Define stroke mimics and understand the importance of recognizing a mimic in the inpatient setting

Define stroke mimics and understand the importance of recognizing a mimic in the inpatient setting

• Define stroke mimics and understand the importance of recognizing a mimic in the inpatient setting

• Discuss common mimics, including their pathophysiology and manifestations

• Distinguish between an ischemic stroke and a mimic

• Cases

A condition that causes signs and symptoms similar to that of an acute stroke (ie focal neurologic deficit)

• A condition that causes signs and symptoms similar to that of an acute stroke (ie focal neurologic deficit)

• 19% of >400 pts presenting with suspected stroke were mimics in a 1995 study1 and 31% of >300 pts were mimics in a 2006 study by Hand 2

Younger, female, fewer stroke risk factors3

• Younger, female, fewer stroke risk factors3

• Global aphasia with minimal to no paresis4

• Milder baseline stroke severity (median admission NIHSS of 4 in mimics compared to 8 in ischemic stroke)5

• Other studies have found no distinction in gender/age/risk factors

Postictal deficits (Todd paralysis) (21%)1

• Postictal deficits (Todd paralysis) (21%)1

• Sepsis (13%)1

• Metabolic (hypoglycemia, ETOH intox, hyponatremia, hepatic encephalopathy, etc) (11%)1

• Migraine with aura

• Mass lesions

• Peripheral vestibulopathy

• Conversion reaction

Typically characterized by unilateral, pulsating pain a/w n/v and/or photo/phonophobia

• Typically characterized by unilateral, pulsating pain a/w n/v and/or photo/phonophobia

• Aura occurs in 20%

• Lifetime prevalence: women 43%, men 18%6

• Only 37% of Americans with chronic migraine (≥15 HA/m, ≥4 hrs/d) are employed full time6

• Common triggers: diet, sleep disturbance, head trauma, meds, hormones, dehydration

Once thought to be primarily vascular

• Once thought to be primarily vascular

• A complex sequence of changes occur

• Cortical spreading depression
• Trigeminovascular system
• Converge in trigeminal nucleus caudalis
• Fibers ascend to cortical/subcortical sites, incl thalamus
• Trigeminal ganglion stimulation-> vasoactive neuropeptides (substance P, CGRP)->inflammation (vasodilation, protein extravasation)
• Sensitization

Most common manifestation is visual

• Most common manifestation is visual

• Enlarging scotoma with ‘shimmering’ edge
• Stars, dots, shapes, wavy lines, visual distortions (phosphenes, fortification spectra)

• Sensory Aura

• Pins and needles sensation, numbness
• Cheiro-oral paresthesias

• Motor Aura

• Uncommon, may present with hemiparesis/plegia

• Speech disturbance

Dysphasic speech disturbance

• Dysphasic speech disturbance

• Reporter Serene Branson on-air

Aura of weakness 5 min – 24 hrs but can last days; never the only type of aura during an attack

• Aura of weakness 5 min – 24 hrs but can last days; never the only type of aura during an attack

• Visual->sensory-> motor->aphasic-> brainstem

• Weakness typically moves from hand->arm->face

• Can switch sides b/t, during attacks; may be b/l in FHM

• Rare - est prevalence is 0.01 % 7

• Avg age of onset 12 to 17 years

Mode of onset key? 52 of 68 pts had slow progression of sx vs sudden onset often seen in ischemic events8

• Mode of onset key? 52 of 68 pts had slow progression of sx vs sudden onset often seen in ischemic events8

• On MRI – may see restricted diffusion in long-lasting migraine, but should completely resolve; +ADC in stroke, NOT in migraine

2012 study looked at 1850 consecutive suspected strokes9

• 2012 study looked at 1850 consecutive suspected strokes9

• 1% (20) ultimately dx w/migraine with aura

• Hypoperfusion found in 70%

• >1 vascular territory affected in ALL
• PCA area affected in visual aura; MCA area with motor or speech disturbance
• Complete resolution at follow-up

Episode of neurologic dysfunction with abnormal neuronal firing presenting with changes in:

• Episode of neurologic dysfunction with abnormal neuronal firing presenting with changes in:

• motor control
• sensory perception
• behavior
• autonomic function10

• Epilepsy - name given to recurrent, spontaneous seizures that are suggestive of ongoing altered electrical activity

Disruption in the normal balance b/t excitatory and inhibitory currents in the brain

• Disruption in the normal balance b/t excitatory and inhibitory currents in the brain

• Mediated via 2 types of ion channels

• Voltage gated – activated by changes in membrane potential. Na/Ca are excitatory; K/Cl are inhibitory
• Ligand gated – activated by NTs. Glutamate is excitatory; GABA is inhibitory

• Glial cells help regulate ion/NT concentrations

Anything that alters the balance b/t excitation and inhibition: trauma, infection, drugs, etc...

