Stroke Mimics and Differential Diagnosis ANNA Stroke...

Louise Weir

Stroke Nurse Practitioner

Candidate- The Royal Melbourne

Hospital

Stroke Mimics and

Differential Diagnosis

ANNA Stroke Seminar 2010

RMH Comprehensive Stroke Centre

Clinical assessment

Aims

(1) Is it a stroke? (What is the diagnosis)

(2) What part of the brain is affected?

(3) Is it a haemorrhage or an infarct?

(4) What caused this stroke? (Can we prevent a

further stroke)

(5) What are this patient‟s problems?

+

(6) What can we do to treat this patient?

(1) Is it a stroke?

(ii) The nature of the event

• onset: usually sudden• course: maximal at onset, occasionally evolves

over days • were symptoms focal: focal vs general• “negative”: loss of function• associated symptoms: headache - 25% infarcts,

seizures & vomiting

What are Focal Neurological Symptoms?

• Weakness of face/ arm/ leg on one side

• Sensory disturbance face/ arm/ leg on one side of the body (NB –Caution if this is the only symptom & Caution if sensory symptoms only last minutes)

• Amaurosis Fugax (transient monocular blindness)

• Language disorder (aphasia)

• Homonymous hemianopia (visual field loss)

• Sudden bilateral blindness

• Diplopia (NB –Caution if this is the only symptom)

• Dysarthria (NB –Caution if this is the only symptom)

Symptoms unlikely to be TIA or Stroke

i.e. Non- focal symptoms

• Light headedness/ faintness

• „Blackouts‟ with altered or loss of consciousness or fainting

• Generalized weakness and/or generalized sensory disturbance

• Incontinence of urine or faeces

• Episode of confusion

• Drop attacks

Symptoms if isolated unlikely to indicate

TIA or Stroke

• A spinning sensation

• Vertigo only

• Ringing in ears

• Difficulty swallowing

• Slurred speech

• Double vision

• Loss of balance

Two clinical scenarios

1. The patient with resolved symptoms

• A completed TIA

• A pseudo/mimic

2. The patient with symptoms: ‘Brain

Attack’

• More relevant when seeing patient acutely

Difficulties in TIA diagnosis

• There are many causes of transient symptoms

which are not due to vascular disease

• Do not make the diagnosis until you have an

accurate account of the patients symptoms.

• Ask a witness for details as patients may often

forget because symptoms were short,

confusion was present, or there was a loss of

consciousness

Brain Attack: persistent symptoms

• An open label, not a completed diagnosis

• Implies there are differentials

• Is stroke easy to diagnose?

– Literature: ~20% of referrals are incorrect

– Prospective study of consecutive patients

presenting to hospital with brain attack

– 350 presentations:

241 strokes (69%)

109 mimics (31%)

Peter Hand et al. Stroke 2006; 37: 769-775

Conditions that mimic stroke: 350 consecutive

presentations Mimics presenting:

Condition Total Number (%)† Within 6 hrs

‡ After 6 hrs

‡

Seizure 23 (21.1%) 18 (29.0%) 5 (10.6%)

Sepsis 14 (12.8%) 6 (9.7%) 8 (17.0%)

Toxic / metabolic 12 (11.0%) 6 (9.7%) 6 (12.8%)

Space occupying lesion§ 10 (9.2%) 3 (4.8%) 7 (14.9%)

Syncope / presyncope 10 (9.2%) 9 (14.5%) 1 (2.1%)

Acute confusional state 7 (6.4%) 3 (4.8%) 4 (8.5%)

Vestibular dysfunction 7 (6.4%) 3 (4.8%) 4 (8.5%)

Acute mononeuropathy 6 (5.5%) 4 (6.5%) 2 (4.3%)

Functional/medically

unexplained symptoms

6 (5.5%) 4 (6.5%) 2 (4.3%)

Dementia 4 (3.7%) 2 (3.2%) 2 (4.3%)

Migraine 3 (2.8%) 2 (3.2%) 2 (4.3%)

Spinal cord lesion¶ 3 (2.8%) - (0%) 3 (6.4%)

Other? 3 (3.7%) 2 (3.2%) 1 (2.1%)

Total 109 (100%) 62 (100%) 47 (100%)


Conditions that mimic stroke Systematic review of literature (n=1,265 mimics)

0.0% 2.5% 5.0% 7.5% 10.0% 12.5% 15.0% 17.5% 20.0%

seizures

toxic/metabolic

sequelae of old stroke

SOL

syncope/presyncope

vertigo

migraine

psychogenic

dementia

PN palsy

meningitis/encephalitis

wernickes/alcohol

miscellaneous

% of all stroke mimics (n=1,265)

Peter Hand et al. 2000.

