1. GP Update TIA and mimics
Kath Pasco
Oct 2015

2. Outline Why is it important to diagnose TIA?
Challenges of the TIA presentation
Common mimics
Case discussion
Secondary prevention
Outline

3. True TIA=high risk stroke
Essential to identify true vascular event due to very high early risk of ischaemic stroke
15-20% patients with stroke report preceding TIA
True TIA=high risk stroke

4. Stroke following TIA Risk of stroke following a TIA 10% at 7 days
Express study 2007 (Rothwell et al) identified that investigating and treating high risk patients with TIA could reduce those that go on to have full stroke by 80%
Stroke following TIA

5. Definite diagnosis can be a challenge
Broad differential
Symptoms are transient
No definitive test
Relies on patient account
Inter observer agreement of TIA between stroke trained and non neurologist is poor
Up to 60% patients referred = mimic
Migraine/seizure/syncope
Definite diagnosis can be a challenge

6. Temporary focal neurological symptoms (cerebral, retinal or rarely spinal ischaemia)
24 hour duration outdated
Majority last under 30 mins
Clinical diagnosis
Accurate history interpretation skills
TIA

7. Locally decreased blood flow to the brain causing focal symptoms
Embolism (from heart, proximal vessels, extra or intracranial usually affected by atherosclerosis
In situ occlusion of small perforating arteries
Resolution occurs spontaneously with lysis and passage of thrombus or collateral compensation
NB cerebral hypoperfusion due to critical stenosis stereotyped and related to upright posture
Mechanism

8. Screening of referrals?
Recent discussion at UKSF confirms different practice
Aim to see patients with TIA in 24 hours
Challenges in practice
Usefulness of ABCD score? Limitations?
Brain and vessel imaging same day?
Imaging before or after assessment?
Screening of referrals?

9. Even transient symptoms can show evidence of tissue ischaemia in dwi MRI
Can allow risk modification
Confirm vascular aetiology
Likelihood dwi+ increases with symptom duration
Role of brain imaging

10. TIA should mimic stroke syndromes ie arterial territory
Some patterns identify territory
ie aphasia = left, monocular visual loss = carotid ischaemia
Hemianopia = occipital , diplopia = brainstem ischaemia
Patients presenting with very transient single syndromes eg isolated vertigo, dysarthria need to consider mimics before diagnosing TIA
Clinical features

11. Clinical features Abrupt onset
Age and other demographics – ? increase probability of a cerebrovascular event
Nature of symptoms – ‘negative’ vs ‘positive’
Onset and progression
Duration
Precipitating factors
Associated features – headache, loss of awareness during or after
Clinical features

12. Rare in young individuals without vascular risk factors (hypertension, IHD, DM, smoking, haem disease)
Pregnancy= transient neurological symptoms often migraine
Seizure and syncope can occur at any age, underlying mechanism will be different
When TIA is less likely

13. Clinical features Positive ‘excess’ CNS electrical discharges
Visual – flashing lights, zigzag shapes, lines, objects
Somatosensory – pain, paraesthesia
Motor – jerking limb movements
Negative
loss/reduction of CNS function
loss of vision, power, hearing, sensation
Clinical features

14. Clinical features Seizures and migraine often start with +ve
TIAs typically –ve (but may develop +ve)
Seizures only rarely cause paresis from the outset (but may develop post ictal) - sequence of symptom onset is relevant
Clinical features

15. Speech Dysarthia Dysphasia
Did they know what words they were trying to say?
Were the words you heard the right ones, albeit slurred
Isolated complete and brief speech arrest (recurrent and stereotyped) probably focal seizure
Speech

16. Symptom onset and progression
TIA - onset abrupt with negative symptoms, all occurring at same time and gradually improve
Migraine aura - onset progresses slowly over minutes to tens of minutes, positive symptoms followed by negative
Eg paraesthesia hand, then to arm to shoulder followed by numbness
Eye – aura across field then field defect
Seizure - onset progress in seconds, single domain. Associated with LOC, recurrent episodes and stereotyped.
Symptom onset and progression