• Anything that alters the balance b/t excitation and inhibition: trauma, infection, drugs, etc...

• Recurrent seizures -> decreased threshold for additional seizures

Partial seizures arise from localized area of the brain; can spread to involve the whole brain (secondary generalization)

• Partial seizures arise from localized area of the brain; can spread to involve the whole brain (secondary generalization)

• Generalized seizures arise from both hemispheres simultaneously

Postictal phenomenon->hemiparesis/plegia contralateral to seizure focus

• Postictal phenomenon->hemiparesis/plegia contralateral to seizure focus

• May include visual disturbance, rarely hemineglect

• Results from complex partial or generalized seizures

• Occurs in 13% of seizure cases11

• Can last b/t 0.5 and 36 hrs

Robert Bentley Todd (1809-1860)

• Robert Bentley Todd (1809-1860)

• Clinician, anatomist, pathologist, physiologist
• Introduced the terms afferent and efferent
• Founded King's College Hospital – London
• First to formulate an electrical theory of epilepsy

“Epileptic hemiplegia” - he stated that:

• “Epileptic hemiplegia” - he stated that:

• 'A paralytic state remains sometimes after the epileptic convulsion....particularly the case when the convulsion has affected only one side or one limb...will remain paralytic for some hours or even days...but it will ultimately perfectly recover.'

• Attributed this to 'depression or exhaustion' induced by the excessive discharge of cells12

Gowers (1845-1915) a British neurologist, felt that inhibition of motor centers, not exhaustion, led to postictal paralysis

• Gowers (1845-1915) a British neurologist, felt that inhibition of motor centers, not exhaustion, led to postictal paralysis

• Yarnell (1975) and Kimura (1998) demonstrated hyperperfusion in pts w/postictal paralysis; ?vasomotor, metabolic changes

• Multifactorial – NT depletion, desensitization, altered local cerebral blood flow, inhibition?

Well known phenomenon of hemiplegia and aphasia in hypoglycemia (<45 mg/dl in studies)14

• Well known phenomenon of hemiplegia and aphasia in hypoglycemia (<45 mg/dl in studies)14

• Pathophysiology unclear
• Diminished LOC may or may not be present
• Can resolve immediately w/IV glucose, or take hrs

• Hyponatremia, uremia, hepatic encephalopathy, etc...may also mimic stroke

• PMH important, as are appropriate lab studies; may see asterixis on exam

Includes primary tumors, abscesses, metastatic lesions

• Includes primary tumors, abscesses, metastatic lesions

• Symptoms are typically progressive but onset may be abrupt, possibly due to intralesional hemorrhage, hydrocephalus or seizure from edema/mass effect15

• History and imaging help make diagnosis

Risk of symptomatic ICH about 6% in tPA treated pts16 but….

• Risk of symptomatic ICH about 6% in tPA treated pts16 but….

• No inc risk in mimics and no need for hesitation if c/w acute stroke and a tPA candidate
• 2010 retrospective study of >500 consecutive ischemic stroke admits given tPA; 10.4% mimics - no sICH5

• May delay appropriate treatments (ie delay in migraine specific therapy or initiation of AED in seizure)

3 types of bias: 17

• 3 types of bias: 17

• Anchoring – placing too much emphasis on a single clinical finding (ie hemiparesis)
• Availability – multiple exposures to a presentation
• Premature closure – forming initial dx and not considering other differentials

• Employ effective data gathering (hx, PE, labs)

• Review available data, form a differential

86 yo F h/o HTN, DM, left frontal meningioma resection 25 yrs ago to ED with sudden expressive aphasia while on the phone with her daughter. No weakness or vision change and complete resolution in 3 min.

• 86 yo F h/o HTN, DM, left frontal meningioma resection 25 yrs ago to ED with sudden expressive aphasia while on the phone with her daughter. No weakness or vision change and complete resolution in 3 min.

• VS: Wt 137, BP 191/69, HR 71 RR 20
• HCT showed L hypodensity ?prior surgery; CTA h/n read as ?subacute L frontal infarct
• CTA findings did not correlate with presentation; final dx was TIA
• Vascular risk factors addressed, f/u HCT in 3wks

2 weeks later, pt returns to ED with progressive word finding difficulty, clumsiness, unsteadiness

• 2 weeks later, pt returns to ED with progressive word finding difficulty, clumsiness, unsteadiness

• Marked expressive aphasia > receptive aphasia on exam
• HCT: inc size of L hypodensity, incl vasogenic edema, mild subfalcine herniation
• MRI: Heterogeneously enhancing partially cystic mass in the L frontal lobe with vasogenic edema extending to the body of the left lateral ventricle. Mild rightward bowing of the interhemispheric falx
• Decadron, LEV started per Neurosurgery; pt’s speech improved, and bx is pending

