Syncope

1. Overview

Syncope is a transient loss of consciousness due to temporary global cerebral hypoperfusion, followed by spontaneous recovery. Patients may describe it as fainting, blackout, collapse or passing out. The OSCE priority is to distinguish true syncope from seizure, mechanical fall, hypoglycaemia, intoxication and psychogenic episodes.

Most benign episodes are vasovagal or orthostatic, but cardiac syncope must not be missed because it can be associated with serious arrhythmia, structural heart disease and sudden cardiac death. Red flags include syncope during exertion, syncope while supine, chest pain, palpitations, breathlessness, abnormal ECG, known structural heart disease and family history of sudden cardiac death.

Major categories of syncope

• Reflex syncope: vasovagal, situational or carotid sinus syncope.
• Orthostatic hypotension.
• Cardiac arrhythmia.
• Structural cardiac disease.
• Pulmonary embolism or other obstructive causes.
• Neurological mimics such as seizure.
• Metabolic mimics such as hypoglycaemia.

Important serious causes to consider

• Ventricular tachycardia or other serious arrhythmia.
• Aortic stenosis.
• Hypertrophic cardiomyopathy.
• Acute coronary syndrome.
• Pulmonary embolism.
• Aortic dissection.
• Long QT syndrome, Brugada syndrome or other inherited arrhythmia syndrome.
• Severe hypovolaemia or bleeding.
• Hypoglycaemia.
• Seizure as a mimic of syncope.

2. History Taking

Opening

• Wash hands.
• Introduce yourself.
• Confirm patient identity.
• Explain that you would like to ask about the blackout or fainting episode.
• Gain consent.
• Check whether the patient is currently well, confused, injured or symptomatic.
• If the patient is acutely unwell, state that you would assess using ABCDE and call for senior help.

Clarify the event

• Ask the patient to describe exactly what happened.
• Clarify whether there was complete loss of consciousness.
• Ask how long the episode lasted.
• Ask whether recovery was rapid or prolonged.
• Ask whether there was confusion after the event.
• Ask whether there was injury, head trauma or tongue biting.
• Ask whether the event was witnessed.
• Ask for a collateral history from a witness if available.

Circumstances before the event

• Ask what the patient was doing immediately before the episode.
• Ask whether it occurred while standing, sitting, lying down or during exertion.
• Ask whether it occurred after standing up.
• Ask whether it occurred during exercise or immediately after exercise.
• Ask whether it occurred while supine, which is concerning for cardiac syncope.
• Ask about prolonged standing, heat, dehydration, pain, fear or emotional distress.
• Ask about triggers such as coughing, urination, defecation, swallowing or turning the head.
• Ask about alcohol intake, poor oral intake, vomiting, diarrhoea or dehydration.

Prodromal symptoms

• Light-headedness.
• Dizziness.
• Nausea.
• Sweating.
• Feeling warm.
• Blurred vision or tunnel vision.
• Ringing in the ears.
• Pallor.
• Weakness.
• Palpitations.
• Chest pain.
• Shortness of breath.
• No warning symptoms, which is more concerning for cardiac syncope.

Symptoms during the event

• Loss of postural tone.
• Duration of unconsciousness.
• Abnormal movements or jerking.
• Eye rolling.
• Tongue biting, especially lateral tongue biting.
• Urinary or faecal incontinence.
• Colour change: pallor, cyanosis or flushing.
• Pulse or breathing abnormalities noted by a witness.
• Injury during the episode.

Recovery after the event

• Ask whether the patient recovered quickly or slowly.
• Ask about confusion after the episode.
• Ask about drowsiness or post-ictal state.
• Ask about headache, muscle aches or weakness.
• Ask whether they returned to baseline quickly.
• Rapid full recovery supports syncope.
• Prolonged confusion suggests seizure or another neurological cause.

Cardiac symptoms

• Chest pain or pressure.
• Palpitations before the collapse.
• Shortness of breath.
• Syncope during exertion.
• Syncope while lying down.
• Reduced exercise tolerance.
• Orthopnoea.
• Paroxysmal nocturnal dyspnoea.
• Peripheral oedema.

Neurological symptoms

• Seizure-like activity.
• Prolonged confusion.
• Focal weakness.
• Facial droop.
• Speech disturbance.
• Visual disturbance.
• Severe headache.
• Vertigo.
• Previous epilepsy or neurological disease.

