Flowchart for the initial evaluation of syncope

Goal

Recognition/risk stratification of causes for transient loss of consciousness (T-LOC). In particular causes of T-LOC with a high risk for acute cardiac death or causes such as a first epileptic convulsion.

Definitions

Transient loss of consciousness: An acute apparent loss of consciousness with a duration of less than 5 minutes, with loss of postural control, and a spontaneous and complete recovery of consciousness. Syncope: T-LOC caused by cerebral hypoperfusion, due to systemic hypotension.

Initial evaluation

Three questions are of interest:

Is the patient ABC ( airway, breathing, circulation) stabile at presentation? If not, see chapter XXX.
Is the patient suffering from T-LOC?
1. Was the patient unconscious?
  This becomes apparent from:
  - Amnesia during the unconsciousness
  - No response to speech or touch during the unconsciousness
  - Abnormal locomotion (falls, myoclonic jerks, lying still, incontinence)
  - Quick onset and short duration of the unconsciousness?
2. When consciousness is not regained: see chapter XXX (prolonged unconsciousness/coma)
Is there an obvious cause and/or is there a high risk for acute cardiac death?

For T-LOC the most important diagnostic tool is the anamnesis. Start the anamnesis with open questions. What happened? What did you feel? How did you do afterwards? The following elements must be addressed in any case (bold: risk of acute cardiac death, italic: first epileptic convulsion):

Circumstances prior to T-LOC

Posture: supine, sitting, standing
Activity: during exercise, after exercise, after standing up
Specific circumstances: micturition, defecation, coughing, swallowing, the sight of blood, (veni)puncture, fear
Predisposing factors: hot environment, fasting
Specific and rare triggers: a sounding alarm clock, cold water in the face, diving, light flashes

Start of T-LOC

Pallor, sweating, abdominal discomfort, vomiting
Palpitations: regular or irregular? Fast or slow? (beware: young people can indicate a sinus tachycardia as “palpitations”, although this is innocent)
Absence of: pallor, nausea, sweating during multiple episodes of T-LOC
Epileptic aura, focal attack

During T-LOC (eyewitness)

Duration of T-LOC
Eyes during unconsciousness: open (syncope, epilepsy) or closed (psychogenic)
Snoring (syncope: during unconsciousness; epilepsy: during recovery)
Cyanose
Myoclonic jerks (syncope: <10; epilepsy: >20)
Lateral tongue bite

During the end of T-LOC

Pallor, sweating, nausea, abdominal discomfort, vomiting
Incontinence of urine or defecation
Prolonged confusion (i.e. dysfunctional imprinting; sleeping is not confusion)
Myalgia

Medical background and history

History of cardiac disease
Familial acute death < 40 years old with an unknown cause
Many episodes of T-LOC/long duration of T-LOC (psychogenic)
Medication (anti diabetic drugs, antihypertensive drugs, psychiatric medication), intoxications

Useful information from anamnesis

Palpitations, fever, loss of blood, dyspnea on exertion

Physical examination: general physical examination

Points of interest

Auscultation of the heart: are indications for structural heart disease present or an arrhythmia present?
Supine and standing blood pressure and pulse. After 5 minutes of supine rest the blood pressure and pulse must be measured at least twice. The patient then rises from supine to standing position. Within 3 minutes of standing the blood pressure and pulse must be measured again. One speaks of orthostatic hypotension if the systolic blood pressure drops with at least 20 mmHg, or the diastolic blood pressure drops with at least 10 mmHg within 3 minutes. If the blood pressure dropped it is wise to continue measuring while standing to see if it will drop further. One must also ask the patient if he/she experiences symptoms during standing.
Neurological examination: in particular attention for the later tongue bite
Trauma (capitis) due to a fall during T-LOC

ECG: pay particular attention to

Bifascicular block
Intraventricular conduction delay (QRS > 0.12 sec)
Mobitz Type 1 second-degree AV block (Wenckebach)
Asymptomatic sinusbradycardia (< 50/min), Sino-arterial exit block or sinus pause > 3 sec in absence of negative chronotropic drugs
Non-sustained VT
Pre-excited QRS-complex (normal: QTc male 300-450 ms; female 300-460 ms)
Long or short QT-interval
Early repolarization
RBBB pattern with ST-elevation in V1-V3 (Brugada syndrome)
Negative T waves in right precordial leads, epsilon wave and late ventricular potentials are suggestive for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
ST-elevations and Q’s are suggestive for myocardial infarction

Laboratory only when indicated: Hb, elektrolytes (sodium, potassium, calcium, magnesium), glucose, troponine, creatine kinase, pro- BNP, d-dimer, arterial blood gas analysis

Risk stratification

If no cause is found using the information provided above, one must determine whether the risk of a cardiovascular event or death is high.

Patients with T-LOC with the following characteristics have an increased risk for a cardiovascular event or death, and must be hospitalized or extensively evaluated.

Structural heart disease and coronary artery disease
Clinical signs that are suggestive for cardiac syncope
- Syncope during exercise or while in supine position
- Specific triggers, like a sounding alarm, or diving
- Absence of prodromal symptoms (during multiple episodes of T-LOC)
- Palpitations prior to syncope
- Familial history of acute cardiac death or cardiac disease
ECG characteristics mentioned earlier

Policy

The policy is determined by the cause of the T-LOC, with the risk of acute cardiac death or the magnitude of the risk for the patients’ health.

Category RED (cardiac cause and first convulsion): Acute hospitalization and (rhythm) observation (cardiac) or imaging of the brain (convulsion)
Category ORANGE (orthostatic hypotension, very frequent reflex syncope, psychogenic pseudosyncope): policlinical evaluation preferably in a syncope unit
Category GREEN (isolated reflex syncope, recognized epilepsy): explain and potentially follow-up by GP or attending physician.

References

Task Force for the Diagnosis and Management of Syncope, European Society of Cardiology (ESC), European Heart Rhythm Association (EHRA), Heart Failure Association (HFA), Heart Rhythm Society (HRS), Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M, Dahm JB, Deharo JC, Gajek J, Gjesdal K, Krahn A, Massin M, Pepi M, Pezawas T, Ruiz Granell R, Sarasin F, Ungar A, van Dijk JG, Walma EP, and Wieling W. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J. 2009 Nov;30(21):2631-71. DOI:10.1093/eurheartj/ehp298 | PubMed ID:19713422 | HubMed [guideline]
Thijs R.D. Gebruikte termen voor “voorbijgaande bewusteloosheid” op de Eerste Hulp; een inventarisatie. Nederlands Tijdschrift voor Geneeskunde (2005) 149, 1625-1630.
[Thijs]