Medicine - Neuro Flashcards
Most common parts of the brain affected by lacunar strokes
Lacunar stroke - affect subcortical areas of cerebrum and brainstem. Most commonly basal ganglia, thalamus, pons, and internal capsule.
Most common sites for intracranial hemorrhage 2/2 Hypertensive vasculopathy?
Putamen (44%) Thalamus (13%) Cerebellum (9%) Pons (9%) Other cortical areas (25%)
Normal cerebral blood flow? (in mL/100g of brain/min)
At what CBF does the brain exhibit physiologic changes in a stroke?
Normal CBF 40-60 mL/100g of brain/min
When CBF drops below 15-18 mL/100g of brain/min, brain loses electrical activity, although membrane integrity and function remain intact.
When CBF <10mL/100g brain/min, membrane failure occurs → ↑ extracellular K and ↑ intracellular Ca → cell death
Territories of the brain supplied by anterior circulation
80% of the brain: optic nerve, retina, fronto-parietal and anterior-temporal lobes.
Supples basal and medial aspects of cerebral hemispheres, extends to anterior 2/3 of the parietal lobe.
Branches of middle cerebral artery and territories they supply?
MCA supplies:
Lenticulostriate branches: putamen, part of anterior limb of internal capsule, lentiform nucleus, external capsule
Main cortical branches: lateral surfaces of cerebral cortex of anterior portion of frontal lobe to posterolateral occipital lobe
Territories of the brain supplied by posterior circulation?
20% of the brain: brainstem, cerebellum, thalamus, auditory/vestibular centers of the ear, medial temporal lobe, visual occipital cortex
Timing for progression of anterior vs posterior circulation strokes?
Anterior circulation strokes may progress w/in 1st 24h.
Posterior strokes may progress for up to 3d.
Where is the lesion?
Pt presenting with: altered mentation, impaired judgement and insight. Presence of primitive grasp/suck reflexes. Paralysis/hypesthesia of lower limb opposite side of lesion. Leg weakness > arm weakness>
Anterior cerebral artery.
Where is the lesion?
Pt with marked motor/sensory disturbance contralateral to the lesion, worse in face/arm than in leg. Motor disturbance almost always accompanied by numbness in same region.
Blindness ipsilateral to lesion.
Middle cerebral artery
Pt with agnosia and aphasia. Where is the lesion?
Middle cerebral artery of DOMINANT hemisphere
Pt unable to process sensory input, such as speech, and thus fails to understand verbal communication.
Wernicke’s aphasia (receptive aphasia).
*** Localizes to dominant hemisphere (usually left)
Pt unable to communicate verbally in an effective way, even though understanding may be intact.
Broca’s aphasia (expressive aphasia).
*** Localizes to dominant hemisphere (usually left)
Characteristics of posterior circulation strokes?
CN deficits
Cerebellar involvement
Neurosensory tracts
Reticular activating system - mediates consciousness
Visual agnosia (unable to recognize seen objects) and alexia (unable to understand written word)
Visual neglect
*** CROSSED DEFICITS - motor on 1 side and sensory on the other
Signs of vertebrobasilar artery insufficiency?
Vertigo, syncope, diplopia, visual field deficits, weakness, paralysis, dysarthria, dysphagia, spasticity, ataxia, nystagmus
Pt with intracranial hemorrhage with perihematomal edema out of proportion to hemorrhage. What are you concerned for?
Consider hemorrhage into a metastasis or primary tumor.
Findings on CT imaging with early ischemic stroke?
Hyperdense artery sign (acute thrombus in a vessel), sulcal effacement, loss of insular ribbon, loss of gray-white interface, mass effect, acute hypodensity.
*** Only acute hypodensity and mass effect have been shown to be associated with ↑ risk of ICH after fibrinolysis.
BP goals for acute ischemic stroke?
What are BP parameters for tPA?
Withhold antihypertensives unless SBP >220, DBP >120, or MAP > 130.
Goal BP for tPA: <185/110
BP meds in acute stroke?
Labetalol 10-20mg IVP, may repeat x1
Nicardipine infusion 5mg/h, titrate up by 2.5mg/h at 5-15min intervals
Dosing for tPA?
0.9mg/kg IV, max 90mg.
10% given as bolus, followed by 90% by infusion over 60min.
Timing for tPA?
Recommended within 3h of symptom onset.
Inclusion criteria for extending time window from 3h-4.5h: diagnosis of ischemic stroke causing measurable neurological deficit. (Exclusions: >80yo, NIHSS >25, oral AC regardless of INR, h/o DM PLUS prior ischemic cva)
*** American stroke association recommends given w/in 60min of arrival.
BP goals with intracranial hemorrhage?
BP Goal: <160-180 systolic
OR
MAP < 130mmHg
Reversal agents for coagulopathy in intracerebral hemorrhage?
Warfarin?
Dabigatran?
Apixaban/Rivaroxaban?
Warfarin: Vitamin K 10mg IV or SQ, FFP 2-4U, PCC (KCentra) 25-50U/kg depending on INR
Dabigatran: Idarucizumab
Apixaban/Rivaroxaban: PCC (Kcentra)
Post-thrombolytic symptomatic intracranial hemorrhage treatment?
Cryoprecipitate (6-8U) for thrombolytic-associated ICH that occurs shortly (0-3h) after alteplase administration. Later ICH (3h-days) is unlikely to be associated with persistent coagulopathy, because fibrinogen depletion following alteplase administration is transient.
Medical therapies aimed at decreasing ICP in patients with intracerebral hemorrhage? (3)
- Hyperventilation - can be temporizing measure pending more definitive treatment
- Mannitol - removes fluid from intracranial compartment, thereby reducing cerebral edema
- Hypertonic saline (3% or 23.4%) as alternative or in combination with mannitol.
Other experimental modalities: barbiturate coma and hypothermia.
What type of seizure?
Abnormal neuronal firing within a confined population of neurons in 1 brain hemisphere, and clinical manifestations tend to reflect the area of electrical activity.
Partial seizures
What type of seizure?
Focal seizure with preserved mental status
Simple focal seizure
What type of seizure?
Focal seizure with some degree of impaired consciousness
Complex focal seizure
What type of seizure?
Abnormal neuro firing throughout BOTH brain hemispheres, always involves alteration of consciousness.
Generalized seizure
What type of seizure?
Starts as focal seizure, progresses to generalized event
Secondarily generalized seizure