Unconsciousness can result from neurological, metabolic, physiological, or psychiatric causes. Initial assessment includes gathering collateral history and performing a physical exam. Level of consciousness is gauged using the AVPU scale and Glasgow Coma Scale. Key signs include abnormal pupil size, eye movement, neurological deficits, seizure activity, and distinct breath odors. Patterns of breathing may suggest specific causes. Rapid bedside tests like capillary glucose and ECG aid diagnosis. Pupillary and respiratory findings can indicate drug toxicity or brain injury. Most unconscious patients require hospital admission for evaluation, with follow-up planned post-discharge once the cause is determined. Advanced life support may be needed.