National Clinical Guideline Centre for Acute and Chronic Conditions, Royal College of Physicians, London
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Address for correspondence Dr Norma O'Flynn, National Clinical Guideline Centre for Acute and Chronic Conditions, Royal College of Physicians, 11 St Andrews Place, Regents Park, London NW1 4LE. E-mail: ku.ca.nodnolpcr@nnylfo.amron
Received 2010 Sep 3; Accepted 2010 Sep 7.
Copyright © British Journal of General Practice, 2011
INTRODUCTION
Transient loss of consciousness [TLoC] is loss of consciousness with complete recovery. It is commonly described by the patient as a blackout. TLoC is very common and people who experience it may present to GPs during surgery hours or out of hours, or they may be referred from the ambulance services or the emergency department. There are a number of potential causes of TLoC:
uncomplicated faint or situational syncope;
orthostatic hypotension;
dysfunction of the nervous system [epilepsy];
dysfunction of the cardiovascular system [syncope]; or
dysfunction of the psyche [psychogenic attacks].
The diagnosis of the underlying cause is often inaccurate, inefficient, and delayed, and misdiagnosis is common. NICE guideline CG1091 aims to define the appropriate pathways for the assessment of patients who experience TLoC, in order to obtain the correct underlying diagnosis quickly, efficiently, and cost-effectively, and to tailor a management plan to suit their true diagnosis. The guideline includes advice on the management of uncomplicated faint/situational syncope and orthostatic hypotension, as well as on detailed testing and assessment of those people considered to have a cardiovascular cause for their TLoC.
GUIDANCE
Initial assessment
The guidance most relevant to GPs is likely to concern those areas related to initial assessment in order to determine whether the person has had TLoC, the possible causes of it, and the appropriate next steps.
History
Ask the person who has had the suspected TLoC, as well as any witnesses, to describe what happened before, during, and after the event. Try to contact, by telephone, any witnesses who are not present at the consultation. Record details about:
circumstances of the event;
person's posture immediately before TLoC;
presence or absence of any prodromal symptoms [such as sweating or feeling warm/hot] and movement during event [for example, jerking of the limbs and duration];
appearance [for example, whether eyes were open or shut] and colour of the person during the event;
any biting of the tongue [record whether the side or the tip of the tongue was bitten];
injury occurring during the event [record site and severity];
duration of the event [onset to regaining consciousness];
presence or absence during the recovery period of confusion or weakness down one side; and
current medication that may have contributed to TLoC [for example, diuretics].
Ask also about details of any previous TLoC, including number of episodes and frequency, as well as the person's medical history and any family history of cardiac disease [for example, personal history of heart disease and family history of sudden cardiac death].
Examination
Perform examination as clinically indicated. For example:
check and record vital signs [such as pulse rate, respiratory rate, and temperature] and lying and standing blood pressure, if clinically appropriate;
examine for other cardiovascular and neurological signs, such as cardiac murmurs or neurological deficit, where relevant.
Electrocardiogram
It is recommended that everyone has a 12-lead electrocardiogram [ECG] recorded using automated interpretation. If any of the following abnormalities are present, referral within 24 hours for specialist cardiovascular assessment is recommended:
conduction abnormality [for example, complete right- or left-bundle branch block or any degree of heart block];
evidence of delayed atrioventricular conduction, including bundle branch block;
evidence of a long or short QT interval; or
any ST segment or T wave abnormalities.
If an automated ECG is not available, an ECG needs to be taken and interpreted by a trained and competent health professional who can identify the ‘red flags’ listed in Box 1.
Box 1 Electrocardiogram ‘red flags’ that should prompt specialist cardiovascular assessment within 24 hours
Inappropriate persistent bradycardia
Any ventricular arrhythmia [including ventricular ectopic beats]
Long QT [corrected QT >450 ms] and short QT [corrected QT