Orthostatic symptoms

• Light-headedness on standing.
• Symptoms after getting out of bed or standing quickly.
• Recent dehydration.
• Vomiting or diarrhoea.
• Reduced oral intake.
• Diuretic use.
• Antihypertensive medication use.
• Autonomic neuropathy, especially in diabetes.

Situational syncope triggers

• Coughing.
• Micturition.
• Defecation.
• Swallowing.
• Pain.
• Needles or blood exposure.
• Emotional distress.
• Neck movement or tight collar suggesting carotid sinus sensitivity.

Past medical history

• Previous syncope or blackouts.
• Known arrhythmia.
• Atrial fibrillation.
• Ischaemic heart disease or previous MI.
• Heart failure.
• Valvular heart disease.
• Cardiomyopathy.
• Congenital heart disease.
• Pacemaker or ICD.
• Epilepsy or previous seizures.
• Diabetes mellitus.
• Stroke or TIA.
• Anaemia or bleeding disorder.
• Recent infection.

Drug history and allergies

• Current regular medications.
• Antihypertensives.
• Diuretics.
• Beta-blockers.
• Rate-limiting calcium channel blockers.
• Nitrates.
• Anti-arrhythmic drugs.
• Anticoagulants.
• Insulin or sulfonylureas, which may cause hypoglycaemia.
• Antidepressants or antipsychotics that may prolong QT interval.
• Recreational drugs or alcohol.
• Recent medication changes.
• Drug allergies and reaction.

Family history

• Sudden cardiac death, especially at a young age.
• Inherited arrhythmia syndromes.
• Long QT syndrome.
• Brugada syndrome.
• Hypertrophic cardiomyopathy.
• Dilated cardiomyopathy.
• Epilepsy.
• Premature ischaemic heart disease.

Social history

• Occupation, especially driving, operating machinery, working at heights or safety-critical work.
• Driving status and whether they drive professionally.
• Alcohol intake.
• Recreational drug use.
• Smoking history.
• Hydration and diet.
• Exercise level.
• Living situation and support.
• Impact on daily activities.
• Risk of falls at home.

Ideas, concerns and expectations

• Ask what the patient thinks caused the blackout.
• Ask what they are most worried about, such as heart disease, epilepsy or brain tumour.
• Ask what they were hoping would happen today.
• Acknowledge fear and explain that collapses are assessed carefully to rule out dangerous causes.

Red flags

• Syncope during exertion.
• Syncope while supine.
• Syncope without warning.
• Palpitations before syncope.
• Chest pain or severe breathlessness.
• Known structural heart disease.
• Abnormal ECG.
• Family history of sudden cardiac death.
• Severe anaemia or suspected bleeding.
• Focal neurological deficit.
• Persistent confusion after the episode.
• Recurrent unexplained episodes.
• Injury during the episode.

Closing the history

• Summarise the key points back to the patient.
• Ask if they would like to add anything else.
• Thank the patient.
• State that you would examine them, check observations, perform lying and standing blood pressure, check glucose and arrange an ECG.

3. Physical Examination

The examination should assess current stability, identify cardiac or neurological red flags, check for orthostatic hypotension and look for signs of structural heart disease, anaemia, dehydration, injury or neurological disease.

Before starting the examination

• Wash hands or use alcohol gel.
• Introduce yourself with name and role.
• Confirm the patient's identity.
• Explain the examination clearly.
• Gain consent.
• Ask if the patient currently feels dizzy, faint, short of breath or has chest pain.
• Position the patient safely, usually at 45 degrees or lying if symptomatic.
• Ensure adequate exposure while maintaining dignity.
• Ask for a chaperone if appropriate.

Initial assessment: is the patient unstable?

• Look from the end of the bed: is the patient alert, confused, pale, sweaty, breathless or injured?
• Assess whether the patient is speaking normally.
• Look for oxygen therapy, cardiac monitor, IV lines, pacemaker, ICD or resuscitation equipment.
• If the patient is acutely unwell, state that you would perform an ABCDE assessment and call for senior help.

ABCDE assessment if acutely unwell

• Airway: check if the patient can speak and whether the airway is patent.
• Breathing: assess respiratory rate, oxygen saturation, work of breathing and auscultate the chest.
• Circulation: assess pulse, blood pressure, capillary refill, ECG monitoring and obtain IV access.
• Disability: assess consciousness level, pupils if indicated and capillary blood glucose.
• Exposure: check temperature, inspect for injury, bleeding, dehydration, rash and signs of infection while maintaining dignity.

