Transcript 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
Face Arm Speech Test (FAST) screening
for paramedics/nurses
Harbison. Stroke 2003;34;71-76;
‘Acute brain attack with’ +ve FAST screen?
Clinical assessment
CT Scan
Stroke: Infarct,
intracerebral bleed,
SAH
Non-stroke pathology
Conditions that mimic acute
stroke
miscellaneous
SAH
TGA
vertigo
MS
syncope/presyncope
3.1%
dementia
psychogenic
migraine
confusional state
3.6%
SDH
tumour
PN palsy
toxic/metabolic
18.2%
seizures
0.0%
5.0%
10.0%
15.0%
20.0%
% of all stroke mimics (n=670)
25.0%
30.0%
Acute brain attack
If NO evidence of ‘mimic, e.g.:
fits/migraine
Hypo/hyperglycaemia
Other obvious metabolic cause
DO CT
CT Scan
Stroke: Infarct,
intracerebral bleed,
SAH
Non-stroke pathology
Subdural, tumour
Non-stroke: bilateral subdural haematoma
Acute brain attack
Exclude: fits/migraine
Hypo-hyperglycaemia
Other metabolic causes
CT Scan
CT Normal or evidence of
acute ischaemic stroke
Non-stroke pathology:
Subdural, tumour, etc
Problems of clinical diagnosis
within 6 hours of onset
Do you need a neurologist?
• Approximately 75% of conditions mimicking stroke are
neurological
How 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 normal
If 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!
2hrs ago right hemiparesis:
thrombolyse?
CT Normal
MRI DWI abnormal
-but DWI not widely available
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 nonstroke 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 score
To ‘likely not eligible’
• prior cognitive impairment
• LOC early
• seizure
• can walk now ( too mild)
Can you diagnose ‘acute ischaemic
stroke suitable for thrombolysis’ without
DWI MR? Yes, if:
• 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