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Flowchart for the initial evaluation of syncope
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.
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.
Three questions are of interest:
- Is the patient ABC ( airway, breathing, circulation) stabile at presentation?
- Is the patient suffering from T-LOC?
- A: 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)
- B: Quick onset and short duration of the unconsciousness?
- A: Was the patient unconscious?
- 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 medical history. Start history taking with open questions.
What happened? What did you feel? How did you do afterwards?
The following elements must be addressed in any case (RED: risk of acute cardiac death, GREEN: 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, 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)
- Total number of 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)
- Rapid spontaneous and complete recovery
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, anti-hypertensive 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 lateral 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
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
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.
- 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 |
Thijs R.D. Gebruikte termen voor “voorbijgaande bewusteloosheid” op de Eerste Hulp; een inventarisatie. Nederlands Tijdschrift voor Geneeskunde (2005) 149, 1625-1630.