Differential diagnosis of syncope and collapse

1. Big picture

Syncope is transient loss of consciousness caused by temporary global cerebral hypoperfusion. It has a rapid onset, short duration, spontaneous complete recovery, and usually no prolonged confusion afterward.

For the final exam, approach syncope like this:

Was it true syncope?
→ Is the patient unstable?
→ Cardiac red flags?
→ Orthostatic/reflex pattern?
→ Seizure/metabolic/neurological mimic?
→ ECG + orthostatic BP + targeted tests
→ Treat the cause and prevent injury/sudden death

The examiner mainly wants you to identify dangerous cardiac syncope, because it may be the only warning before sudden cardiac death.