Dr Paul Cooper explains how NICE quality statements can help to improve the assessment, diagnosis, and care of people who experience a transient loss of consciousness
Read this article to learn more about:
- the importance of accurately diagnosing the underlying cause of a blackout
- the six statements that will support improvements in the accurate diagnosis of blackouts
- the initial assessment of individuals presenting with a history of blackouts.
Transient loss of consciousness (TLoC) is very common: in the UK, it affects up to 50% of the population at some point in their lives. Transient loss of consciousness is defined as the spontaneous loss of consciousness with complete recovery, without any residual neurological deficit.1 An episode of TLoC is often described as a blackout or a collapse, but some people collapse without TLoC and this article does not cover that type of situation.1
There are various causes of TLoC, including cardiovascular disorders (which are the most common), neurological conditions such as epilepsy, and psychogenic attacks (see Table 1, below).2
|Kapoor3 1990||Eagle4 1985||Day5 1982||Total (%)|
|Cardiovascular volume/tone||Vasovagal (reflex syncope)||35||64||57||156 (19)|
|Cardiac (structural heart disease/ arrhythmia)||110||15||17||142 (18)|
TLoC=transient loss of consciousness.
The diagnosis of the underlying cause of TLoC is often inaccurate, inefficient, and delayed, and as many doctors equate blackouts with epilepsy, several studies including our own have shown that between 20%–40% of patients diagnosed as suffering from epilepsy do not actually have this.6,7,8 The common term is that of 'convulsive syncope'—many people who faint exhibit jerking movements that can be notorious in being described as a 'fit'.9 Furthermore, there is huge variation in the management of TLoC. A substantial proportion of people initially diagnosed with, and treated for, epilepsy have a cardiovascular cause for their blackout. Many of these individuals will undergo expensive and inappropriate tests or inappropriate specialist referral: that is, either unnecessary referral or referral to the wrong specialty. Failing to correctly recognise a cardiological disorder means that other people with potentially dangerous conditions may not receive appropriate assessment, diagnosis, and treatment.
In Manchester, the author and his colleagues investigated 74 patients diagnosed with epilepsy, half of them continuing to have seizures despite medication.8 These investigations included detailed neurological and specific cardiological tests, and included a group of patients who also underwent long-term electrocardiogram (ECG) monitoring with an implantable loop recorder.8 An alternative diagnosis was found in more than 40% (31/74) of these patients, 13 of whom were taking antiepileptic medication. Of the 13 patients taking medication, 11 successfully stopped this when the alternative diagnosis was established.8
There are also cases where failure to identify an underlying cardiological disorder has tragic consequences.10
Therefore, the aim of the initial assessment, diagnosis, and (if needed) subsequent specialist referral of people who have had a TLoC, is to ensure that they receive the correct diagnosis quickly, efficiently, and cost effectively. This in turn leads to the development of a suitable management plan for the underlying cause of the TLoC, thus avoiding the consequences of misdiagnosis.
Principles of care
At present, there are failings in a number of key areas, including avoidable emergency hospital admissions, inappropriate specialist referral and investigations, and misdiagnosis of the cause of TLoC, leading to poor patient experience, morbidity, and indeed mortality; with appropriate attention to the healthcare pathway, many of these adverse outcomes could be preventable.
Central to establishing the correct diagnosis is a sound clinical assessment; indeed, unnecessary investigations often confuse the issue. This remains an area where an astute clinician can establish the diagnosis with his or her clinical skills. What is needed is a careful history, a physical examination (including lying and standing blood pressure), and an ECG. Important features of the history include:11
- precipitating factors and warning symptoms
- appearance and behaviour during the TLoC
- features of the recovery period.
