Chapter 33_2 flashcards
(14 cards)
Ischemic Stroke: Main Causes
- Atrial Fibrillation: Clots form in the quivering left atrium and travel to the brain (cardioembolic event). 2. Carotid Stenosis: Atherosclerotic plaque narrows the carotid artery, leading to thrombus formation or embolization. 3. Cerebral Arteriosclerosis: Plaque buildup directly within a cerebral artery.
Stroke Symptoms: General Manifestations
Symptoms are typically contralateral (opposite side) to the brain hemisphere affected. Common signs: hemiparesis (unilateral weakness), hemiplegia (unilateral paralysis), loss of sensation, facial droop, and slurred speech (dysarthria).
Stroke Symptoms: Left vs. Right Hemisphere
Left Hemisphere Stroke: Often causes aphasia (expressive, receptive, or global) in addition to right-sided motor/sensory deficits. Right Hemisphere Stroke: Often causes left-sided motor/sensory deficits and may involve issues with spatial relationships and facial recognition.
Stroke Acronym: FAST
Used to recognize stroke signs: Facial droop, Arm weakness, Speech difficulty, Time to call 911.
Hemorrhagic Stroke: Main Cause
Hypertension is the major predisposing factor, as it weakens cerebral artery walls. Rupture of a cerebral aneurysm or an arteriovenous malformation (AVM) are other common causes.
Subarachnoid Hemorrhage (SAH): Cause & Key Symptom
A type of hemorrhagic stroke caused by rupture of an artery in the subarachnoid space, often from a cerebral aneurysm. Key symptom is a sudden, severe “thunderclap headache” described as the “worst headache of my life.”
Stroke Diagnosis: Initial and Most Important Test
A non-contrast CT scan of the head is the priority. It is essential to rapidly differentiate between an ischemic and hemorrhagic stroke, as treatments are completely different and time-sensitive.
NIH Stroke Scale (NIHSS): Purpose
A graded neurological examination used to quantify the severity of neurological deficits caused by a stroke and to track patient progress during treatment.
Ischemic Stroke Treatment: Thrombolysis (rt-PA)
Recombinant tissue-type plasminogen activator (rt-PA), a “clot-busting” drug, can dissolve the thrombus and restore blood flow. It must be administered within a strict 3 to 4.5-hour window from the onset of symptoms.
Ischemic Stroke Treatment: Mechanical Thrombectomy
A surgical procedure where a stent retriever is used to physically remove a large clot from a cerebral artery. It can be performed within 6 to 24 hours of symptom onset in eligible patients, often after rt-PA has been attempted.
Ischemic Stroke: Long-Term Prevention
Lifestyle modifications (diet, exercise, smoking cessation), antiplatelet drugs (aspirin, clopidogrel), anticoagulants (for atrial fibrillation), and management of carotid stenosis (carotid endarterectomy or stenting).
Hemorrhagic Stroke: Treatment Priorities
- Hemodynamic stabilization. 2. Control blood pressure (slowly, to a target like SBP <150 mmHg). 3. Manage cerebral edema (using IV mannitol or hypertonic saline). 4. Surgical evacuation of the hematoma may be possible depending on location and size.
Hemorrhagic Stroke: Managing Anticoagulation
If the patient was on anticoagulant therapy, it must be reversed immediately. For example, Vitamin K reverses warfarin, and protamine sulfate reverses heparin.
Hemorrhagic Stroke: Surgical Interventions
Surgical options include craniotomy with hematoma evacuation or endovascular procedures like coil embolization or microsurgical clipping for a ruptured aneurysm or AVM.