The miscellaneous group

• Cardiac cause (ischaemia, heart failure etc.) 24

• Spinal cord lesion 13

• Multiple sclerosis 12

• Transient global amnesia 11

• Parkinson‟s disease 8

• Subarachnoid haemorrhage 6

• Trauma 4

• Hypertensive encephalopathy 3

• Myasthenia gravis 3

• Acute confusional state 2

• Aortic dissection 2

• Herpes encephalitis 2

• Motor neuron disease 2

• Parasthesia of unknown cause 2

• Vertebral artery dissection 1

• Friedreich‟s ataxia 1

• Multiple systems atrophy 1

• Cerebral sarcoidosis 1

• Normal pressure hydrocephalus 1

• Sleep apnoea 1

• Perforated duodenal ulcer 1

• Weakness of unknown cause 1

• Arm stiffness of unknown cause 1

• Arm pain of unknown cause 1

• Sudden death 13

• No details provided 76

• Total 193


Stroke mimics

• 42% of pts had previous stroke

– Around half had no residual symptoms

– Many might have an abnormal scan

• 26% of pts had cognitive impairment

• 75% of mimics were neurological conditions

– Many of these would have normal scans

• This highlights the importance of the

neurologist and or Nurse Practitioner in acute

assessment


Reliability of clinical assessment

• Reliability is the likelihood of 2 observers

finding the same thing (i.e. agreement)

– Accuracy depends on validity & reliability

• Reliability sub-study

– 98 non-consecutive patients

– 4 different observers, blind to history

• Kappa – measure of agreement

– Allows for agreement expected by chance

– κ <0.2 poor agreement; 0.21– 0.40 = fair; 0.41– 0.60 =

moderate; 0.61– 0.80 = good; 0.81– 1.00 = excellent

agreement


I t e m K v a l u e 9 5 % C I C r u d e A g r e e m e n t*

V a s c u l a r R i s k F a c t o r s :

H y p e r t e n s i o n 0 . 4 7 0 . 3 2 – 0 . 6 2 6 5 / 9 7 ( 6 7 % )

S m o k e r w i t h i n 1 2 m o n t h s 0 . 6 9 0 . 5 5 – 0 . 8 3 8 1 / 9 7 ( 8 4 % )

I s c h a e m i c h e a r t d i s e a s e 0 . 6 4 0 . 5 0 – 0 . 7 8 7 7 / 9 7 ( 7 9 % )

A t r i a l f i b r i l l a t i o n 0 . 5 4 0 . 3 8 – 0 . 7 0 7 3 / 9 6 ( 7 6 % )

P e r i p h e r a l v a s c u l a r d i s e a s e 0 . 4 4 0 . 2 7 – 0 . 6 2 6 9 / 9 7 ( 7 1 % )

D i a b e t e s m e l l i t u s 0 . 6 5 0 . 4 5 – 0 . 8 4 7 5 / 8 6 ( 8 7 % )

P a s t h i s t o r y o f a f o c a l n e u r o l o g i c a l d e f i c i t 0 . 5 1 0 . 3 6 – 0 . 6 6 6 9 / 9 8 ( 7 0 % )

H i s t o r y o f t h e p r e s e n t i n g c o m p l a i n t :

A n e x a c t t i m e o f o n s e t c a n b e d e t e r m i n e d 0 . 6 3 0 . 4 7 – 0 . 7 8 8 0 / 9 8 ( 8 2 % )

P a t i e n t w o k e f r o m s l e e p w i t h d e f i c i t 0 . 5 5 0 . 4 0 – 0 . 6 9 7 0 / 9 7 ( 7 2 % )

P a t i e n t c a n r e c a l l w h a t h e / s h e w a s d o i n g a t t i m e o f o n s e t 0 . 3 7 0 . 2 0 – 0 . 5 3 6 0 / 9 7 ( 6 2 % )

I m p r o v e m e n t s i n c e o n s e t 0 . 5 4 0 . 3 9 – 0 . 6 8 6 9 / 9 8 ( 7 0 % )

S y m p t o m s a r e n o w s t a b l e 0 . 5 9 0 . 4 2 – 0 . 7 7 8 1 / 9 8 ( 8 3 % )

P a t i e n t w e l l i n t h e w e e k b e f o r e o n s e t 0 . 4 0 0 . 2 4 – 0 . 5 7 6 4 / 9 8 ( 6 5 % )

A d e f i n i t e h i s t o r y o f f o c a l n e u r o l o g i c a l d e f i c i t 0 . 5 9 0 . 4 2 – 0 . 7 5 7 9 / 9 8 ( 8 1 % )