A description from any witness to the episode is essential, where possible. Other aspects can be important: any injuries sustained and the specific situations in which the blackout occurred (e.g. exercise, posture, or if on micturition, coughing, etc).1,11
Transient loss of consciousness is a story, with a beginning, a middle, and an end. To accurately describe the process, the doctor should focus on the situation in which the TLoC occurred, any warning, what happened during the period of unconsciousness, and any symptoms that occurred during the recovery. Only when the practitioner understands what really happened can they plan appropriate investigations, and decide on a suitable management plan. I sometimes tell my trainees that they should not investigate a patient until they know what is wrong with them.
NICE quality standard for transient loss of consciousness
|1||People who have had a suspected transient loss of consciousness have an initial assessment to record details of the event, clinical history and physical examination.|
|2||People who have had a transient loss of consciousness have a 12-lead electrocardiogram (ECG) during the initial assessment.|
|3||People who have had a transient loss of consciousness and 1 or more 'red flag' signs or symptoms identified have an urgent specialist cardiovascular assessment within 24 hours of the initial assessment.|
|4||People who have had a transient loss of consciousness are not routinely offered an electroencephalogram (EEG) to investigate the event.|
|5||People who have had a transient loss of consciousness are advised not to drive while they are awaiting specialist assessment.|
|6||People with a suspected cardiac arrhythmic cause of syncope are offered an ambulatory electrocardiogram (ECG) as a first-line specialist cardiovascular investigation.|
NICE (2014). Transient loss of consciousness. Quality Standard 71.
Initial assessment: recording the event, clinical history, and physical examination—statement1
This is a crucial role for primary care, to ensure that all those individuals with a suspected TLoC have an initial assessment in which:
- the details of the event are recorded, including a witness account whenever possible
- a clinical history is taken
- a physical examination is carried out.
It is very important to collect information as soon as possible from the person and especially from any witnesses. This information gathered is critical to confirm whether or not a TLoC has actually occurred, and to establish relevant features of the event, to avoid any incorrect care.
Initial assessment: 12-lead electrocardiogram (ECG)—statement 2
All patients should have a 12-lead ECG using automated interpretation. Modern automated ECGs may be oversensitive, but they are less likely to miss significant abnormalities than a busy clinician. A number of abnormalities should be considered as 'red flags', including:
- any conduction abnormality (e.g. complete right or left bundle branch block or any degree of heart block)
- evidence of a long or short QT interval, or
- any ST segment or T wave abnormalities.
If a 12-lead ECG with automated interpretation in not available, take a manual ECG and ensure that a healthcare professional who is trained and competent in identifying the following abnormalities reviews the manual ECG:
- inappropriate persistent bradycardia
- any ventricular arrhythmia (including ventricular ectopic beats)
- long QT (corrected QT >450 ms) and short QT (corrected QT <350 ms) intervals
- Brugada syndrome
- ventricular pre-excitation (part of Wolff-Parkinson-White syndrome)
- left or right ventricular hypertrophy
- abnormal T wave inversion
- pathological Q waves
- sustained atrial arrhythmias
- paced rhythm.
This review would therefore normally, in practice, need to be carried out by a cardiology consultant or senior trainee. One concern is that even experienced cardiologists can often misinterpret the QT interval.12
Urgent specialist cardiovascular assessment within 24 hours of the initial assessment—statement 3
This is a further set of 'red flags', relating to signs and symptoms indicating that the person maybe at a high risk of a serious event and should be discussed with a cardiologist within 24 hours. The signs or symptoms include:
- any electrocardiogram (ECG) abnormality (see text above under statement 2)
- heart failure on the patient's history, or physical signs
- a blackout during exertion
- family history of sudden cardiac death in people aged younger than 40 years and/or a known inherited cardiac condition
- new or unexplained breathlessness
- a heart murmur.
If your patient has any of these features, then phone the on-call cardiology service the same day.
