Temporary unconsciousness involves a partial or complete loss of awareness of oneself and one's surroundings. When this state is brief and recovery happens on its own, it is known as syncope or, more commonly outside medical circles, fainting. Syncope is responsible for roughly one out of every 30 emergency room visits. It occurs due to a temporary reduction in blood flow, leading to insufficient oxygen reaching the brain. This results in a "blackout" or loss of consciousness. Such temporary disruptions in brain blood supply can stem from heart-related issues or other non-cardiac conditions.Non-cardiac causes of syncope are most prevalent and include:- A drop in blood pressure when moving from a lying or sitting position to standing.- Dehydration, which reduces blood volume.- Blood pressure medications causing a decrease in blood pressure.- Nerve disorders in the legs in older adults, especially those with diabetes or Parkinson’s disease, which cause blood pooling in the legs and reduce brain supply.- Transient ischemic attacks (TIA), often referred to as "mini-strokes."- Reflex syncope, which can occur after blood draws or activities like urination, defecation, or coughing due to the vagus nerve triggering a heart rate slowdown and blood vessel dilation, often accompanied by nausea, sweating, or weakness.Cardiac causes of syncope include:- Irregular heart rhythms, either too fast or too slow.- Valve disorders such as aortic or pulmonary valve stenosis.- Arterial narrowing, particularly in the pulmonary artery.- Aortic dissection.- Severe coronary artery disease.Many causes of temporary unconsciousness can be identified through a thorough medical history. For instance, dizziness upon standing in older adults may suggest postural hypotension, while loss of consciousness after urination, defecation, or coughing points to situational syncope. Cardiac-related syncope, such as from aortic stenosis or cardiomyopathy, often occurs during physical activity. Weakness in specific body areas alongside loss of consciousness may indicate a stroke.To diagnose, blood pressure and pulse are checked in lying, sitting, and standing positions. Discrepancies in blood pressure between arms might signal aortic dissection. A stethoscope is used to detect abnormal heart valve sounds, and the nervous system is assessed for sensory, reflex, and motor functions to identify nerve or brain conditions. An EKG evaluates heart rhythm, while other tests like echocardiograms, rhythm monitors, and electrophysiological studies examine the heart’s electrical system.When heart issues are unlikely, tilt-table testing can identify other causes of syncope. This test involves positioning the patient on a tilting table with foot support, measuring blood pressure and pulse, and noting symptoms in different positions.Many non-cardiac syncope causes, like postural hypotension, vasovagal reactions, and situational syncope, require no treatment. Consciousness is regained by sitting or lying down, and individuals are advised to avoid triggering situations, refrain from straining during elimination, sit while coughing, and lie down during blood draws. Older adults should have their medications reviewed, and it's recommended they change positions slowly to allow their body to adjust, as nerve reflexes in the legs slow with age.
