Stroke Mimics
Ahamad Hassan
Consultant Neurologist & Stroke Physician
Leeds Teaching Hospitals
Acute stroke is a treatable medical emergency
All These Interventions
Are time critical !!
Stroke mimic
Popular term to distinguish patients presenting
often acutely with stroke-like symptoms but turn out
to have an alternative diagnosis
Not a disease, but a syndrome
“Get in the way”
Positive diagnosis and specific management
important in this group
Harbison et al Stroke 2003
Sensitivity 79-97%
Specificity 13-88%
BE-FAST (Balance, Eyes, Face, Arm,
Speech, Time)
Reducing the Proportion of Strokes Missed
Using the FAST Mnemonic
Reduced the number of missed strokes to 5-10%Aroor et al Stroke 2017
Stroke Mimics: A systematic Review
PRE HOSPITAL MIXED THROMBOLYSIS
PAPERS 6 37 16
Mean %
mimics
29 25 9
Top Mimic
Diagnosis
Seizures
Migraine
Tumour
Seizures
Migraine
Decompensation
Migraine
Functional
McClelland G et al, PROSPERO 2015
Rosier scale
Used in Emergency room
7 point scoring system
Sensitivity 83-97%
Specificity 18-93%
“Weed out mimics in A+E”
Nor et al , Lancet Neurol 2005
Causes of Stroke Mimics (n=109)
Condition % <6hrs >6hrs
Seizure 21.1 29.0 10.6
Sepsis 12.8 9.7 17.0
Toxic/metabolic 11.0 9.7 12.8
SOL 9.2 4.8 14.9
Syncope 9.2 14.5 2.1
Delirium 6.4 4.8 8.5
Vestibular 6.4 4.8 8.5
Mononeuropathy 5.5 6.5 4.3
Functional 5.5 6.5 4.3
Dementia 3.7 3.2 4.3
Migraine 2.8 3.2 4.3
Hand et al Stroke 2006
Causes of Stroke Mimics (n=109)
Condition % <6hrs >6hrs
Seizure 21.1 29.0 10.6
Sepsis 12.8 9.7 17.0
Toxic/metabolic 11.0 9.7 12.8
SOL 9.2 4.8 14.9
Syncope 9.2 14.5 2.1
Delirium 6.4 4.8 8.5
Vestibular 6.4 4.8 8.5
Mononeuropathy 5.5 6.5 4.3
Functional 5.5 6.5 4.3
Dementia 3.7 3.2 4.3
Migraine 2.8 3.2 4.3
Causes of Stroke Mimics (n=109)
Condition % <6hrs >6hrs
Seizure 21.1 29.0 10.6
Sepsis 12.8 9.7 17.0
Toxic/metabolic 11.0 9.7 12.8
SOL 9.2 4.8 14.9
Syncope 9.2 14.5 2.1
Delirium 6.4 4.8 8.5
Vestibular 6.4 4.8 8.5
Mononeuropathy 5.5 6.5 4.3
Functional 5.5 6.5 4.3
Dementia 3.7 3.2 4.3
Migraine 2.8 3.2 4.3
Safety of TPA in Stroke Mimics
2 large series >500 patients Rx
Stroke Misdiagnosis rate =10-14%
No cases of SICH
90% functionally independent
Message if in doubt Rx !
Chernyshev et al 2010, Tsivgoulis 2011
Recognition tools
Useful for rapid screening
Neurological History/Exam remains essential
Fall back position in ‘grey cases’
Some Tips
NIH stroke scale
Quantify stroke severity in a consistent way
Objectively scoring number/magnitude focal deficits
Predicts lesion size and stroke outcome
Predicts large vessel occlusion
Useful in determining suitability for thrombolysis
? Role in stroke diagnosis
NIH stroke scale
11 item (42 point scale)
Conscious level
Eye movements
Vision
Motor power in limbs/face
Co-ordination
Sensation
Language
Articulation
Inattention
Proportion brain attacks attributable to stroke or mimic
subdivided by NIHSS score
Hand et al Stroke 2006
Logistic regression model for predicting diagnosis of
brain attack
OR 95%CI
Known cognitive impairment 0.33 0.14-0.76
Exact onset determined 2.59 (1.30-5.15)
Definite focal symptoms 7.21 (2.48-20.93)
Abnormal vascular findings 2.54 (1.28-5.07)
NIHSS
1-4 1.92 (0.70-5.23)
5-10 3.14 (1.03-9.65)
>10 7.23 (2.18-24.05)
Signs localise to either left or right 2.03 (0.92-4.46)
OCSP classification possible 5.09 (2.42-10.70)
Symptom Pattern
A
B
C
SEPSIS AND SYNCOPE
Radiology report “Established Lacune”
Unmask old deficits- Toxic effects or
hypoperfusion
Evidence of metabolic/systemic disturbance
Confusion/Delirium may be mistaken for dysphasia
Be wary of aspiration pneumonia in acute stroke
Seizure Disorders
Todd, 1854
“ A paralytic state remains sometime after the epileptic
convulsion. This is more particularly the case when the
convulsion has only affected one side or limb:
That limb or limbs will remain paralytic for several hours or
even days after the cessation of the paroxysm, but will
ultimately recover”
Range of post seizure deficits extended to include,
hemianopia, blindness
aphasia, sensory loss, stupor confusion
Theories......
