TN Stroke Flashcards
What is infarction?
permanent tissue injury, confirmed by neuroimaging (vascular etiology)
What is stroke?
sudden onset of neuro deficits of a vascular etiology with infarction of CNS tissue
What is TIA?
sudden onset of neuro deficits of a vascular etiology without infarction of CNS tissue (no imaging evidence of stroke)
What is amaurosis fugax?
transient monocular painless vision loss (can be presentation of TIA)
What is hypertension encephalopathy?
Encephalopathy caused by acute severe HTN (typically dBP>130 of sBP>200)
What are the clinical findings of hypertension encephalopathy?
- abn fundoscopy (papilledema, hemorrhages, exudates, cotton-wool spots)
- focal neuro Sx
- N/V
- visual disturbances
- change in LOC
What are the two major types of stroke, and what is the proportion of each?
Ischemic (80%) and hemorrhagic (20%)
What are the three major etiologies/pathophys of ischemic stroke?
arterial thrombosis (large or small vessel)
cardioembolic
systemic hypoperfusion
What is the mechanism of large vessel thrombotic stroke, and which are considered “large”?
stenosis or occlusion –> insufficient blood flow beyond lesion (hemodynamic stroke)
Internal carotid artery, vertebral, or intracranial arteries
What are the etiologies/pathophys of large vessel stroke?
atherosclerosis (most common cause)
dissection
vasculitis
What is the mechanism of large vessel thrombotic stroke, and which are considered “small”?
chronic HTN and DM cause vessel wall thickening and decreased luminal diameter
affects mainly small penetrating arteries (primarily basal ganglia, internal capsule, and thalamus)
What is the mechanism of cardioembolic stroke?
blockage of cerebral arterial blood flow due to particles originating from a cardiac source
What conditions can cause cardioembolic stroke?
atrial fibrillation (most common) rheumatic valve disease prosthetic heart valves recent MI fibrous and infectious endocarditis
What is the mechanism of stroke due to systemic hypoperfusion?
inadequate blood flow to brain, usually secondary to cardiac pump failure (e.g. cardiac arrest,
arrhythmia, or MI)
What areas are affected in stroke due to systemic hypoperfusion?
There is global cerebral ischemia; primarily affects watershed areas
What are the main types of hemorrhagic stroke?
intracerebral hemorrhage
subarachnoid hemorrhage
What are the mechanisms of intracerebral hemorrhage?
hypertensive (most common) trauma amyloid angiopathy (associated with lobar hemorrhage) vascular malformations vasculitis drug use (cocaine or amphetamines)
What is the difference between the aneurysms that cause intracerebral vs other intracranial hemorrhage?
Intracerebral hemorrhage: smaller microaneurysm in penetrating vessels
other: on larger vessels
[this is my interpretation, would be worth double checking]
What is a subarachnoid hemorrhage?
bleeding into subarachnoid space (intracranial vessel between arachnoid and pia)
What are the main causes of SAH?
trauma (most common) spontaneous: ruptured aneurysms (75-80%), idiopathic (14-22%), AVMs (4-5%) other: coagulopathies (iatrogenicorprimary) vasculitides tumours cerebral artery dissections
What are the clinical features of SAH?
• sudden onset (seconds) of severe “thunderclap” H/A usually following exertion and described as the “worst headache of my life” (up to 97% sensitive, 12-25% specific)
• N/V, photophobia
• meningismus (neck pain/stiffness, positive Kernig’s and Brudzinski’s sign)
• decreased LOC (due to any of: raised ICP, ischemia, seizure)
• focal deficits: cranial nerve palsies (CN III, IV), hemiparesis
• ocular hemorrhage in 20-40% (due to sudden raised ICP compressing central retinal vein)
• reactive HTN
also, Hx of sentinel bleed
What is a sentinel bleed (in context of SAH)?
■ represents undiagnosed SAH
■ SAH-like symptoms lasting <1 d (“thunderclap H/A”)
■ may have blood on CT or LP
■ ~30-60% of patients with full blown SAH give history suggestive of sentinel bleed within past 3 wk
What Ix should be done to assess for SAH?
• non-contrast CT – for diagnosis of SAH
• lumbar puncture (highly sensitive) – for diagnosis of SAH if CT negative but high suspicion
• four vessel cerebral angiography (“gold standard” for aneurysms)
• MRA and CTA: sensitivity upto 95% for aneurysms, CTA>MRA for smaller aneurysms and delineating adjacent bony anatomy
[see TN for more details on findings for each]
What particular features should be assessed in neurological exam of suspected SAH?
BP LOC Limb movements Stiff neck Fundi [this is from the neurosurgery section, so, sparse]
What is the syndrome of an ACA stroke?
contralateral leg paresis, sensory loss, cognitive deficits (e.g. apathy, confusion, and poor judgment)
What is the syndrome of an MCA stroke?
proximalocclusioninvolves:
- contralateral weakness and sensory loss of face and arm
- cortical sensory loss
- may have contralateral homonymous hemianopia or quadrantanopia
- if dominant (usually left) hemisphere: aphasia
- if non-dominant (usually right) hemisphere: neglect
- eye deviation towards the side of the lesion and away from the weak side
What is the syndrome of a PCA stroke?
- contralateral hemianopia or quadrantanopia
- midbrain findings: CN III and IV palsy/pupillary changes, hemiparesis
- thalamic findings: sensory loss, amnesia, decreased level of consciousness 4. if bilateral: cortical blindness or prosopagnosia
- hemiballismus
What is the syndrome of a proximal basilar artery stroke?
proximal (usually thrombosis): impaired EOM, vertical nystagmus, reactive miosis, hemi- or
quadriplegia, dysarthria, locked-in syndrome, coma
What is the syndrome of a distal basilar artery stroke?
distal (usually embolic, i.e. top of the basilar sydrome): somnolence, memory and behaviour
abnormalities, oculomotor deficit
What is the syndrome of a PICA stroke?
ipsilatera lataxia, ipsilateral Horner’s, ipsilateral facial sensory loss;
contralateral limb impairment of pain and temperature sensation;
nystagmus, vertigo, nausea/vomiting;
dysphagia, dysarthria, hiccups
What are other names for the PICA stroke syndrome?
lateral medullary or Wallenberg syndrome
What is the syndrome of a medial medullary stroke, and what artery is involed?
contralateral hemiparesis (facial sparing), contralateral impaired proprioception and vibration sensation, ipsilateral tongue weakness
(anterior spinal artery, which can be associated with anterior cord infarct)
What structures are involved in lacunar infarcts?
Deep hemispheric white matter; involving deep penetrating arteries of MCA, circle of Willis, basilar, and vertebral arteries