This is common symptom in Emergency Medicine, often initially labelled as "collapse ?cause."
Definition of Syncope
- Transient self-limited loss of consciousness.
- The onset is usually rapid and the recovery is spontaneous, complete and usually (but not always) prompt
Patients who are still unconscious when they are brought into the ED have not had a syncopal episode since their recovery doesn't fit the criteria. They should be evaluated for coma.
Our role in the assessment of syncopal patients
- Full diagnostic assessment
- Risk stratification and appropriate disposition. Note that patients with syncope of a cardiac origin are at risk of sudden death and must be assessed in detail.
- Exclusion of significant injury.
- Consideration the patient's occupation and driving status to guide immediate discharge advice
Principal causes of syncope
- Structural cardiac or cardiopulmonary disease:
- includes valvular heart disease, LV outflow obstruction (aortic stenosis is particularly important), cardiac tamponade, pulmonary embolism
- Simple faint
- Situational syncope: micturition, cough, defecation, pain, swallowing
- Carotid sinus syndrome
Severe orthostatic hypotension
Assessment (and risk assessment)
- Circumstances prior to the episode (position, activity, predisposing factors or precipitating events).
- Symptoms at onset of episode (nausea, aura, visual, cardiac symptoms etc.).
- Details of the episode (you will need a witness, or collateral history from the ambulance crew): skin colour, duration of loss of consciousness, breathing pattern, movements, tongue biting etc.
- End of the episode: confusion, muscle aches, colour, injury, incontinence.
- Previous presyncopal or syncopal episodes, previous cardiac and medical history, family history (sudden cardiac death, epilepsy etc.
- Occupation and driving status.
Physical examination and investigations
- Focus particularly on the cardiovascular and neurological systems.
- Note the resting heart rate, BP, and SpO2 on air.
- Check for injury.
- Diagnostic carotid sinus massage should only be performed by an experienced operator, who is familiar with both the contraindications and interpretation of any effect.
- 12 lead ECG in all patients. Look for arrhythmias and conduction defects (i.e. AV block, BBB, prolonged QTc etc ). If patient has symptoms whilst in the department obtain a contemporaneous ECG (ideally 12 lead but rhythm strip also very useful).
- Blood tests are useful only if clinically indicated.
- You should do a blood glucose.
- Consider a pregnancy test in women of childbearing age.
Orthostatic hypotension (OH) is an unusual primary cause of syncope. It might be worth looking for in patients who have syncope immediately related to assuming an upright posture. Because the test (using standard BP equipment) has a low sensitivity in detecting OH, it is important to document whether symptoms occur in the absence of BP change.
The majority of patients with syncope will have normal findings on examination and be fully recovered when assessed. However risk stratification, particularly seeking cardiac causes, is crucial to disposition. If in doubt, please seek advice.
Patients may warrant referral to a Syncope Clinic for diagnostic work-up (EEG, CT, tilt test etc.). Even if you suspect the patient is suffering from simple faints remember there are other proven interventions for those with recurrent vasovagal syncope.
The incidence of 'simple faints' can be reduced (without referral to a clinic) by advising the patient about avoidance of precipitating situations, maintaining hydration, not getting overheated, and taking avoiding action if warning symptoms appear. Many patients do not realise that lying down can be effective if they feel dizzy.
Adjusting cardiovascular medications may be helpful, especially in elderly patients who are having giddy spells with postural change and occasional syncope. By reducing the dose of a cardioinhibitory medication, or omitting a vasodilator (depending on whether you think they have symptomatic bradycardia or resting hypotension ), symptom frequency can be reduced. Advise both the patient and GP of any adjustments. If reducing a diuretic or antianginal ensure the patient/carer understands that breathlessness or angina are indications for restarting their 'culprit' medications, and to see their GP.
If the patient is not admitted they should either be referred back to GP, or they can be referred directly to a neurology clinic. The latter option is best for patients in Group 2 below, or those with recurrent symptoms.
Fitness to drive
More information s available on our "driving" page.
For patients requesting a formal assessment specifically checking for driving ability, Mr. Sean O' Callaghan (Southern Mobility Assessments 087 9304335) is available for an initial fee of circa €100.
Conditions that can easily be mislabelled as syncope
Disorders with impairment or loss of consciousness
- Metabolic disorders (hypoglycaemia, hypoxia)
- TIAs of vertebrobasilar origin
Disorders resembling syncope without LOC
- Drop attacks (although these can be syncopal in origin. If they are recurrent consider referral to syncope clinic)
- Pseudosyncope, somatisation disorders
- TIAs of carotid origin
Points to note
- Brief symptoms / signs such as nausea, and diaphoresis are common and non-specific in syncope
- Brief myoclonic jerking is common in syncope. Syncope may also present as a true seizure, due to the cerebral hypoperfusion.
- Presyncope should be evaluated as being an identical entity to true syncope
Suggestive of epilepsy
- a bitten tongue
- head-turning to 1 side during TLoC
- no memory of abnormal behaviour that was witnessed before, during or after TLoC by someone else
- unusual posturing
- prolonged limb-jerking (note that brief seizure-like activity can occur during an uncomplicated faint and is not necessarily diagnostic of epilepsy)
- confusion after the event
- prodromal déjà vu or jamais vu.
Seizue less likley
- prodromal symptoms that on other occasions have been abolished by sitting or lying down
- sweating before the episode
- prolonged standing that appeared to precipitate TLoC
- pallor during the episode.
Syncope / neurology clinic
To refer a patient write a standard referral letter, preferably typed by the ED secretaries. Include information such as the circumstances of the episode, and ED assessment. A copy of the patient's ECG and any rhythm strips should be enclosed. If relevant request a 24 hour ECG tape prior to the appointment.