Vital signs

• Heart rate.
• Pulse rhythm.
• Blood pressure.
• Lying and standing blood pressure.
• Respiratory rate.
• Oxygen saturation.
• Temperature.
• Level of consciousness.
• Capillary blood glucose.
• Pain score if injury or chest pain is present.

Lying and standing blood pressure

• Measure blood pressure and pulse after the patient has been lying down.
• Repeat blood pressure and pulse after standing, if safe.
• Ask the patient to report dizziness or light-headedness.
• A significant postural drop supports orthostatic hypotension.
• Do not stand the patient if they are currently unstable, severely symptomatic or unsafe.

Hands

• Look for peripheral cyanosis.
• Check capillary refill time.
• Look for palmar pallor suggesting anaemia.
• Look for nicotine staining.
• Look for tremor, which may suggest thyrotoxicosis, anxiety or medication effect.
• Look for signs of injury from the fall.
• Assess hydration by checking skin turgor if appropriate.

Pulse

• Assess radial pulse rate.
• Assess rhythm: regular, regularly irregular or irregularly irregular.
• Assess pulse volume.
• An irregularly irregular pulse suggests atrial fibrillation.
• A very slow pulse may suggest bradyarrhythmia or heart block.
• A very fast pulse may suggest tachyarrhythmia.
• Compare peripheral pulses if vascular disease or dissection is suspected.

Blood pressure

• Measure blood pressure accurately.
• Check for hypotension.
• Check for postural hypotension.
• Severe hypertension may suggest underlying cardiovascular risk.
• Low blood pressure may suggest dehydration, bleeding, sepsis, arrhythmia or medication effect.

Face and eyes

• Look for conjunctival pallor suggesting anaemia.
• Look for central cyanosis.
• Look for facial injuries or bruising.
• Look for tongue injury, especially lateral tongue biting, which supports seizure.
• Look for signs of dehydration such as dry mucous membranes.
• Look for xanthelasma or corneal arcus suggesting cardiovascular risk.

Neck

• Assess jugular venous pressure at 45 degrees.
• Raised JVP may suggest heart failure, pulmonary hypertension, tamponade or massive PE.
• Assess carotid pulse if appropriate.
• Auscultate for carotid bruits if vascular disease is suspected.
• Do not palpate both carotids at the same time.
• Do not perform carotid sinus massage in a routine OSCE unless specifically asked and supervised.

Cardiovascular examination

• Inspect the chest for sternotomy scars, pacemaker or ICD.
• Palpate the apex beat and describe its location.
• A displaced apex beat may suggest cardiomegaly.
• Palpate for heaves and thrills.
• Auscultate the aortic, pulmonary, tricuspid and mitral areas.
• Listen for murmurs, especially ejection systolic murmur of aortic stenosis.
• Listen for added sounds such as S3.
• Assess for signs of heart failure.

Respiratory examination

• Inspect respiratory rate and work of breathing.
• Auscultate the lung bases for crackles suggesting heart failure.
• Listen for wheeze or reduced breath sounds if breathlessness is present.
• Consider PE or pneumothorax if syncope is associated with pleuritic chest pain or acute dyspnoea.

Neurological examination

• Assess consciousness level.
• Check pupils if indicated.
• Screen cranial nerves if neurological symptoms are present.
• Assess limb power and sensation if focal neurological symptoms are present.
• Assess coordination if appropriate.
• Assess gait only if safe.
• Check for post-ictal confusion or focal neurological deficit.

Injury assessment

• Inspect for head injury, bruising or lacerations.
• Assess for neck pain or possible cervical spine injury after a fall.
• Ask about pain before moving limbs.
• Look for limb deformity or tenderness.
• Consider urgent assessment if anticoagulated or head injury occurred.

Signs of dehydration or bleeding

• Dry mucous membranes.
• Reduced skin turgor.
• Tachycardia.
• Postural hypotension.
• Pallor.
• Abdominal tenderness or PR bleeding history if internal bleeding is suspected.
• Signs of heavy menstrual bleeding or gastrointestinal bleeding from history.

Specific findings to mention in syncope OSCE

• Aortic stenosis may cause an ejection systolic murmur radiating to the carotids.
• Hypertrophic cardiomyopathy may cause an ejection systolic murmur and exertional syncope.
• Arrhythmia may produce tachycardia, bradycardia or irregular pulse.
• Orthostatic hypotension may produce a postural blood pressure drop.
• Anaemia may produce pallor, tachycardia and flow murmur.
• Heart failure may show raised JVP, S3, basal crackles and peripheral oedema.
• Seizure may be suggested by lateral tongue biting, prolonged confusion or witnessed tonic-clonic activity.
• A normal examination does not exclude intermittent arrhythmia.

