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Aids to Diagnosis - TIA

The following information (from Stroke: a practical guide to management, Warlow et al) may help the non-specialist identify and manage TIA's. You can read more about TIAs on our Stroke pages. 

What is a TIA?

A focal neurological or monocular event

Motor

  • Weakness of one side
  • Simultaneous bilateral weakness
  • Dysphagia
  • Ataxia

Speech

  • Difficulty understanding or expressing words
  • Difficulty reading or writing
  • Difficulty calculating

Sensory

  • Altered feeling on one side

Visual

  • Loss of vision in one eye
  • Loss of vision of half or quarter of the visual field (ie both eyes)
  • Bilateral blindness
  • Double vision

Vestibular

  • A spinning sensation

Cognitive

  • Difficulty dressing
  • Visual, spatial, perceptual dysfunction
  • Amnesia

 

2. Quality

Symptoms and signs are usually "negative" ie loss of function.  They can be "positive" ie pins and needles, shaking, scintillations in vision, but this is rare.

3.Time Course

The onset is abrupt, without intensification or spread. Maximal deficit usually occurs in a few seconds.  The offset is usually within 1 hour. It is always, by definition, within 24 hours.

4. Associated Symptoms

TIA’s occur without warning.  Headache may occur.  Loss of consciousness is only rarely due to TIA.

5. Neurological signs

Neurological signs (eg reflex assymetry, upgoing plantar) may be present during the attack.  There may also be signs or previous cerebrovascular disease.

6. Frequency of attacks

TIA’s recur but frequent stereotyped attacks raises the possibility of partial seizure or hypoglycaemic episodes.

7. Risk factors

Patients with TIA usually have risk factors for cardio and cerebro-vascular disease.

What is not a TIA?

The following are unlikely to be due to TIA:

  • Generalised weakness or sensory disturbance
  • Light-headedness
  • Faintness
  • Blackouts
  • Incontinence
  • Confusion.

The following, if isolated, are also unusual: Vertigo, tinnitus, dysphagia, dysarthria, diplopia, ataxia 

What if it is a TIA?

Basic Investigations 

  • Urinalysis, FBC, Viscosity, U&E, Lipids, Glucose, VDRL, ECG, CXR
  • Carotid ultrasound (if carotid distribution TIA and patient would be surgical candidate)
  • CT head scan

 

Secondary prevention

Advised secondary prevention and numbers needed to treat (to prevent one further event per year)

Intervention Number needed to treat
Stopped smoking 43
Warfarin, if patient in AF 12
Aspirin 100
Antihypertensive agent (whatever the BP) 27
Statin (whatever the lipids) 20
Carotid endartectomy (if>70% stenosis in symptomatic carotid) 6
Addition of clopidogrel to aspirin 100

 

Hospital service

TIA is now considered a medical emergency.  The ABCD score below gives the risk of stroke in some clinical scenarios.  Daily TIA clinics are held at both Gloucester Royal and Cheltenham General Hospitals.   Referral is by referral form, fax (08454222092 -CGH, 08454226326 - GRH) or letter.  These clinics give access to opinion, investigation and treatment.  If the risk of stroke, as calculated below, is in the higher group emergency admission may be appropriate.

 

ABCD Scoring - giving risk of stroke within two days of TIA

Age >60 1 point
BP >/= 140/90 1 point
Clinical features: Unilateral weakness 2 points
Clinical features: Speech impaired without weakness 1 point
Duration >/= 60 minutes 2 points
Duration 10-59 minutes 1 point
Diabetes 1 point

 

Score Risk
6-7 8.1%
4-5 4.1%
3 or below 1.0%