Acute Stroke Diagnosis: science and art

Clinical diagnosis in the acute phase of stroke –

quite a challenge!

Peter Sandercock

Edinburgh

11 am. Wife notices husband speech a bit odd and right hand clumsy.

Is it a stroke?

Clinical diagnosis in the hyperacute phase (< 6hrs)

• Need to be quick: ‘Time is brain’

• Need to triage in A&E as potential thrombolysis / IST 3 candidate if:– known time of onset– onset less than 5 hrs ago– definite focal neurological deficit still present (use

FAST or LAPSS for screening)

• NIHSS and OCSP classification if FAST +ve

Harbison. Stroke 2003;34;71-76;

Face Arm Speech Test (FAST) screening for paramedics/nurses

‘Acute brain attack with’ +ve FAST screen?

CT Scan Non-stroke pathology

Stroke: Infarct, intracerebral bleed, SAH

Clinical assessment

Conditions that mimic acute stroke

3.1%

3.6%

18.2%

0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0%

seizures

toxic/metabolic

PN palsy

tumour

SDH

confusional state

migraine

psychogenic

dementia

syncope/presyncope

MS

vertigo

TGA

SAH

miscellaneous

% of all stroke mimics (n=670)

Acute brain attack

If NO evidence of ‘mimic, e.g.: fits/migraine

Hypo/hyperglycaemia

Other obvious metabolic cause

DO CT

CT Scan Non-stroke pathologySubdural, tumour

Stroke: Infarct, intracerebral bleed, SAH

Non-stroke: bilateral subdural haematoma

Acute brain attack

Exclude: fits/migraine

Hypo-hyperglycaemia

Other metabolic causes

CT Scan Non-stroke pathology:Subdural, tumour, etc

CT Normal or evidence of acute ischaemic stroke

Do you need a neurologist?• Approximately 75% of conditions mimicking stroke are

neurologicalHow many of these can be identified by CT?• ~15% of non-stroke disorders (eg subdural) found by CT• rest diagnosed clinically/with other tests• CT < 6hrs of ischaemic stroke often normalIf CT is normal • Often need stroke specialist or neurologist to confirm clinical

diagnosis of stroke before thrombolysis:• avoid thrombolysis for migraine, focal epilepsy, ‘functional

weakness’, ischaemic deficit after subarachnoid haemorrhage!

Problems of clinical diagnosis within 6 hours of onset

CT NormalMRI DWI abnormal

-but DWI not widely available

2hrs ago right hemiparesis: thrombolyse?

Edinburgh ‘brain attack’ study

Aim • Identify the ‘brain attack’ patients most likely to

have acute cerebral ischaemia, potentially for thrombolysis

Patients• 350 admissions (336 patients)• Age: 76.3 yrs (67 - 83)• Source of referral to stroke team: A&E triage in

92%• Time from onset to A&E: 4.7 hrs (2 - 14)

Hand PJ. Stroke 2006; 37: 769-775.

Primary analysis• ‘Thrombolysis eligible brain attacks’

(n=241) = definite stroke, probable stroke, definite TIA

• Mimics (n=109) = definite non-stroke, all possible stroke/TIA with a plausible non-stroke explanation

Pointers to ‘rt-PA/ist3 eligible:’ past history

Pointer to ‘more likely NOT for thrombolysis/IST3’

Pointer to ‘more likely eligible’

Pointers to ‘rt-PA/ist3 eligible:’ History of this event

NIHSS training website

http://asa.trainingcampus.net/uas/modules/trees/windex.aspx

Note: works best with a high-speed (broadband) connection!

Clinical pointers: summary

To ‘likely eligible for thrombolysis/ist3’• Known time of onset • Abnormal vascular signs (AF, PVD)• Unilateral neurological signs • Can assign an OCSP classification• Increasing NIH scoreTo ‘likely not eligible’• prior cognitive impairment• LOC early • seizure• can walk now ( too mild)

• The time of onset of stroke symptoms is known precisely

• You have an experienced stroke physician/stroke neurologist able to see the patient urgently in A&E or at CT scan room

• Urgent non-contrast CT scan is interpreted by someone with expertise in acute stroke CT

• -> MRI not essential; its place in routine acute stroke care yet to be determined

Can you diagnose ‘acute ischaemic stroke suitable for thrombolysis’ without

DWI MR? Yes, if: