4 Stroke, part 1 Flashcards
Definition of “Time of symptom onset”
The last known time when the patient’s condition was at their baseline (i.e., “last known well” time)
*Not the time a patient was discovered with symptoms”
Not the time of awakening (if symptoms were noted upon awakening)
Top priority in stroke assessment
Assessment of airway, breathing, and circulation
What is Todd’s paralysis?
Seizure/postictal paralysis
Transient paralysis following a seizure, which typically disappears quickly
Can be confused with a transient ischemic attack
Note that seizures can be secondary to a cerebrovascular accident.
Blood glucose considerations in some of the prehospital stroke scales
Los Angeles Preshospital Stroke Screen
60- 400 mg/dL
Melbourne Ambulance Stroke Screen
50-400 mg/dL
Most widely used scale for documenting the severity of a stroke
National Institute of Health Stroke Scale (NIHSS)
- weighted toward the detection of anterior circulation strokes
- has a bias toward detection of left hemisphere strokes
Important scoring rules for proper use of the NIHSS
- Score what you see, not what you think
- Score the first response, not the best response (except in item 9, best language)
- Do not coach
Components of the NIHSS
1a Level of consciousness [LOC] (3)
1b LOC questions (2)
1c LOC commands (2)
—-
2 Best gaze (2)
3 Visual (3)
4 Facial Palsy (3)
—-
5a Motor arm, left (4)
5b Motor arm, right (4)
6a Motor leg, left (4)
6b Motor leg, right (4)
—-
7 Limb ataxia (2)
8 Sensory (2)
9 Best language (3)
10 Dysarthria (2)
11 Extinction and inattention (2)
Interpretation of the NIHSS score
0 - No stroke symptoms
1-4 - minor stroke
5-15 - moderate stroke
16-20 - moderate-to-severe stroke
21-42 - severe stroke
Remarks on anterior cerebral artery (ACA) infarction
Causes contralateral sensory and motor symptoms in lower extremity, with sparing of the hands and face
A left-sided ACA lesion is tyipcally associated with
akinetic mutism and transcortical motor aphasia (a nonfluent aphasia with greatly reduced spontaneous speech, but with retained autidory comprehension and repetition ability)
a right-sided ACA lesion is typically assocaited with
confusion and motor hemineglect
most commonly involved vessel in stroke
Middle cerebral artery (MCA)
Remarks on dominant hemisphere
In right-handed patients and in up to 80% of left-handed patients, the left hemisphere is dominant.
If the dominant hemisphere is involved, aphasia (receptive, expressive, or both) is often present.
If the nondominant hemisphere is involved, this may occur
inattention, neglect, extinction, dysarthria without aphasia, and constructional apraxia
Classic symptoms of posterior cerebral artery (PCA) stroke
(distal posterior circulation stroke)
Ataxia
Nystagmus
Altered mental status
Vertigo
This may indicate a brainstem lesion
Crossed neurologic deficits (e.g., ipsilateral cranial nerve deficits with contralateral motor weakness)
Remarks on basilar artery occlusion
(middle posterior circulation stroke)
most common presenting signs/symptoms are
- unilateral weakness
- cranial nerve VII signs
- dysarthria
- Babsinki sign
- oculomotor signs
- dizziness
- Horner’s syndrome
- Locked-in syndrome (rarely)
Basilar artery occlusions have high risk of death and poor outcomes
Remarks on locked-in syndrome
Can occur rarely in basilar artery strokes
Occrs with bilateral pyramidal tract lesions in the ventral pons
Characterized by complete muscle paralysis except for upward gaze and blinking
Remarks on proximal posterior circulation stroke
(vertebrobasilar infarction)
may present with unilateral cranial nerve V symptoms
Horner’s syndrome
Remarks on cerebellar infarction
- Up to 25% of noncontrasted head CT is unremarkable. Hence, obtain an emergent diffusion-weighted MRI when this diagnosis is suspected
- Rapid deterioration may occur due to increased brainstem pressure from cerebellar edema. Serially examine for gaze palsy and altered mental status.
- Obtain early neurosurgical consultation for patients with cerebellar infarction for possible emergency posterior fossa decompression
Remarks on lacunar infarction
- Lacunar infarcts are pure motor or sensory deficits caused by infarction of small penetrating arteries
- Commonly associated with chronic hypertension and incrasing age
- Prognosis is generally considered more favorable than for other stroke syndromes
Remarks on cervical artery dissection
- Consists of carotid and vertebral artery dissection
- Major cause of stroke in young adults and the middle-aged
- A history of * neck trauma in the days to weeks prior to presentation is a prominent risk factor
* (the trauma is usually minor, such as manipulative thearpy of the neck or sport-related trauma)*
Cervical artery dissections’ typical first symptom
unilateral *headache (68%), neck pain (39%), or face pain (10%)
*headache in carotid artery dissection is most commonly frontotemporal and may mimic SAH (thunderclap)
*headache in vertebral artery dissetion is typically occipital
Diagnostic modalities of choice for suspected cervical artery dissections
CT/CT angiography and MRI/magnetic resonance angiography
Treatment of cervical artery dissection
Treated similarly to any other stroke patient (i.e., *thrombolysis, antiplatelet/anticoagulation)
**no increased incidence of harm*
Remarks on SAH
- Typically characterized by severe occipital or nuchal thunderclap headache
- May be associated with activities with a Valsalva maneuver, such as defecation, sexual activity, weight lifting, or coughing, at stroke onset