H e m i a n o p i a / q u a d r a n t a n o p i a 0 . 6 3 0 . 4 7 – 0 . 7 9 7 2 / 8 9 ( 8 1 % )

L o s s o f s p e e c h / l a n g u a g e 0 . 6 4 0 . 5 0 – 0 . 7 7 6 8 / 8 9 ( 7 6 % )

L o s s o f s e n s a t i o n 0 . 6 2 0 . 4 8 – 0 . 7 6 6 8 / 8 9 ( 7 6 % )

L o s s o f p o w e r 0 . 5 9 0 . 4 4 – 0 . 7 5 6 8 / 8 9 ( 7 6 % )

H e a d a c h e 0 . 6 5 0 . 5 1 – 0 . 7 9 7 8 / 9 7 ( 8 0 % )

N e u r o l o g i c a l E x a m i n a t i o n :

T h e p a t i e n t i s a l e r t 0 . 7 0 0 . 5 2 – 0 . 8 9 8 9 / 9 8 ( 9 1 % )

T h e p a t i e n t i s d r o w s y 0 . 7 4 0 . 5 3 – 0 . 9 4 9 2 / 9 8 ( 9 4 % )

T h e p a t i e n t i s u n c o n s c i o u s 1 . 0 0 1 . 0 0 – 1 . 0 0 9 8 / 9 8 ( 1 0 0 % )

T h e p a t i e n t i s c o n f u s e d 0 . 4 5 0 . 2 8 – 0 . 6 2 6 8 / 9 6 ( 7 1 % )

A r m w e a k n e s s 0 . 6 5 0 . 4 9 – 0 . 8 0 8 1 / 9 8 ( 8 3 % )

H a n d w e a k n e s s 0 . 7 2 0 . 5 9 – 0 . 8 6 8 4 / 9 8 ( 8 6 % )

F a c e w e a k n e s s 0 . 5 0 0 . 3 4 – 0 . 6 7 7 3 / 9 8 ( 7 4 % )

L e g w e a k n e s s 0 . 5 7 0 . 4 1 – 0 . 7 3 7 5 / 9 7 ( 7 7 % )

T h e p a t i e n t c o u l d w a l k 0 . 6 2 0 . 4 7 – 0 . 7 6 7 5 / 9 6 ( 7 8 % )

V i s u a l l o s s 0 . 4 6 0 . 2 8 – 0 . 6 4 7 2 / 9 8 ( 7 3 % )

D y s a r t h r i a 0 . 4 1 0 . 2 5 – 0 . 5 8 6 6 / 9 8 ( 6 7 % )

D y s p h a s i a 0 . 6 6 0 . 5 1 – 0 . 8 0 8 1 / 9 8 ( 8 3 % )

S e n s o r y d i s t u r b a n c e 0 . 4 9 0 . 3 4 – 0 . 6 5 6 9 / 9 8 ( 7 0 % )

V i s u a l n e g l e c t 0 . 4 1 0 . 2 5 – 0 . 5 8 6 6 / 9 8 ( 6 7 % )

S e n s o r y n e g l e c t 0 . 5 9 0 . 4 5 – 0 . 7 3 7 4 / 9 8 ( 7 6 % )

O t h e r f o r m o f n e g l e c t 0 . 3 4 0 . 1 6 – 0 . 5 1 6 3 / 9 8 ( 6 4 % )

Timing of symptom onset

• Good reliability for whether there was an exact time of onset (κ=0.63)

• Agreement for:– date, hour and minute in 19/42 (45%)

– date and hour in 11/42 (26%)

– date only in 9/42 (21%)

– complete disagreement for date & time in 3/42 (7%)

• Median difference in onset times for the 23 patients where there was disagreement was 30 minutes (IQR: 10 – 90 minutes)

• Methods to improve timing…


Factors that caused poor reliability

• Experience of clinician:

– Greatest difference for neurological exam

• Clinician confidence:

– Lower reliability when clinician uncertain

• Time since symptom onset:

– Worse in those presenting v.early or late

• Patient factors:

– Much worse when patient had aphasia (not so

bad for confusion or older age)


Clinical features that distinguish between stroke

& mimic

• Stroke predicted by

– exact time of onset

– patient could recall exactly what he/she was doing at

symptom onset

– well in the last week

– definite focal symptoms or signs

• Mimic predicted if

– known history of cognitive impairment

– lost consciousness or had a seizure at onset

– the patient could still walk

– no lateralising symptoms

– examination revealed confusion, signs in other non-vascular

systems and no neurological signs

Stroke vs Mimic:

value of the OCSP classification

n=9

n=4

n=3

n=19

n=41

n=48

n=21

n=11

n=7

0% 20% 40% 60% 80% 100%

Unsure

POCS

LACS

PACS

TACS

Mimic Stroke


Stroke vs Mimic: value of the NIHSS

n=17

n=25

n=9

n=11

n=62 n=130

n=49

n=32

n=38

n=11

0% 20% 40% 60% 80% 100%

NIHSS = 0

NIHSS 1-4

NIHSS 5-10

NIHSS>10

Overall

Mimic Stroke


C lin ic a l I t e m I m p o r t a n c e *

S u g g e s t s t h e l ik e ly

d ia g n o s i s i s :

