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Practice guidance in brief

How to manage transient loss of consciousness in adults and young people aged 16 and over

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NICE has issued evidence based guidance on the assessment, diagnosis and specialist referral of adults and young people who have experienced blackouts

Key words: Transient loss of consciousness, “blackout” guideline   


Transient loss of consciousness (TLoC) – or “blackouts” is a spontaneous loss of consciousness with complete recovery, which affects up to half of the UK’s population at some point in their lives. The condition affects all age groups and has various causes, including cardiovascular disorders - which are the most common, and range from cardiac arrhythmias to vasovagal syncope - neurological conditions such as epilepsy, and psychogenic attacks. Although these causes have very different underlying mechanisms, the history and presentation can be similar. Diagnosis is often inaccurate, inefficient, and delayed and may result in disastrous consequences. for example, sudden cardiac death as a result of misdiagnosis of congenital Long QT syndrome. Management plans vary considerably, with misdiagnosis for epilepsy alone estimated at an annual cost in the UK of up to £189 million (NICE, 2004).

In August this year, NICE issued a clinical guideline on the transient loss of consciousness (TLoC) in adults and young people aged 16 and older based on systematic reviews of best available evidence, as well as explicit consideration of cost effectiveness.The guideline aims to define the appropriate pathways for initial assessment, diagnosis and specialist referral of people who have experienced a TLoC. This is to ensure correct diagnosis is reached quickly, efficiently and cost effectively. The guideline, in the form of an algorithm, directs healthcare professionals and patients towards areas where NICE guidance already exists - for example guidance on epilepsy and falls - and provides new guidance in other areas, such as for people with syncope.

Initial assessment

A person presenting with a suspected TLoC may be assessed initially by a range of health professionals including their GP or practice nurse, a paramedic, or by staff in the accident and emergency department. It is essential that accurate information is recorded about the suspected TLoC from the patient and any witnesses. This may include obtaining evidence from paramedics, on-lookers or witnesses via the telephone. Nurses are ideally placed to ensure this information is obtained and recorded. They can also help to provide documented accurate detailed information on the TLoC event to help determine whether one has occurred.

Assess and record

Nurses should assess and record patient history, current medication, physical examination - including vital signs - and a lying and standing blood pressure if clinically indicated.  Record of cardiovascular or neurological signs and a 12-lead electrocardiogram (ECG) should also be carried out. Other relevant tests should be completed if there are concerns there is an underlying problem, such as haemoglobin levels if anaemia or bleeding is suspected.

It may be possible following initial assessment to diagnose an uncomplicated faint or situational syncope.

Uncomplicated faint

  • There are no features that suggest an alternative diagnosis.
  • There are features present such as prolonged standing, provoking factors like pain, and prodromal symptoms, such as sweating.

Situational syncope

  • There are no features that suggest an alternative diagnosis.
  • Syncope is provoked by straining during micturition or by coughing, or swallowing. 

Orthostatic hypotension

When repeated clinical measurements of lying and standing blood pressure - after standing for three minutes - confirm orthostatic hypotension causes should be considered, such as drug therapy, and managed appropriately. These patients can be discharged with appropriate advice and information.

Further assessment and referral to specialist services

Features suggestive of epilepsy include a bitten tongue, head turning to one side, no memory of the event and confusion following the event. Those people with suspected epilepsy should be referred for assessment by an epilepsy specialist (NICE, 2004).

Any one presenting with TLoC with any of the following should be referred within 24 hours for specialist cardiovascular assessment:   

  • an ECG abnormality;
  • heart failure;
  • TLoC during exertion;
  • family history of sudden cardiac death in people under 40 years;    
  • new or unexplained breathlessness;
  • a heart murmur.

Accurate nursing assessment can improve diagnostic accuracy and contribute towards positive patient outcomes. TLoC, whatever its cause, can have a profound impact on the person and their family or carers. Nurses play an important role in ensuring that people with TLoC receive the appropriate information and advice in a timely, appropriate and understandable format, including what to do if a further episode occurs, the potential impact TLoC may have on social and work activities and whether the person is allowed to continue to drive.


The NICE guideline offers a comprehensive algorithm from initial assessment through to diagnosis for patients with TLoC to ensure people receive the correct diagnosis quickly, efficiently and cost effectively leading to a suitable management plan. Detailed history-taking, a thorough clinical examination, recording a 12-lead ECG and the deployment of appropriate further testing will not only reduce misdiagnosis but also enhance treatment success and patient safety, and may lead to cost savings. Nurses will find the recommendations around initial assessment of this common condition, information gathering, advice and referral, of particular relevance.

The guideline is available for download at

AUTHORSMary E. Braine, RN, D Prof, is a lecturer in the School of Nursing and Midwifery, University of Salford, and Melesina Goodwin RN, MSc, is a clinical nurse specialist in epilepsy at Northampton General Hospital. Both are members of the NICE guideline development group.


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