TIA information for patients 

What is TIA?

Definition: TIA is a clinical syndrome presenting as acute loss of focal cerebral or monocular function, due to inadequate cerebral or ocular blood supply, and lasting less than 24 hours. 

Sometimes when people have an attack that starts like a stroke, e.g. weakness down one side of the body, the symptoms disappear by themselves.  If there are no symptoms 24 hours after the start of the attack then it is not called a stroke, it is called a ‘transient ischaemic attack’, or TIA.  The word ‘transient’ indicates that the attack gets better.  ‘Ischaemic’ means that it results from temporary blockage of a blood vessel in the brain or eye.  The word ‘attack’ is used because these are episodes of sudden onset, just as strokes are.  Episodes that start gradually over minutes or hours are unlikely to be TIAs.

Picking 24 hours as the time window that defines an attack as a TIA rather than a stroke is arbitraty, and in fact in most TIAs the symptoms only last for half an hour or so. 

If a TIA is caused by the temporary blockage of a blood vessel in the brain, then in many cases the blockage will have been caused by a blood clot which has come from  somewhere outside the head and been carried into the brain along with the blood.  The two most common sources of blood clot are:

  1. One of the large arteries in the neck.  Furring up of the arteries in the neck (‘atheroma’) can lead to the wall of the artery cracking, and a blood clot may form on the roughened surface.  Then fragments of clot, or material from the wall of the diseased artery, may break off and enter the blood stream.  The blood may carry this solid material into the brain where it may lodge in a blood vessel there causing a blockage
  2. The heart.  Normally with each heart beat the blood is squeezed out of all of the heart chambers and very little blood is left behind.  Sometimes if the heart does not fully empty, some of the blood is left behind in the heart.  In general when blood is stationary clots form, and if this happens in the heart, then at the next beat those clots may be flushed out of the heart and enter the blood stream.  As before, these could lodge in the brain and cause a TIA or stroke.

When we are assessing a patient who has had a TIA, therefore, we focus our investigations on four main areas:

  1. the blood itself (whether it is too ‘sticky’ or inclined to form clots)
  2. the brain (whether there is any evidence of damage there)
  3. the blood vessels in the neck and
  4. the heart.

How do i diagnose a TIA?

The neurological symptoms need to fit with the territory of an artery.  Do the symptoms that the patient describes sound like a stroke?  Symptoms of weakness down one side, or a loss of language are common with TIA but isolated ‘dizziness’, or memory loss are much less common. 

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. 

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 completed referral form, and ask them to attend at 8.30am the following morning.  If they come later than 8.30am we cannot guarantee that they will be seen that day.

The TIA service at UCLH

Because time is crucial in preventing a stroke, we have tried to make access to the TIA Service as simple as possible.  Your GP or other referring doctor does not need to contact us to make the referral.  If they complete our referral form and give it to you, then you can simply bring it with you.

The entry to our TIA service is through the TIA triage service that is run in the Hyperacute Stroke Unit, on the 7th Floor of the UCH Tower.  Except in rare circumstances, all patients with a recent suspected TIA will be seen there first.  You must arrive by 8.30am – if you come later there is no guarantee that you will be seen on the same day.  The reason for running this service so early is that in some cases we will need to get various tests done during the day and we need time to arrange all of those early in the day.

You will be met at 8.30am by a nurse who specialises in TIA.  Shortly after you will see an experienced stroke/TIA consultant.  Central to the ethos of our TIA service is that you receive the very best medical opinion about the attack that you have had right at the start of the process, before anything else happens.

Before you arrive

The description of the attack is of paramount importance in making the diagnosis; often tests such as brain scans will be normal.  You can really help us here:

  1. Before you come, think carefully about what exactly happened.  The doctor that sees you is likely to ask very detailed questions about how the attack started, developed and finally recovered, and you will find it much easier to answer if you have thought about it in advance.
  2. If there is anyone that witnessed your attack it is extremely helpful if they can come with you.  There may be things that they know about your appearance or behaviour during the attack that you won’t have noticed.

What happens after I arrive at the TIA Triage Service at UCH?

After a few basic details have been collected by a nurse you will go straight in to see a consultant.  In about half of the cases that are referred to our service, the consultant will make an alternative diagnosis, i.e. tell you that you have not had a TIA.  That’s almost always a good outcome, as you can be reassured that you are no longer at risk of an imminent stroke.  In this case they may simply write back to your GP to reassure them that TIA is not the diagnosis, or sometimes they might arrange for you to be seen in a clinic outside the stroke/TIA service such as a general neurology clinic.

If the consultant still feels that TIA is a possibility then there are two main possible outcomes.  One possibility is that you will be asked to stay in the hospital during the day to have various tests done, and then to see one of the doctors later on (usually about 3pm) to discuss the results of those tests.  Alternatively you may be able to leave after seeing the consultant, with an appointment to come back to a special TIA clinic 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.  Patients arrive at 8.30am and, after a few blood tests, are first seen by one of the doctors.  They will go through the whole story with you in more detail, and will ask more general questions, for example about your medical background and what medications you take.  They will usually examine you.  Throughout the rest of the day you will have a series of tests aimed specifically at investigating the possibility that you have may have had a TIA, and if so searching for the cause.

Since a TIA may be caused by a blood clot that has travelled from somewhere else in the body to lodge in an artery in the brain (see ‘What is a TIA?’ above), many of the tests are focussed on finding the possible source of such a blood clot.  One of the tests in the One Stop Clinic may be an ultrasound scan of the arteries in the neck to see if there is disease there.  In rare cases a partial blockage of the artery may be found and surgery will be recommended to clean the artery out.  Another is an echocardioagram which is an ultrasound scan of the heart to see whether there is any structural reason why blood clots might be arising from there.

At 4pm the consultant in the clinic reviews all of those tests with the experts (heart tests with a cardiologist, brain scan with a neuroradiologist, memory tests with a clinical psychologist etc.).  Once that review meeting is finished the consultant will come and see you in clinic (usually at some point between 5pm and 6pm depending on how busy the clinic has been) and make a final plan.  Often the consultant will have enough information to be confident of what is needed to prevent further TIAs or strokes and so you will be discharged.  Occasionally a few more tests will be required in which case the doctors will arrange those.

The one stop clinic is a long and tiring day, particularly for our more elderly  patients.  However the feedback that we have had shows that most patients would rather get everything done, rather than have numerous trips up to the hospital spread out over many weeks before they can be given a full explanation for their symptoms.

What happens next?

When you have reached the end of this process, the consultants will recommend the best plan (medications or, occasionally, surgery) to ensure that you have the smallest possible chance of having a TIA or stroke in the future by identifying any medical conditions that might constitute a risk of stroke and treating those before any lasting damage is done.