Initial assessment: unnecessary use of electroencephalogram (EEG)—statement 4
'Routine interictal EEG recording is one of the most abused investigations in clinical medicine and is unquestionably responsible for great human suffering. The diagnostic value of an interictal EEG is widely misunderstood. EEGs are often requested either to exclude or to prove a diagnosis of epilepsy—something that can seldom, if ever, be done.' 13
The inappropriate use of EEGs has been one of the major causes of misdiagnosis of epilepsy,14 and almost 10 years ago cost one hospital trust many millions of pounds in compensation.15,16 As someone who works in a specialist regional epilepsy service, the author does occasionally request routine EEGs, but most of the time could manage without them. Unless you are a neurologist who has a specific issue with the syndromic diagnosis of someone with established epilepsy, then just do not request any EEGs.
Driving advice—statement 5
People who have had a TLoC and are waiting to have a specialist assessment are advised not to drive in case they have a blackout while driving. These are not individuals who have had a simple uncomplicated faint, as described in the Driver and Vehicle Licensing Agency's (DVLA) guide At a glance17 (such people will have 'definite provocational factors with associated prodromal symptoms and which are unlikely to occur whilst sitting or lying'17). If the blackouts are recurrent, then the practitioner will need to check the '3 Ps':17
- provocation: the blackouts are triggered by something, such as pain
- posture: they only occur when the patient is upright
- prodrome: they are preceded by a warning.
If all three of the above are present, then the cause is likely to be reflex vasovagal syncope, which is benign in nature, and no driving restrictions for normal vehicles, heavy goods vehicles, or public service vehicles will be required. Check the DVLA guide for more details.17 No specialist assessment is needed. All other individuals need a specialist assessment before they might be allowed to drive, and must be told not to drive until they have discussed this with their specialist.
Specialist cardiovascular investigation: ambulatory electrocardiogram (ECG)—statement 6
This one is more for the specialist. To establish the true cause of a TLoC, it is necessary to record a habitual episode, not one, for example, that is triggered by artificial circumstances, such as being strapped to a tilt table, for a head-up tilt test. This means recording a spontaneous attack, and this may take days, weeks, or even months of recording. The length of recording should depend on the frequency of the attacks; a conventional 24-hour Holter monitor is almost invariably a waste of everybody’s time and the NHS’s money.
Technology is available to make recordings lasting many months; these implantable event monitors are about the size of a USB stick; they are inserted subcutaneously, and can record an ECG trace for a year or more, to be subsequently downloaded remotely. They are much more cost-effective than short-term monitoring in terms of cost-per-diagnosis, and more to the point they are far more likely to give you the answer.
Blackouts are common and often create much anxiety, both for the doctor and for the patient. They can be very satisfying to assess, as basic clinical skills, including history-taking that verges on the obsessional, can often give the diagnosis when technology has failed. It is an unfortunate observation, perhaps an indictment of modern medical education, that often a lay person can recognise a simple faint when many doctors may not.
More information on blackouts can be found on the Syncope Trust And Reflex anoxic Seizures (STARS) website (www.stars.org.uk). A more detailed discussion of the diagnosis and management of blackouts can be found in the review article co-authored by Dr Adam Fitzpatrick and Dr Paul Cooper, which was published in the journal Heart in 2006 and is freely available.
- Blackouts/TLoC are a common problem, often misdiagnosed
- A correct diagnosis can usually be established by careful clinical evaluation
- A simple bedside assessment done well, and a carefully reviewed ECG, have the highest yield in diagnosis
- Strive to speak to a witness: most people now carry mobile phones
- Never do a routine EEG
- Always do an ECG
- Unless they have had a classical simple faint, always advise your patient not to drive until they have seen the specialist
- If you do need to do any tests, plan any recording to give you a good chance of capturing a TLoC episode.
TLoC=transient loss of consciousness; ECG=electrocardiogram; EEG=electroencephalogram
- Number of adults who have experienced a transient loss of consciousness ('blackout') and who have a copy of an ECG in their notes, with either a computer report or evidence that the trace has been reviewed by a cardiologist
- Number of adults who have experienced a transient loss of consciousness ('blackout'), and in whom any ECG abnormality was detected (including QT interval outside of the normal range), who have a record that this abnormality has been addressed
- Length of wait before patients who have experienced a blackout, and who need specialist assessment, are seen in an appropriate specialist service.