Mrs. Jackson calls EMS because she woke up in the morning to find her 35-year-old husband lying in bed confused, exhibiting a left-side facial droop and not moving his left arm and leg. EMS arrived and see the patient lying in bed confused with slurred speech, left-side facial droop and left side-paralysis. They administer oxygen (O2) via non-rebreather mask at 12 L/min and start an IV of normal saline TKO and transported to the stroke center on the ECG monitor. En route, the crew checks his blood glucose serum level; it’s 35 mg/dL. They administer an amp (50 cc's) of dextrose 50% D50 in water, and the symptoms cleared. At the hospital, the emergency department (ED) physician consults with the neurology department, and an MRI is performed and found to be negative for stroke. http://www.jems.com/article/patient-care/identifying-diseases-mimic-str

• Mrs. Jackson calls EMS because she woke up in the morning to find her 35-year-old husband lying in bed confused, exhibiting a left-side facial droop and not moving his left arm and leg. EMS arrived and see the patient lying in bed confused with slurred speech, left-side facial droop and left side-paralysis. They administer oxygen (O2) via non-rebreather mask at 12 L/min and start an IV of normal saline TKO and transported to the stroke center on the ECG monitor. En route, the crew checks his blood glucose serum level; it’s 35 mg/dL. They administer an amp (50 cc's) of dextrose 50% D50 in water, and the symptoms cleared. At the hospital, the emergency department (ED) physician consults with the neurology department, and an MRI is performed and found to be negative for stroke. http://www.jems.com/article/patient-care/identifying-diseases-mimic-str

74 yo M h/o CAD s/p CABG, HLD, DM2, R PCA territory stroke to ED with R hemiparesis, slurred speech after syncopal episode at Ophtho office. NIHSS 6 in ED (2 pts from old stroke)

• 74 yo M h/o CAD s/p CABG, HLD, DM2, R PCA territory stroke to ED with R hemiparesis, slurred speech after syncopal episode at Ophtho office. NIHSS 6 in ED (2 pts from old stroke)

• VS: Wt BP 189/90 (dec to 160 systolic with 5 mg labetalol), HR 92 RR 18
• No early infarct signs on HCT
• tPA given - shortly after, RUE/RLE weakness resolved; slight R facial droop/dysarthia from prior stroke

Additional hx:

• Additional hx:

• During VF test, pt suddenly stared into space, unresponsive for 1.5 min; confused, pale

• MRI/A - no evidence of acute stroke; chronic strokes, severe intracranial atherosclerotic disease

• Normal EEG

• Trileptal 150 mg BID for CPS

46 yo F h/o HTN, migraine with/without aura (scotoma) since birth of her child 10 yrs ago to ED with slow progression over min of L hand->arm->face->numbness while shoveling snow. Gradual resolution over 10 min ->mild apical HA x few hrs

• 46 yo F h/o HTN, migraine with/without aura (scotoma) since birth of her child 10 yrs ago to ED with slow progression over min of L hand->arm->face->numbness while shoveling snow. Gradual resolution over 10 min ->mild apical HA x few hrs

• Other hx:

• Few mos ago:
• episode of nausea, lightheadedness, unknowingly speaking native language x 10s at work ->dull apical HA
• ‘Lost time’ briefly at work. Outpatient 24 hr EEG was normal
• VS: Wt 149 lbs, BP 120/80, HR 94, RR 18
• Neurologic exam non-focal

18 hrs after sx resolution, MRI brain showed +DWI R posterior frontal cortex; no clear ADC correlate…

• 18 hrs after sx resolution, MRI brain showed +DWI R posterior frontal cortex; no clear ADC correlate…

Ordered MRA along with limited cut repeat MRI: persistent +DWI, now with +ADC = migraine assoc infarct

• Ordered MRA along with limited cut repeat MRI: persistent +DWI, now with +ADC = migraine assoc infarct

• D/c on nortriptyline for prevention

• Few mos later: At work, wave of nausea, speaking native language, witnessed lip smacking, lost time x1 min

• c/w CPS; earlier events also likely seizure
• Switched to TPX->Depakote
• Currently no further events

MRI with DWI

• MRI with DWI

Many conditions share clinical features with TIA/stroke

• Many conditions share clinical features with TIA/stroke

• Thorough hx, PE, labs, judicious use of imaging can help differentiate

• Use of tPA shown to be safe in mimics

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• Zinkstok S, Engelter S, Gensicke H, et al. Safety of thrombolysis in stroke mimcs. Stroke. 2013; 44: 1080-1084

• Winkler D, Fluri F, Fuhr P, et al. Thrombolysis in stroke mimics: Frequency, clinical characteristics and outcome. Stroke. 2009; 40: 1522-1525

• Tsivgoulis G, Alexandrov A, Chang J, et al. Safety and outcomes of intravenous thrombolysis in stroke mimics. Stroke. 2011; 42: 1771-1774

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