H is t o r y

D e f in i te h is to r y o f fo c a l n e u r o lo g ic a l s y m p to m s S T R O K E

A n e x a c t o n s e t o f s y m p to m s c a n b e d e te r m in e d S T R O K E

K n o w n c o g n i t iv e im p a i r m e n t M IM I C

E x a m in a t io n

A n y a b n o r m a l v a s c u la r f in d in g s S T R O K E

A n y a b n o r m a l f in d in g s in o th e r s y s te m s M IM I C

E i th e r

N IH S S 1 -4 S T R O K E

N IH S S 5 -1 0 S T R O K E

N IH S S > 1 0 S T R O K E

O r

A r m w e a k n e s s S T R O K E

D ia g n o s t ic f o r m u la t io n

S ig n s c a n b e la te r a l is e d to th e r ig h t / le f t b r a in S T R O K E

S ig n s c a n b e p la c e d in a n O C S P c a te g o r y S T R O K E

Odds Ratios -

Multivariable

Logistic regression:

2.59

2.54

0.44

7.23

3.99

2.03

5.09

0.33

7.21

How to improve accuracy: brain imaging

• Positive findings on the CT confirm the diagnosis of an ischaemic stroke

• Look for early CT signs of infarction

– Loss of tissue density

– Tissue swelling

• Pathology:

– Influx of water into ischaemic cells

– grey matter affected before white matter

Hyperdense MCA

• Occlusion of the MCA

by fresh clot

• May be seen in other

main vessels, distally

or in lenticulostriate

arteries

• frequency varies

• 50% with proven

MCA occlusion don‟t

have the sign

Basal ganglia changes

• Loss of definition

of grey matter -

best seen at

edges of internal

capsule

• Swelling

compresses the

adjacent lateral

ventricle

Cortical surface changes

• „Insular ribbon sign‟

- loss of distinction

between external

capsule and insular

cortex

• Also look for

swelling of cortical

sulci - effacement

(loss of visibility)

Investigations: Imaging• Rationale:

– to exclude (rare) stroke mimics eg SDH

– to distinguish between haemorrhage and

infarct

• Plain CT is the imaging technique of choice

– available, rapid

– reliably differentiates haemorrhage:

blood is white

PICH on CT

• Is always seen

• apparent immediately

• lasts 1 week

• then disappears and

looks like an infarct

Ischaemic stroke on CT• Infarcts seen as areas

of hypodensity

• become more obvious

as time progresses

• small infarcts appear

later than large ones -

75% TACI vs 45% LACI

• overall, 40% strokes

have normal CT

• posterior fossa difficult

MRI in acute stroke

• Advantages:

– much better at defining the anatomy

– shows ischaemic changes earlier, and in a

greater proportion of patients

– diffusion weighted imaging can show ischaemia

within minutes-hours, and differentiate between

old and new lesions

– MRA allows imaging of blood vessels non-

invasively

• Disadvantages:

– expense, time, lack of access to the patient

MRI in acute stroke: an example

A 42 year old man with headache and left hemiparesis

CT brain (3 hours) ? R MCA hypodensity

DWI (24 hrs) obvious R MCA infarct

MRA (24 hrs) dissection R ICA with distal occlusion

Take home messages:

1. Watch out for timing of symptom onset

2. Early ischaemic changes on CT confirm the diagnosis

3. Be aware of red flags for mimics

Distinguishing Between Stroke and Mimic at the Bedside:

The Brain Attack Study

Peter J. Hand, Joseph Kwan, Richard I. Lindley, Martin S. Dennis and Joanna M. Wardlaw.

Stroke 2006;37;769-775; originally published online Feb 16, 2006

DOI: 10.1161/01.STR.0000204041.13466.4c

http://stroke.ahajournals.org/cgi/content/full/37/3/769


Interobserver Agreement for the Bedside Clinical Assessment of Suspected Stroke

Peter J. Hand, Janneke A. Haisma, Joseph Kwan, Richard I. Lindley, Bart Lamont, Martin S. Dennis and Joanna M. Wardlaw

Stroke 2006;37;776-780; originally published online Feb 16, 2006;

DOI: 10.1161/01.STR.0000204042.41695.a1



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