Table 2

 Causes of collapse2

Differential diagnosisClinical clues
*Common causes
†Rare causes
Hypoxia, hypoglycaemiaShould be picked up in primary survey
Do not forget the glucose
Epilepsy*Previous history, postictal period
Affective (psychological)History of anxiety or panic disorder, hyperventilation
Dysfunction of brain stem—for example, vertebrobasilar transient ischaemic attack, basilar migraineCerebellar signs on neurological examination
Heart—for example, ischaemic heart diseaseRecent chest pain, history of myocardial infarction
Emboli—pulmonary embolismPleuritic chest pain, dyspnoea, calf pain, or swelling
Aortic obstruction—for example, stenosis, hypertrophic obstructive cardiomyopathy (HOCM)†Precipitated by exertion, cardiac murmur on auscultation
Rhythm disorders—for example, sick sinus syndrome, complete heart blockMay be picked up on primary survey if heart rate <50, history of ischaemic heart disease
Tachydysrhythmias—for example, SVT, VT, long QT syndromeHistory of palpitations, may be picked up on primary survey if heart rate >100, <5 s prodromal period
Vasovagal*Prodrome of nausea, dizziness, yawning, sweaty
ENT—for example, Ménière’s disease, acute labyrinthitis, benign paroxysmal positional vertigoHistory of vertigo, deafness, tinnitis. nystagmus on neurological examination
Situational—for example, fright, micturition, deglutition, defaecationMay be apparent from history
Sensitive carotid sinusPrecipitated by head movement
Ectopic pregnancy**History of abdominal pain, amenorrhoea, PV bleeding, positive pregnancy test
Low vascular tone
Subclavian steal**Precipitated by upper arm exertion
DRUGS—for example, antihypertensives, sympathetic blockers causing postural hypotension*Elderly patient on multiple drugs
Postural fall in blood pressure