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