gp lecture programme 3 february 2010 dr stephen louw stroke physician rvi newcastle upon tyne

GP Lecture Programme3 February 2010

Dr Stephen Louw

Stroke Physician

RVI Newcastle upon Tyne

Population Relative Risk for Stroke

• High ABCD2 score: 8% chance in next 2 days• AF 5 – 17x (if >2 risk factors, 18% stroke p.y.)• Hypertension 3-4• Alcohol 4 • Migraine: 2.16• IHD 2-4• CCF 2-4• Diabetes 2-4 • Smoking 1.5-2.9• Hyperlipidaemia – uncertain as a sole risk• PFO 26% of general population have a PFO.

Commonest TIAs

Middle Cerebral Artery Territory• Total or partial anterior Circulation TIA

– Hemiplegia/hemianaeasthesia

– Homonymous hemi-anopia

– Cortical problem: dysphasia/visual or sensory neglect

• Lacunar-type: pure motor or sensory or mixed• Amaurosis fugax• Post circulation (difficult to diagnose)

Middle Cerebral Artery TerritoryThe focus of ABCD2 scale

Validation and refinement of scores to predict very early stroke risk after TIA: Johnston SC, Rothwell PM et al. Lancet 2007. Jan. 27:369:283-92.

ABCD2

Score

2-day risk 7-day risk 90-day risk

5 4.1% 5.9 9.8

7 8.1% 11.7 17.8

Middle Cerebral Artery TerritoryThe focus of ABCD2 scale

The focus of investigations in hospital:

• Identify patients with critical internal carotid artery stenosis

• Rapid referral for carotid endarterectomy

• CEA– Benefits: reduces stroke risk by 50%– Risks: immediate death or stroke: 2 – 3%

Carotid Endarterectomy European Carotid Surgery Trialists’ Collaboration Group (ECTST) The Lancet

1998;351:1379-87 CLASSIC PAPER

• Patients with recent TIA or stroke and 70 – 99% carotid stenosis clearly benefit in terms of stroke prevention. Confirmed NASCET (1991)

• Pts with <70% stenosis were harmed by CEA.• NNT (surgery) 14 pts to prevent a major

ipsilateral carotid territory stroke over the next 5 years.

Limb shaking TIA

• 1-2 min duration• Usually severe carotid

stenosis• Often good surgical

candidates• Differential diagnosis• Partial seizure• Tremor

Capsular warning TIAGeoffrey Donnan (Australia) Neurology 1993;43:957

• 4.5% of TIAs • Ischemia due to

haemodynamic phenomena in a diseased, single, small penetrating vessel

• Leads to lacunar infarct and involved a single penetrating vessel

Posterior Circulation TIA

POCS TIA is more likely if:

         true diplopia

         DDK

         past pointing

         Dysarthria

Posterior Circulation TIA

Low predictive rate for POCS TIA if:

Isolated features of• ‘Dizziness’,• unsteadiness,• vertigo or• ‘ataxia’.

Transient Global Amnesia

• Sudden onset of disorientation – amnesia for immediate events

• Speech intact

• No other focal neurology

• Resolves within minutes

Unusual types of Migraine

Ocular migraine• Transient loss of

vision• Usually with headache

Basilar type migraine• Affects both sides• Rarely motor signs• Aura may include:

– Blindness– Vertigo– Diplopia– Dysarthria– Ataxia

Stroke

Rapid recognition of symptoms and diagnosis

Reproduced with permission from The Stroke Association

– Use the FAST tool to screen for stroke or TIA outside hospital

How accurate is FAST?Diagnostic Accuracy of Stroke Referrals…J Harbison, O Hossain, D Jenkinson, J Davis, SJ Louw, GA Ford.Stroke 2003;34:71-76

• 487 patients; 356 stroke/TIA• FAST used by ambulance paramedics

– 23% = non-stroke– 46% admitted within 3 hours

• Primary Care Doctors– 29% = non-stroke– 14% admitted within 3 hours

• ER– 29% = non-stroke

Limitations of FAST

• Does not take pre-existing disability into account

• Low sensitivity for posterior circulation strokes: – occipital lobes (vision)– cerebellum (often no weakness)– brain stem (sensory deficit, cranial nerve

lesions)

TIME IS BRAINTime window: stroke to needle 4.5 hrs

Suspectedstroke?

Within 3.5

hours?

Call 999: blue light patient into stroke unit

Time-windows for thrombolysis

• A limit (not a ‘target’)

• Anterior circulation strokes– 4.5 hours

Reason for time-limit

• For every 3 patients we thrombolyse, one will have a significantly less marked level of impairment.

but…..• One in 30 patients we thrombolyse, will be

harmed (including death) due to symptomatic bleeding (including intracranial).

r-TPA in Newcastle upon Tyne

• In total 4 major bleeds – 2 deaths

PH 2

Time-windows for thrombolysis

• A limit (not a ‘target’)

• Anterior circulation strokes– 4.5 hours

• Anterior circulation strokes in very young people – 6 hours (intra-arterial thrombolysis)

Time-windows for thrombolysis

• A limit (not a ‘target’)• Anterior circulation strokes

– 4.5 hours

• Anterior circulation strokes in very young people – 6 hours (intra-arterial thrombolysis)

• Posterior circulation strokes– 12 hours (intra-arterial thrombolysis)

Fast track system: Newcastle

• All cases blue lighted by ambulance to Acute Medical Unit (AMU)

• Ambulance paramedics notify before setting off from patient’s home

• AMU SpR/Senior Nurse phones Stroke Consultant and Notifies CT scan personnel

Cases NOT for 999 referral

• Low likelihood of benefit from rTPA– poor pre-stroke functional level

– dementia, Nursing Home

– uncertain onset time (e.g. “woke up with stroke”)

– seizure

• High risk of bleeding complix from rTPA– surgery/major trauma within the last 2 weeks

– on warfarin, bleeding tendency

Common Stroke Mimics

• Seizure – Todd’s paralysis

• Cardiovascular collapse

• Migraine

• Labyrinthine disorders

• Infection- related delirium (“?dysphasia with no other focal neurological deficit”)

Improving stroke services in the North East

• Primary prevention– FATS 5 guidelines– Anticoagulation for AF– Hypertension

• Secondary prevention: Spotting TIAs

• Rapid referral of acute stroke

• Enhanced rehabilitation services