GP commissioning messages
written by Dr David Jenner, NHS Alliance GMS contract/PBC Lead
- Clinical commissioning groups:
- should consider this quality standard alongside their commissioned services to ensure that the standard is met
- may wish to ensure that remote expert monitoring of ECGs is commissioned to support front-line staff in the interpretation of ECGs
- should describe referral routes in a local care pathway and consider building this into contracts with ambulance trusts, urgent care services and emergency departments
- Simple care pathways on prompt cards for first-attending clinicians may help ambulance staff and GPs who often attend to these patients and ensure that they take a good history, perform the right tests, and give appropriate advice
- It is important to ensure that rapid response clinics are available for the speedy assessment of individuals with TLoC who also have 'red flags'; this will ensure that potentially life-threatening disorders are not overlooked, and individuals are not prevented from driving for longer than necessary.
ECG= electrocardiogram; TLoC=transient loss of consciousness
- NICE. Transient loss of consciousness ('blackouts') management in adults and young people. Clinical Guideline 109. NICE 2014. Available at: www.nice.org.uk/guidance/CG109↩
- Fitzpatrick A, Cooper P. Diagnosis and management of patients with blackouts. Heart 2006; 92 (4): 559–568. ↩
- Kapoor W. Evaluation and outcome of patients with syncope. Medicine 1990; 69 (3): 160–175. ↩
- Eagle K, Black H, Cook E et al. Evaluation of prognostic classification for patients with syncope. Am J Med 1985; 79 (4): 455–460. ↩
- Day S, Cook E, Funkenstein H et al. Evaluation and outcome of emergency room patients with transient loss of consciousness. Am J Med 1982; 73 (1): 15–23. ↩
- Smith D, Defalla B, Chadwick D. The misdiagnosis of epilepsy and the management of refractory epilepsy in a specialist clinic.Q JM 1999; 92 (1): 15–23. ↩
- Scheepers B, Clough P, Pickles C. The misdiagnosis of epilepsy: findings of a population study. Seizure 1998; 7 (5): 403–406. ↩
- Zaidi A, Clough P, Cooper P et al. Misdiagnosis of epilepsy: many seizure-like attacks have a cardiovascular cause. J Am Coll Cardiol 2000; 36 (1): 181–184. ↩
- Lempert T, Bauer M, Schmidt D. Syncope: a videometric analysis of 56 episodes of transient cerebral hypoxia. Ann Neurol 1994; 36 (2): 233–237. ↩
- Chadwick D, Jelen P, Almond S. A difficult case: Life and death diagnosis.Pract Neurol 2010; 10 (3): 155–159. ↩
- NICE website. Transient loss of consciousness. Quality Standard 71. www.nice.org.uk/guidance/qs71 (accessed 2 January 2015). ↩
- Viskin S, Rosovski U, Sands A et al. Inaccurate electrocardiographic interpretation of long QT: The majority of physicians cannot recognize a long QT when they see one. Heart Rhythm 2005; 2 (6): 569–574. ↩
- Chadwick D. Diagnosis of epilepsy. Lancet 1990; 336 (8710): 291–295. ↩
- Ferrie C. Preventing misdiagnosis of epilepsy.Arch Dis Child 2006; 91 (3): 206–209. ↩
- Dyer C. £10m settlement for children misdiagnosed with epilepsy. BMJ 2005; 330: 1466. ↩
- White C. Rate of misdiagnosis of childhood epilepsy 'may not be unusual'. BMJ 2003; 326: 355 ↩
- Driver & Vehicle Licensing Agency. At a glance guide to the current medical standards of fitness to drive. Swansea: DVLA. November 2014. Available at: www.gov.uk/government/uploads/system/uploads/attachment_data/file/383428/aagv1.pdf ↩