TIA information for GPs 

How do I diagnose a transient ischaemic attack (TIA)?

Diagnosis of transient ischaemic attack is not straightforward, and if you think that the diagnosis is likely they should be referred, even if you are unsure.  The phrase ‘transient ischaemic attack’ captures the essential clinical features.

Transient.  The patient must have fully recovered before this diagnosis is made.  By convention recovery must have occurred within 24 hours, but most transient ischaemic attacks are much shorter than this.  If the patient still has symptoms the diagnosis may be stroke, but it cannot be TIA.

Ischaemic.  The neurological symptoms need to fit with the territory of an artery.  Do the symptoms that the patient describes sound like a stroke?  Clearly if the patient has weakness down one side, or a loss of language, then we see stroke patients with these symptoms, so the recovered patient may have had a TIA.  On the other hand, we don’t tend to see stroke causing isolated ‘dizziness’, or memory loss, so patients who have had either of these as transient symptoms are highly unlikely to have had a stroke.

Attack.  Of the three words in the phrase transient ischaemic, this is perhaps the most important.  TIAs are almost invariably of sudden onset.  When an artery in the brain blocks, function of the whole area supplied by that artery is lost within a second or two.  Another feature to ask specifically about is evolution of symptoms.  If the neurological impairment spreads gradually from one body part to another or from one modality to another (e.g. visual disturbance followed by tingling in a limb), TIA is very unlikely to be the diagnosis.  Any episode which comes on gradually probably has a different explanation and is better managed through a general neurology service. 

Why are TIAs a medical emergency?

Many patients who have had a TIA go on to have a stroke if the cause of the TIA is not identified and treated promptly.  The risk of an imminent stroke can be assessed using the ABCD2 score (which is outlined on the TIA referral form).  Of the strokes that follow a TIA, half will occur in the first couple of days.  In about 80% of cases the threatened stroke can be prevented if the cause of the TIA can be investigated and treated quickly.  So please do impress upon your patient the importance of attending for assessment at 8.30am on the morning after you see them.  We don’t want to meet them for the first time when they are brought in with a stroke.

Because patients with TIAs need to be seen and investigated within a day or so if a stroke is to be prevented, in our Service we see patients with TIA, 7 days a week.  You can give your patient the completedreferral form, and ask them to attend at 8.30am the following morning.  Please do mention to them, though, that if they come later than 8.30am we cannot guarantee that they will be seen that day.

What happens after a patient arrives at the TIA triage service at UCH?

Your patient will be triaged to an appropriate management pathway by the consultant on the Hyperacute Stroke Unit that day.  In about half of cases the diagnosis is not TIA, in which case the patient can be reassured and referred into an appropriate clinic (e.g. general neurology for migraine, or cardiology for a probable cardiac arrhythmia).  If the consultant thinks that TIA is still a plausible diagnosis then they may arrange tests immediately whilst the patient is waiting, or arrange outpatient investigations followed by a review in clinic, or refer patients to a dedicated TIA Clinic at the National Hospital for Neurology and Neurosurgery in Queen Square called the ‘one stop clinic’.

What is the one stop clinic?

This is a clinic that runs every Thursday at the National Hospital for Neurology and Neurosurgery.  Patients arrive at 8.30am and, after a few blood tests, are first assessed by one of the specialist registrars.  For the rest of the day they will have a series of tests directed specifically at looking for modifiable risk factors for TIA, including a cranial MRI scan, a carotid ultrasound and an echocardiogram.  The aim is that the patient’s episode can be fully investigated an managed all in a single day, although in some of our more complex cases further outpatient investigation may be needed.

Who can I talk to if I think that my patient has had a TIA?

The specialist registrar on the Hyper-acute Stroke Unit is available to speak to referring doctors 24 hours a day, 7 days a week on 07753 739286.  You do not need to call to access the TIA triage service at UCH – just complete the referral form and send the patient up the following morning – but if you have any doubt it is far better to ring than to subject your patient to a wasted journey.