Transient Ischemic Attack (TIA)

🔍 When to Suspect

Sudden onset of focal neurological symptoms (e.g., unilateral weakness/numbness, speech disturbance, visual loss) which have completely resolved within 24 hours

From the full topic in The Ocean Library: Transient Ischemic Attack (TIA)

🧭 When to suspect

A transient ischaemic attack is a transient episode of focal neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia, without acute infarction. Symptoms come on suddenly, are maximal at onset, and resolve completely – classically within minutes to an hour and, by definition, within 24 hours. True TIAs rarely last longer than an hour; the modern tissue-based definition rests on the absence of infarction on diffusion-weighted MRI.

The clinical importance is simple: a TIA is a warning of imminent stroke. The risk of stroke is highest in the first hours to days after the event, and urgent assessment with prompt secondary prevention substantially reduces that early risk. Every suspected TIA is therefore a medical emergency, even when the patient feels completely recovered.

Two skills matter in primary care: recognise it (a sudden, focal, fully-resolved deficit) and act fast (aspirin plus urgent referral); and distinguish it from mimics – up to half of suspected TIAs prove to be something else – without ever letting that uncertainty delay referral. Crucially, NICE advises against using ABCD2 or any risk score to decide urgency: treat every suspected TIA as high risk.

Suggests TIA	Suggests a mimic – think again
• Sudden onset, maximal at the start, then complete resolution	• Gradual onset or a spreading “march” of symptoms (migraine)
• “Negative” deficits – loss of function: unilateral weakness or numbness, dysphasia	• “Positive” phenomena – visual scintillations, limb jerking, spreading tingling (migraine or seizure)
• Amaurosis fugax – a curtain descending over one eye	• Isolated symptoms alone – dizziness, syncope or confusion in isolation are rarely a TIA
• Symptoms fitting a single vascular territory (carotid or vertebrobasilar)	• Preceding aura or headache, or post-event confusion (migraine, seizure)

Source: NICE NG128 · National Clinical Guideline for Stroke (UK and Ireland)

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