoplasm, arteriovenous malformation, or aneurysm  SBP >185 mm Hg or DBP >110 mm Hg  Blood glucose