To complete the examination

To complete my examination, I would review observations, perform a 12-lead ECG, check capillary blood glucose, measure lying and standing blood pressure, send blood tests including full blood count and electrolytes, and consider ambulatory ECG monitoring or echocardiography depending on the suspected cause. I would escalate urgently if there are red flags such as exertional syncope, chest pain, palpitations, abnormal ECG, known structural heart disease or family history of sudden cardiac death.

4. Differential Diagnosis

Reflex syncope

• Vasovagal syncope: triggered by pain, fear, heat, prolonged standing or emotional stress.
• Situational syncope: triggered by coughing, micturition, defecation or swallowing.
• Carotid sinus syncope: triggered by neck movement, shaving or tight collar, usually in older patients.

Orthostatic hypotension

• Dehydration.
• Blood loss.
• Diuretic use.
• Antihypertensive medication.
• Autonomic neuropathy, especially in diabetes.
• Parkinson disease or autonomic failure.

Cardiac causes

• Bradyarrhythmia or heart block.
• Tachyarrhythmia such as ventricular tachycardia or SVT.
• Atrial fibrillation with rapid ventricular response.
• Aortic stenosis.
• Hypertrophic cardiomyopathy.
• Acute coronary syndrome.
• Heart failure.
• Pacemaker malfunction.
• Inherited arrhythmia syndromes such as long QT or Brugada syndrome.

Obstructive and vascular causes

• Pulmonary embolism.
• Cardiac tamponade.
• Aortic dissection.
• Severe pulmonary hypertension.

Neurological and metabolic mimics

• Epileptic seizure.
• Hypoglycaemia.
• Stroke or TIA, although isolated syncope is uncommon.
• Psychogenic non-epileptic attacks.
• Intoxication with alcohol or drugs.
• Mechanical fall without true loss of consciousness.

5. Investigations

Bedside tests

• Full observations.
• 12-lead ECG.
• Capillary blood glucose.
• Lying and standing blood pressure.
• Continuous cardiac monitoring if currently symptomatic or high risk.
• Pregnancy test in women of reproductive age when appropriate.
• Urine dip if dehydration, infection or pregnancy-related issue is suspected.

Blood tests

• Full blood count to assess anaemia, infection or bleeding.
• Urea and electrolytes to assess dehydration, renal function and electrolyte disturbance.
• Magnesium and calcium if arrhythmia is suspected.
• Troponin if chest pain, ECG changes or ACS is suspected.
• Thyroid function tests if thyrotoxicosis or arrhythmia is suspected.
• CRP if infection is suspected.
• D-dimer only if PE is possible and pre-test probability supports testing.

Cardiac investigations

• 12-lead ECG for arrhythmia, conduction disease, ischaemia, long QT, Brugada pattern or pre-excitation.
• Ambulatory ECG monitoring if intermittent arrhythmia is suspected.
• Holter monitor if symptoms occur frequently.
• Longer event monitor or implantable loop recorder if episodes are infrequent but concerning.
• Echocardiogram if structural heart disease, murmur, heart failure or abnormal ECG is present.
• Exercise testing if exertional syncope is reported and specialist assessment supports it.
• Cardiology referral if high-risk features are present.

Other investigations

• CT brain only if head injury, focal neurology or another neurological indication is present.
• EEG if seizure is suspected, usually after specialist assessment.
• CT pulmonary angiography if PE is suspected and imaging is indicated.
• Tilt-table testing may be considered in recurrent unexplained suspected reflex syncope.
• Carotid sinus massage may be considered in selected older patients under appropriate monitoring and supervision.

Important investigation points

• A normal ECG does not exclude intermittent arrhythmia.
• Try to establish whether the event was true syncope or a mimic.
• ECG is essential in the assessment of syncope.
• Brain imaging is not routine for simple syncope without neurological features or head injury.
• Collateral history from a witness can be as important as investigations.

6. Management

Management depends on the suspected cause and the patient's risk features. In an OSCE, always identify whether the patient needs urgent escalation, cardiac monitoring, admission or outpatient follow-up.

Immediate approach

1. Assess ABCDE if acutely unwell.
2. Call for senior help if unstable, injured, confused, hypotensive, hypoxic or having chest pain.
3. Place the patient in a safe position and prevent further falls.
4. Check capillary blood glucose.
5. Check full observations.
6. Perform a 12-lead ECG.
7. Obtain IV access if clinically indicated.
8. Treat immediately reversible causes such as hypoglycaemia, dehydration or arrhythmia.

