Some types of fainting (syncope) are medical emergencies. Cardiac syncope, for example, which is where fainting is caused by an underlying problem with your heart, may require urgent medical attention.
Your GP will be able to diagnose other types of fainting, such as situational syncope, which is fainting caused by a bodily function or activity, such as sneezing or laughing. What type of fainting you have will determine whether you need to have any treatment.
Emergency medical advice
Fainting can sometimes be mistaken for a serious medical condition, such as a stroke. A stroke is a medical emergency that occurs when the blood supply to the brain is interrupted.
You should dial 999 immediately to request an ambulance if you suspect that you or someone else is having a stroke.
The main symptoms of stroke can be remembered with the word FAST, which stands for Face-Arms-Speech-Time.
- Face: the face may have fallen on one side, the person may not be able to smile, or their mouth or eye may have drooped.
- Arms: the person with a suspected stroke may not be able to raise both arms and keep them there due to arm weakness or numbness.
- Speech: the person may have slurred speech.
- Time: it is time to dial 999 immediately if you see any of these signs or symptoms.
You should also dial 999 to request an ambulance if someone faints and does not regain consciousness after a minute or two.
When to see your GP
Most cases of fainting are not a cause for concern, but you should see your GP after you have fainted, particularly if you:
- have no previous history of fainting
- experience repeated episodes of fainting
- injure yourself during a faint
- have diabetes, which is a condition that is caused by too much glucose in the blood
- are pregnant
- have a history of heart disease, which is where your heart's blood supply is blocked or interrupted
- experienced chest pains, an irregular heartbeat or a pounding heartbeat before you lost consciousness
- experienced a loss of bladder or bowel control
- took longer than a few minutes to regain consciousness
Information for your GP
To help your GP to make an accurate diagnosis, you should give them as much information as possible about the circumstances surrounding your fainting episode. Possible useful information includes:
- where you were and what you were doing just before you fainted
- whether you experienced any symptoms or unusual sensations before you fainted, such as sweating
- whether there is a history of heart disease in your family
- whether you have experienced previous episodes of fainting
- whether you are taking any medication
- how long you were unconscious for
- whether you experienced any symptoms after you regained consciousness, such as weakness or confusion
STARS, a charity for people who experience fainting, have produced a blackouts checklist to give you advice if you’re preparing for an appointment with your GP. It also contains information about what to expect if you have a hospital appointment.
Assessment
During the assessment, your GP will ask about the circumstances surrounding your fainting episodes and your recent medical history. They may:
- Measure your blood pressure using a sphygmomanometer. This device has an inflatable cuff that goes around your upper arm and a scale of mercury, like a thermometer, as a pressure gauge.
- Listen to your heartbeat using a stethoscope. This instrument has a metal disc that is placed on your chest and a pair of ear pieces that your GP uses to listen to your heartbeat
Your GP will need to check that the fainting was not caused by problems with your heart. If there are any signs of a heart problem, such as an unusual heartbeat, they may suggest that you have an electrocardiogram (ECG).
Electrocardiogram (ECG)
An ECG records the rhythm and electrical activity of your heart. A number of small, sticky patches called electrodes are placed on your arms, legs and chest. Wires connect the electrodes to an ECG machine.
Every time your heart beats, it produces tiny electrical signals. The ECG machine traces these signals on paper, recording any abnormalities in your heartbeat.
An ECG is usually carried out at a hospital or GP surgery. The procedure takes about five minutes and is painless.
Carotid sinus test
Your GP may massage your carotid sinus to see whether it makes you feel faint or lightheaded. Your carotid sinus is a collection of sensors in the carotid artery, which is the main artery in your neck that supplies blood to your brain.
If the carotid sinus massage causes symptoms, it may indicate that you have carotid sinus syndrome. See Fainting - causes for more information about this condition.
Blood tests
Blood tests may be carried out to rule out conditions such as diabetes or anaemia. Anaemia is a condition where the body does not produce enough oxygen-rich red blood cells.
Tilt-table test
Your GP may suggest you have a test called the tilt-table test to rule out orthostatic hypotension as a possible cause of your fainting. If your GP does not have access to a tilt-table, you may be referred to a specialist, for example at a hospital, to have this test.
During the test, you will be strapped to a table that is tilted upwards. If the sudden move from a horizontal to a vertical position makes you feel lightheaded, it is likely that you have orthostatic hypotension.
Alternatively, your GP may measure your blood pressure while you are lying down and again after you stand up. You may have orthostatic hypotension if your blood pressure falls after you stand up.
If you have orthostatic hypotension, you may be asked further questions to help determine the cause. For example, it can sometimes occur as a side effect of some medications.
Diagnosing the cause
If tests are unable to find a serious underlying cause for your fainting, it is likely that you have experienced vasovagal syncope (see Fainting - causes). If this is the case, further testing and treatment will probably not be needed.
If tests reveal that there is an underlying cause of your fainting, such as a heart problem or orthostatic hypotension, your GP may recommend treatment (see Fainting - treatment).