17. Symptom Duration Migraine – 10-30mins TIA - < 1 hour
Seizures – 5 mins
Syncope – seconds
TIAs occur over days to weeks, ‘crescendo’
If longer time period will be seizure, syncope, migraine
Symptom Duration

18. Precipitating factors/Associated symptoms
Seizure – hyperventilation, sepsis, altered etoh intake,
Haemodynamic TIA (jerking) may occur on sudden standing, after taking BP meds, following large meal or hot bath
BPPV – head turning
Global features unusual for TIA
Remember mechanism
Tongue biting, muscle pains after event – seizure
Vomiting after migraine
Nausea, sweating, pallor, need to urinate or defecate common post syncope
Precipitating factors/Associated symptoms

19. Common mimics Migraine with aura Transient Global Amnesia Seizure
Amyloid spells
Structural brain lesions
Haemodynamic TIA
Subdural
(Demyelination)
Common mimics

20. Migraine with aura Spectrum of severity
Acephalic migraine – aura with minimal headache
Aura reflects cortical spreading depression
Hence spreading onset
Visual sx – zigzag (geometric), ‘like looking through heat haze’, kaleidoscope
Migraine with aura

21. Migraine with aura Can include sensory, motor or speech disturbances
Hemiplegic migraine (familial and sporadic types)
Headache can occur in TIA and stroke, often if have history migraine
Concept of Migrainous infarction controversial
‘Secondary migraine’
Migraine with aura

22. Transient Global Amnesia
Temporary loss of anterograde episodic memory
Usually aged over age 50
Not uncommon to have vascular risk factors
Symptoms last over several hours
Gap in memory persists
Procedural memory intact, repetition common
Consider seizure – lip smacking, limb posturing
Transient epileptic amnesia TEA antero- and retrograde amnesia, other cognitive functions intact, recurrent episodes
Transient Global Amnesia

23. Transient Global Amnesia
Episodes rare
Does not increase stroke risk
Functional imaging suggests hypoperfusion mesial temporal lobes
TIA rarely affects memory – posterior circulation bilateral medial temporal lobe structures
So if memory involved likely to be a mimic
Transient Global Amnesia

24. Amyloid spells Cortical leptomeningeal white matter perforators (1mm)
Amyloid deposition within superficial arteries impairs venous drainage. Blood leaks.
Transient focal neurological episode, positive symptoms
? Seizure activity or cortical spreading haemorrhage
MRI gradient sequence characteristic sign
May be indicator of future ICH
Cortical superficial siderosis
Amyloid spells

25. Structural brain lesions
Meningiomas
? Associated seizures
Gradual onset, stuttering
Structural brain lesions

26. Haemodynamic TIA Limb shaking = hemispheric hypoperfusion Posture BP
Recurrent
Haemodynamic TIA

27. After diagnosis Reflect on presentation Reassure – mimic
Evaluate vascular health
Consider role of medication
Further investigations?
Driving
Functioning
After diagnosis

28. Secondary prevention Express trial Aspirin and clopidogrel
Aggressive BP management
Statin
Treatment from clinic
BP monitoring
Secondary prevention

29. Best medical therapy Optimise vascular health
Target known risk factors
Review unknown risk factors
AF/PAF – immediate anticoagulation
NOAC vs warfarin/clexane
Issue immediate treatment
Best medical therapy

30. Next steps post Express?
What agent is responsible for risk reduction seen?
Benefit from aspirin use in short term but does not appear sustained after 90 days
? Role of aspirin with ‘funny turn’
Bleeding risk increases with age
? Rotate use of aspirin and clopidogrel in 3 month cycles to maintain benefit seen
Next steps post Express?

31. Timing of carotid surgery
When to operate post TIA?
(When to operate post stroke?)
Robust pathway for referral
Urgent imaging and second modality
NTN %, % (variables)
RR less as time passes
Timing of carotid surgery

32. End of clinic Often no FU required
GP and patient to manage vascular health
Commence secondary prevention
Where diagnosis unclear offer further review
End of clinic