If cardiac syncope is suspected

• Escalate urgently to senior or cardiology team.
• Attach cardiac monitoring.
• Perform ECG and repeat if symptoms recur.
• Correct reversible causes such as electrolyte disturbance.
• Arrange echocardiography if structural heart disease is suspected.
• Consider admission for high-risk features.
• Manage specific arrhythmia according to local emergency and cardiology protocols.

If vasovagal syncope is likely

• Explain the benign reflex mechanism.
• Identify and avoid triggers where possible.
• Advise good hydration.
• Advise the patient to sit or lie down when prodromal symptoms occur.
• Teach physical counter-pressure manoeuvres such as leg crossing and muscle tensing if appropriate.
• Safety-net for exertional syncope, chest pain, palpitations or recurrent unexplained episodes.

If orthostatic hypotension is suspected

• Review lying and standing blood pressure.
• Assess hydration status.
• Review medications such as antihypertensives, diuretics and nitrates.
• Treat dehydration or bleeding if present.
• Advise slow position changes.
• Consider compression stockings or specialist input in recurrent cases.
• Investigate autonomic dysfunction if clinically indicated.

If seizure is suspected

• Obtain collateral witness history.
• Check capillary blood glucose.
• Assess for injury and neurological deficit.
• Advise not to drive until assessed according to local regulations.
• Refer for neurological assessment where appropriate.
• Do not label as epilepsy from one uncertain event without proper assessment.

Driving and safety advice

• Advise the patient not to drive until medically assessed if the cause is unexplained or concerning.
• Follow local driving authority rules for syncope, seizure or arrhythmia.
• Advise avoiding swimming alone, climbing ladders, operating heavy machinery or working at heights until assessed.
• Discuss occupational implications if the patient has a safety-critical job.

Admission or urgent referral features

• Abnormal ECG.
• Syncope during exertion.
• Syncope while supine.
• Palpitations before syncope.
• Chest pain or severe breathlessness.
• Known structural heart disease.
• Family history of sudden cardiac death.
• Persistent hypotension.
• Severe anaemia or suspected bleeding.
• Neurological deficit or prolonged confusion.
• Significant injury.

Long-term management

• Treat the underlying cause.
• Optimize cardiovascular risk factors.
• Review medications that may contribute to hypotension or arrhythmia.
• Arrange cardiology follow-up if cardiac cause is suspected.
• Arrange neurology follow-up if seizure is suspected.
• Provide safety-net advice for recurrence, chest pain, palpitations, breathlessness, neurological symptoms or injury.
• Document driving and occupational advice.

7. Examiner Questions

1. What is syncope?
2. What are the main categories of syncope?
3. What features suggest vasovagal syncope?
4. What features suggest orthostatic hypotension?
5. What features suggest cardiac syncope?
6. What features suggest seizure rather than syncope?
7. Why is syncope during exertion concerning?
8. What investigations would you request initially?
9. Why is ECG important in syncope?
10. When would you request ambulatory ECG monitoring?
11. When would you admit a patient with syncope?
12. What advice would you give about driving?
13. What is the role of lying and standing blood pressure?
14. What would you ask a witness?

Suggested short answers

8. OSCE Pearls

• Clarify whether this was true loss of consciousness or a fall without blackout.
• Ask for a witness account whenever possible.
• Ask what the patient was doing immediately before the event.
• Syncope during exertion is a red flag.
• Syncope while supine is a red flag.
• Palpitations before syncope suggest arrhythmia.
• Rapid recovery supports syncope; prolonged confusion suggests seizure.
• Always ask about family history of sudden cardiac death.
• Always ask about driving and occupation.
• Check capillary blood glucose.
• Check lying and standing blood pressure.
• Perform a 12-lead ECG in syncope assessment.
• A normal examination does not exclude intermittent arrhythmia.
• Do not over-investigate simple vasovagal syncope without red flags, but do not miss cardiac features.
• Give clear safety-net and driving advice.

9. Example Presentation to Examiner

10. References

• NICE Clinical Knowledge Summary: Blackouts.
• ESC Guidelines for the diagnosis and management of syncope.
• ACC/AHA/HRS Guideline for the evaluation and management of patients with syncope.
• Local emergency medicine and cardiology protocols.
• Standard undergraduate clinical examination and OSCE teaching resources.