Stroke & TIA Flashcards
What is a ‘stroke’?
Sudden loss of brain function resulting from an interference with blood supply to the brain with persistence of symptoms >24 hrs or with evidence of infarction on neuroimaging.
What % of strokes are hemorrhagic vs ischemic?
80% ischemic, 20% hemorrhagic.
What is a TIA?
Transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischemia, without acute infarction. Most last <1 hr. Longer episode (>10 min) associated with increased risk for early stroke.
What symptoms are suggestive of stroke? (public education).
Weakness/numbness in arm, leg face.
Speech disturbance (loss of speech, difficulty understanding speech).
Visual disturbance, especially in one eye or diplopia.
Severe HA (concerning for SAH or ICH).
Vertigo or loss of balance, especially with above symptoms.
Key features predictive of Dx of stroke (4)
1) LOC: normal or slightly decreased in stroke (significant decrease suggestive of hemorrhage, mimic or severe brain stem stroke).
2) Onset: abrupt with symptoms often maximal at onset.
3) Focal symptoms that fit single vascular territory
4) HA: No HA or mild HA in ischemic stroke (pain more suggestive of hemorrhage or dissection).
What features are suggestive of an alternative diagnosis (not a stroke)?
Decreased LOC, gradual onset, fever, fluctuating signs, no focal signs.
Name a DDx for stroke mimics (12)
1) Seizure: aura, focal deficits, post-ictal phase, often decreased LOC, tend to have + rather than -ve symptoms (e.g. paraesthesias rather than numbness).
2) Migraine: more gradual onset over many minutes.
3) Transient global amnesia: pure amnesia, no focal signs, lasts 24 hrs.
4) Syncope: sudden LOC, rapid recovery.
5) Hypoglycemia: usually more generalized features.
6) Metabolic encephalopathy/OD/sepsis: non-focal, predominant confusion, slurred speech, decreased LOC w/o other focal findings.
7) Tumor: usually not sudden onset.
8) Encephalitis: Confusion and fever are typical.
9) Subdural hematoma: less sudden onset.
10) Bell’s palsy: Weak frontalis muscle (as opposed to preserved frontalis function)
11) Peripheral vertigo: isolated vertigo typically not a TIA/stroke
12) Conversion d/o: neuro findings not in a vascular distribution.
What is the most important question on history when assessing a potential stroke?
When did the symptoms begin
What investigations should you order for potential stroke?
Basic labs (CBC, chem, coag, glucose).
ECG +/- telemetry (ID afib).
Neuroimaging (r/o ICH and stroke mimics)
- non-contrast CT head initially (followed by contrast), ideally including imaging of carotid and vertebral arteries.
If imaging of carotids/vertebrals not done w/ initial CT head, get imaging by doppler US or CTA within 24 hrs.
Why is early vascular imaging required for TIA/stroke patients?
If carotid artery stenosis present, then pt considered ‘symptomatic’ from their carotid artery stenosis. This means should get endarterectomy and outcomes are better if done within 2 weeks of stroke.
NNT for severe stenosis (>70%) is 6 to prevent 1 stroke in 5 years. NNT symptomatic moderate stenosis (50-69%) is 22.
Thus, if >50% stenosis, refer urgently to neuro or vascular surgeon.
What are the key components of early stroke mgmt
ABCs: consider intubation for severe strokes.
Position: use minimal elevation of head if necessary to decrease aspiration (keep head of bed flat if possible).
NPO.
NS to keep euvolemic.
Cardiac monitoring: 24-72 hrs cardiac monitoring to look for afib.
O2: keep sat >=94%.
Antiplt therapy (after 24 hrs).
HTN: Do NOT tx aggressively in first 24 hrs as may result in under-perfusion.
Hyperthermia: tx with cooling and antipyretics and search for cause.
Tx hyperglycemia (5-10) as associated with worse outcomes.
Tx cardiovascular RF (smoking, etc).
How should HTN be managed in the context of stroke
Do NOT aggressively tx in first 24 hrs.
If >220/120, consider lowering by 10-20% in first 24 hrs.
If >185/110 and considering tPA, BP will need to be lowered before tPA can be given.
Describe the utility of antiplatelet therapy in the context of stroke
Reduces further vascular events by ~25%.
ASA: After hemorrhage r/o by CT, loading dose of 160 -325 mg followed by 81 long term.
Plavix: Loading dose of 300mg then 75 mg daily.
**I believe typically, wait 24 hrs for hemorrhagic stroke/transformation to be r/o, then use DUAL antiplt for period of time then change to monotherapy.
What thrombolytic should you give for ischemic stroke and when should it be given?
Alteplase (tPA, IV tissue plasminogen activator).
Should be given within 4.5 hrs of onset of symptoms but benefit is likely better if given sooner (ideally within 90 min).
What are the exclusion criteria for thrombolytics?
1) Hx ICH (any time)
2) Stroke or serious head/spine trauma w/in 3 mo
3) Major surgery in past 2 wks
4) Elevated PTT or INR or plt <100,000
5) Any other condition that could increase bleeding.
6) BG <2.7 or >22.2
7) persistently elevated BP >185/110
