Published 23 March 2009, doi:10.1136/bmj.a2343
Cite this as: BMJ 2009;338:a2343

Practice

10-Minute Consultation

Transient ischaemic attack

¹ Glan Clwyd Hospital, Rhyl, Denbighshire LL18 5UJ, ² The Laurels Surgery, Flint, Flintshire CH6 5AF

A 64 year old man comes to your surgery five days after an episode of visual loss in his left eye, followed by right sided weakness and speech disturbance lasting 10 minutes. He has made a complete recovery and has driven himself to the surgery to ask whether he can return to work.

What issues you should cover

General points

• Transient ischaemic attack (TIA) is a sudden onset focal neurological deficit that resolves completely within 24 hours.
  
• Amaurosis fugax, an embolic form of a TIA in the carotid territory, is painless transient monocular blindness, described as a curtain, shade, or mist descending over the eye.
  
• The diagnosis of a TIA is based entirely on history rather than brain imaging.
  
• The risk of a recurrent event after a TIA is highest in the first month (risk of 8-10% at seven days and 11-15% at 30 days).
  

Assessing symptoms
Onset—Symptoms are sudden in TIA, as in acute stroke. Insidious onset of symptoms is unlikely to be a TIA.

Intensity— Symptoms of a TIA are maximal at onset. Gradual progression of symptoms would point to a different pathology, such as migraine, demyelination, or a tumour. Even though recurrent events could follow a TIA, multiple and intermittent symptoms are atypical and should raise the possibility of demyelination or a tumour.

Focal symptoms—Focal neurological symptoms are the classic sign of a TIA. Carotid territory symptoms include amaurosis fugax, contralateral weakness or numbness, dysphasia, and hemianopia. Vertebrobasilar territory symptoms include ataxia, vertigo, dysarthria, diplopia, hemianopia, and bilateral visual loss. Dizziness, lightheadedness, or vertigo occurring in isolation is rare in a TIA.

Global dysfunction—Loss of consciousness (syncope) is not a TIA. Deviation of the angle of the mouth and slumping towards one side seen during syncope could easily be mistaken for a TIA. Isolated memory loss is due to transient global amnesia, which is not a TIA.

Duration—Most TIAs last 5-15 minutes. Symptoms lasting for more than an hour are usually classed as minor strokes. Symptoms lasting less than 30 seconds are unlikely to be due to a TIA.

Recognisable pattern—Symptoms corresponding to a recognised neurological territory are supportive of a TIA. Combination of symptoms such as dysphasia, face and arm weakness (as determined by the face, arm, and speech test (FAST)) has a higher specificity in the diagnosis. Other common combinations are hemiparesis and hemisensory loss with or without hemianopia, ataxic hemiparesis and diplopia, dysarthria, vertigo, and ataxia.

Headache—Even though headache can occur during a TIA, severe headache or eye pain is not a feature of a TIA.

What you should do

Examination—Include a check of his pulse for irregular rhythm, measure his blood pressure, listen to heart sounds, and undertake a neurological examination to detect any residual signs.

Investigations—Take a full blood count and measure urea and electrolytes, fasting blood glucose, and total cholesterol. All patients with carotid circulation TIA who are fit for surgical intervention should have urgent carotid dopplers done either through primary care or secondary care, according to local guidelines.

Prognostic score—The "ABCD2" score, which is based on age (60 years: 1 point), blood pressure (140/90 mm Hg: 1 point), clinical features (unilateral weakness: 2 points; or speech disturbance: 1 point), duration ( 60 minutes: 2 points; 10-59 minutes: 1 point), and presence of diabetes mellitus (1 point), should be used to identify people who are at high risk of stroke (score 4).

Referral—All patients with a TIA should be referred to secondary care as soon as possible. The UK National Institute for Health and Clinical Excellence (NICE) recommends that patients with an ABCD2 score of 4 should be assessed and investigated within 24 hours.

Antithrombotic treatment—All patients with a TIA should be started on aspirin 300 mg immediately. Long term antithrombotic treatment should include combination of aspirin (75 mg once daily) and modified release dipyridamole (200 mg twice a day). Clopidogrel (75 mg once daily) should be used only if the patient is intolerant to aspirin. The combination of clopidogrel with aspirin or dipyridamole is not recommended. If he is already taking aspirin, dipyridamole should be added, and there is no reason to switch to clopidogrel routinely. In patients with atrial fibrillation, warfarin should be begun only after imaging. If a patient is already on warfarin, check his international normalised ratio and seek advice from secondary care regarding urgent brain imaging.

Other secondary preventive measures—Advise smoking cessation, regular exercise, cutting salt and alcohol intake, blood pressure control according to national guidelines, and screening for diabetes and hypercholesterolaemia (consider a statin if the total cholesterol is >3.5 mmol/l or LDL cholesterol is >2.5 mmol/l).

Driving—He should not drive for a month after a TIA.

Excluding a diagnosis of transient ischaemic attack Symptoms that don’t suggest TIA Loss of consciousness Acute confusion Seizure Loss of memory Isolated dizziness, lightheadedness, or vertigo Gradual progression of symptoms Multiple recurrent symptoms Severe headache Mimics of TIA Migraine Partial seizure Syncope Vestibular disorders Neuropathy and radiculopathy Ocular disorders Hypoglycaemia Tumours of the central nervous system

Further reading and resources National Institute for Health and Clinical Excellence. Stroke: the diagnosis and acute management of stroke and transient ischaemic attacks. (Clinical guideline 68, July 2008.) www.nice.org.uk/CG68 Royal College of Physicians. National clinical guidelines for stroke. 3rd edn. London: RCP, 2008 Johnston SC, Rothwell PM, Nguyen-Huynh MN, Giles MF, Elkins JS, Bernstein AL, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007;369:283-92 Easton JD. Redefining transient ischaemic attack. Neurology 2004;62(suppl 6):S1-34 Stroke Association (www.stroke.org.uk) has information for patients

Cite this as: BMJ 2009;338:a2343

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This is part of a series of occasional articles on common problems in primary care. The BMJ welcomes contributions from GPs

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

(Accepted 10 July 2007)

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