Todd’s Paresis
Generalised Epilepsy 6%
Focal Epilepsy 13%
Post ictal paralysis variable 11s-36 hours
Established brain injury (often old stroke)
Focal Epilepsies
Ipsilateral motor phenomena 90% clonic shaking (mild)
dystonic posturing
hand automatisms
No Motor Activity 10%Inhibitory seizure
Rolak 1992, Allmetzer 2004
Acute Symptomatic Seizure Following Stroke
5% with stroke present with 1st seizure
Predictors
Haemorrhagic transformation OR= 2.7 vs Ischaemic stroke
PICH OR= 7.2 vs Ischaemic stroke
Cortical features OR= 3.1 vs subcortical
Take home message
1st seizure with hemiparesis, needs urgent CT
If no bleed, no cortical features v.likely to be TODD’S palsy
Beghi et al 2011
Migraine with Aura
Recurrent Disorder
Symptoms have a slow migratory pattern
Coincide with spreading depression
(depolarisation wave spreads across cortex 3-5mm/s)
Visual> Speech> Sensory
Develop over 5-20minutes
Lasts less than 60 minutes
Headache usually present (can be absent), follows
aura.
Other causes ruled out (Headache commonly accompanies stroke)
Hemiplegic Migraine
Can be sporadic/familial
Prevalence = 1/10000
FHM1 (CACNA1A) FHM2 (ATP1A2) FHM3 (SCN1A)
Weakness+ additional aura lasts longer up to 24 hours
Typical march
May have a basilar feel e.g. confusion, ataxia, coma
Occasionally seizures
Attacks sometimes v. prolonged
Triggered by head trauma, catheter angiogram
Interictal problems e.g. progressive ataxia
Migraine with unilateral motor weakness (MUMS)
Onset usually later in 30s (unlike FHM in teens, 20s)
Give way weakness frequently found
Spreading weakness
Weakness improves with treatment of headache/pain
Associated with more diffuse pain
Atypical aura?
Functional
Behavioural response to pain
No difference in anxiety/mood scores
Functional Hemiparesis
HistoryExamination
Investigations
Look for Consistent Inconsistency!
Functional Hemiparesis (Stone et al 2010, case control study, n=107)
Features suggestive in history
High proportion of women but similar in controls
Left hemiparesis not seen more commonly
Multiple symptoms especially pain and fatigue
Other functional problems e.g. IBS, fibromyalgia, CFS
Early hysterectomy (for menorrhagia)
Higher frequency of depression, anxiety disorders
Feel stress is not the cause (vs organic disease)
Less likely to be working
Multiple attacks over long period (+/-normal brain imaging)
Stroke or Mimic?85 year old man
Lives in nursing home, mild dementia
Found slumped by carers in chair, rousable
Twitching right side of mouth
Usually confused (? Slightly worse)
Slurred speech
Mild weakness right arm (NIHSS =5)
Temperature 37.8oC
BM=4.5mmol/l
ROSIER Score
=1
Stroke?
Rosier +
Motor weakness
Abrupt onset
Todd’s Paresis
Low Rosier score
Low NIHSS score
Cognitive impairment
Mild pyrexia
Seizure activity
No bleed on scan
Stroke or Mimic?44 year old man
6 hour history of vomiting and vertigo
Unsteady on feet, coarse nystagmus
photophobic
BP 150/90, BM 6.3
Paramedic FAST Test negative
Anything else you want to ask?
What would you do next?
ROSIER score =0
CT Brain Normal
Sent Home from A+E. Came back next day, drowsy with headache
Has My Dizzy Patient had a Stroke?
Acute Vestibular Syndrome
Syndrome of Dizziness developing acutely, accompanied by nausea, vomiting,
unsteady gait, nystagmus, intolerance to head motion, lasting 24 hours or
more (+/- other focal neurology)
Vestibular neuritis majority
Stroke estimated to account for 25%
Commonly missed in A+E depts
Patients come back in with space occupying cerebellar stroke or progressive
basilar syndromes
I would definitely discuss this patient with my stroke consultant/neurologist
especially if symptoms persisting in ED
HINTS (Kattah et al 2009)
Composite of 3 tests
Head impulse test (Vestibular occular reflex)
Direction changing horizontal nystagmus
Skew deviation
INFARCT
Any 1 of 3 sensitivity 100% Specificity 98%
Better than acute DWI-MRI !!
“Ulnar neuropathy” “Left sided Bell’s palsy”
All hand muscles affected
Brisk reflexes
But subtle ataxia
Abrupt Onset + Good examination skills are also needed
Will a scan help me? (Non contrast CT)
•Widely available,
• IF ICH Yes!
•Often normal in ischaemic CVA
• Early infarct signs confirm clinical suspicion of stroke
• Rarely non stroke neurological mimics seen e.g. SOL
or sub dural haematoma (but often history is “fishy”)
• Rarely clarifies clinical picture, if stroke is uncertain
from outset (advanced imaging more useful)
Stroke or Mimic: Radiology
Hyperdensity MCA Hyperdensity distal MCA Hyperdensity ICA
Excellent inter observer reliability. Low sensitivity, very high specificity 95-100%(If definitely present on the correct side confident that not stroke mimic)
Advanced imaging
Perfusion CT CT-A MR-DWI
66 year old lady found collapsed, GCS=6, temperature 37.5
? Encephalitis
Take Home Messages
Stroke recognition tools allow rapid detection of stroke
with very good sensitivity and specificity
Approx 20% strokes referred for hyperacute treatment
will be mimics
Watch out for stroke chameleons, sometimes hard to
spot
Key discriminators from history and examination can
improve diagnostic accuracy.
Advanced Neuroimaging can play a useful role
In difficult cases
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