Common causes of unconsciousness
| Cause | Clinical clues |
|---|---|
| Vascular | |
| Intracerebral bleed | • History of preceding sudden onset headache |
| Subarachnoid haemorrhage | • Focal neurological signs |
| Stroke | |
| Metabolic | |
| Hypoglycaemia | • History of diabetes mellitus |
| Severe hyperglycaemia | • Always check the glucose |
| (hyperosmolar non ketotic coma) | |
| Severe hyponatraemia | |
| Poisoning | |
| Opiates | • History of illicit drug use, alcoholism or mental health problems |
| Tricyclics | • Presence of empty pill bottles |
| Benzodiazepines | • Pin-point pupils (opiates) |
| Carbon monoxide (accidental or deliberate) | • Dilated pupils (tricyclics or benzodiazepines) |
| Alcohol | |
| Head injury | • History of falls |
| • Scalp laceration, bruising or swelling | |
| • Periorbital bruising | |
| Epilepsy | • Previous history of fits |
| Status epilepticus (non-convulsive) | |
| Postictal | |
| Infection | • History of prodromal illness |
| Meningitis | • Rash |
| Encephalitis | • Pyrexia |
| Sepsis | • Signs of septic shock (peripheral vasodilatation, tachycardia, hypotension) |
| Hypothermia | • Temperature <35°C |