greek.doctor

2B. Transient ischemic attack

The classic definition of transient ischaemic attack is that there are symptoms of stroke which fully resolve within 24 hours.

However, some strokes only cause transient symptoms. For this reason, there’s another, newer definition as well, that TIA is defined as transient neurological dysfunction caused by ischaemia without infarction. New definition requires MRI with DWI sequence for diagnosis. If there is infarction, the diagnosis is stroke instead. However, this definition is not yet widely used.

The risk factors for TIA are the same as for ischaemic stroke, and TIA is a strong risk factor for stroke in the following days.

Clinical features

The symptoms of TIA are the same as the symptoms of stroke, so check out the stroke symptom topics 16A and 26A. For TIA, the symptoms per definition resolve within 24 hours, but in most cases they last only a few minutes, so that the symptoms have passed before the patient reaches the hospital.

Diagnosis and evaluation

It’s important to investigate TIA as if it was stroke (although not as acutely), because patients with TIA can develop stroke very soon.

Head MRI, carotid ultrasound, ECG, and echocardiography are essential in the evaluation of TIA, and to exclude disorders which can mimic TIA. ECG and echo can identify cardiac sources of embolism. Carotid ultrasound can identify carotid stenosis as source of thrombosis or embolism.

The ABCD2 score is used to estimate risk of stroke in the next two days. It can also be a help to guide whether patient should be hospitalised or not. Each factor gives 1 or 2 points.

  • Age > 60 years – 1 point
  • Blood pressure – systolic > 140 mmHg or diastolic > 90 mmHg – 1 point
  • Clinical features
    • Speech impairment – 1 point
    • Unilateral weakness – 2 points
  • Duration
    • 10 – 59 minutes – 1 point
    • > 60 minutes – 2 points
  • Diabetes – 1 point
  • < 3 points: low risk
  • > 7 points: high risk

Treatment

Aspirin is usually started ASAP, sometimes with an added P2Y inhibitor. It’s important to begin secondary prevention for stroke immediately, like hypertension, dyslipidaemia, smoking cessation, etc.