Transient ischaemic attack

What it is

A transient ischemic attack is a brief, reversible episode of focal neurologic dysfunction without acute infarction, the deficits being due to focal ischemia. It is ischemia without infarction.

On duration the pages differ, and both numbers are used. One puts it at no more than 24 hours with a normal diffusion-weighted MRI; a second says the majority resolve in less than 15 minutes; a third defines it as neurologic deficits that resolve within 24 hours of onset. Although the symptoms often resolve, many patients will have evidence of infarction on CT or MRI.

How it presents

The onset is sudden and the deficits are focal and neurological, the same opening as a stroke; what parts the two at the bedside is that in a transient attack the symptoms have resolved, while ongoing symptoms make stroke probable.

The written case is a 78-year-old man who comes to the ED complaining of left arm weakness that started 10 minutes ago in the clinic, with a history of hypertension and diabetes and no similar symptoms in the past, feeling well otherwise; his BP is 157/85 mm Hg, HR 87, temperature 98.8 and RR 14; his neurologic examination is unremarkable and he states that his left arm is no longer weak. The whole diagnosis is in the two facts that the deficit was focal and that it has gone.

Two other settings are worth naming. In continuous dizziness or vertigo that is spontaneous, the HINTS examination is what is done, and a central etiology, meaning stroke or transient ischemic attack, is the answer when there is no saccade, when the nystagmus is dominantly vertical, torsional or gaze-evoked bidirectional, and when the test of skew is abnormal. In syncope, a vertebrobasilar attack is one of the neurologic cerebrovascular causes, and a rare one, and it comes with focal neuro deficits, diplopia, vertigo and ataxia.

Fibromuscular dysplasia is a named cause to hold: 90% women in adults, with internal carotid artery stenosis presenting as recurrent headache, pulsatile tinnitus, transient ischemic attack and stroke, and renal artery stenosis presenting as secondary hypertension and flank pain, with a subauricular systolic bruit and an abdominal bruit on examination.