Acute Stroke
Basilar Artery
Pons (locked-in syndrome) Bilateral: progressive quadriplegia, facial weakness Lateral gaze weakness with sparing of vertical gaze
Different types of ischemic stroke
*large-artery atherosclerosis*:High-grade stenosis or occlusion of the major intra- and extracranial arteries, which include the internal carotid artery, the vertebral artery, the basilar artery, and other major branches of the circle of Willis, occur due to deposition of plaque and often leads to a flow-dependent state of perfusion *cardioembolism*: Turbulent or stagnant flow states in the heart can result in formation of thrombi. These thrombi can dislodge and occlude blood vessels in the intracranial circulation farther downstream. The most common cause of cardioembolic stroke is atrial fibrillation. *small vessel disease*: Changes in the arterial vasculature of small perforating arteries can result in narrowing of the vessel lumen and eventual occlusion. Chronic hypertension is one state that leads to vessel damage secondary to lipohyalinosis and endothelial damage. These changes often result in lacunar infarcts, which are small infarcts defined by their size (<15 mm3) and are typically located in deep structures such as the internal capsule, basal ganglia, thalamus, and brainstem.
What are 3 symptoms that incrase the odds of a stroke being present?
Facial paresis, arm drift, and abnormal speech
Stroke Rehabilitation:
Goal is to restore as much independence as possible PT: gross motor skills Occupational therapy: fine motor skills Speech therapy Health counselor psychologist/therapist
What are some risk factors for ischemic stroke? hmeorrhagic stroke?
Ischemic: HTN, DM, A fib, smoking, hyperlipidemia, carotid stenosis Hemorrhage: hypertension, amyloid angiopathy, anticoagulant use, thrombolytic use
Determining the location of the lesion: Anterior Cerebral Artery (2%)
Mostly affects frontal lobe Contralateral *Greater in Leg/foot* > upper extremity *face is usually spared*, speech preservation Frontal lobe & mental status impairment: impaired judgement, confusion, *personality changes*
What is the Diagnostic approach for strokes?
Noncontrast CT scan to rule out hemorrhage in suspected stroke. - CT scan may be normal during 1st 6-24 hours
Posterior Cerebral Artery:
Occipital lobe Contralateral *Homonymous hemianopia*(visual field loss on the left or right side of the vertical midline) *crossed sx*: ipisilateral cranial nerve loss + contralateral muscle weakness
Middle Cerebral Artery (70%)
Posterior frontal, temporal, and parental lobes Contralateral * face and arm > leg weakness*, sensory loss to all modalities, visual field cut, visual-spacial neglect *ipsilateral: gaze preference* Dominant hemisphere affected (usually L sided): aphasia, ataxia, agraphia
Ischemic Stroke Management:
Thrombolytics iwthin 3 hours of onset Tissue plasminogen activator (rTPA) *Alteplase* - given if no evidence of hemorrhage. Only effective in ischemic stroke. *CI*: BP >185/110, recent bleep/trauma Antiplatelet therapy: aspirin, clopidogral. Aspirin used in the acute setting if after 3 hours & thrombolytics aren't given or at least 24 hours after thrombolytics * strokes with facial involvement involves the Lower half of face* -- (patient will still be able to raise both eyebrows)
TIA:
Transient episode of neurological deficits caused by focal brain, spinal cord, or retinal eschemia *without acute infarction*. *often lasting < 24 hours* - most resolve in 30-60 minutes. *MC due to embolus* or transient hypotension 50% of patients with TIA will have a CVA within 1st 24-48 hours afterwards. 10-20% will experience CVA within 90 days. manifestations: *Internal Carotid Artery- Amaurosis Fugax (monocular vision loss- temporary "lamp shade down on one eye"), weakness contralateral hand* Vertebrobasilar: brainstem/cerebellar symptoms Dx: CT: initial test of choice Management: Aspririn +/- Dipyridamole or Clopidogrel (Plavix) - *thrombolytics contraindicated*
Possible etiologies of acute hemiparesis or sensory changes:
Vascular Etiologies: - Ischemic stroke - ICH - Carotid or vertebral dissection - subarachnoid hemorrhage - subdural/epidural hematoma - HTN crisis Electrical: - seizure with postictal Todd's paralysis - complicated migraine Infectious: - encephalitis - Cerebral Abscess - Empyema Immunologic: - MS Toxic/Metabolic/Systemic: - electrolyte abnormalities (in patients with prior stroke) - UTI/PNA
Different types of Hemorrhagic Stroke:
Weakening of the blood vessel wall is often a result of chronic uncontrolled hypertension or a problem intrinsic to the blood vessel such as amyloid angiopathy or other vascular malformation. In hypertension, microaneurysms in perforating vessels, known as Charcot-Bouchard aneurysms, can rupture and cause bleeding. *The thalamus, basal ganglia, pons, and cerebellum are the most common sites for these hypertensive bleeds. Lobar hemorrhages more commonly result from amyloid angiopathy, which is typically seen in older patients.* *Spontaneous ICH*: commonly caused by HTN, especially in basal ganglia. *subarachnoid hemorrhage*: sudden *worse HA of my life* - brief LOC, N/V and meningeal irritation signs, MC due to rupture of berry aneurysm *Berry Aneurysm*: MC circle of Willis (asymptomatic until SAH) - *angiography is the gold standard*
