Temporary Unconsciousness:This occurs when there is a partial or complete cessation of consciousness, disrupting awareness of oneself and the surroundings. When such an episode is brief and resolves on its own, it is known as fainting or, more medically, syncope. Syncope is responsible for approximately one in every 30 visits to an emergency department. It happens due to a temporary reduction in blood flow, leading to oxygen shortage in the brain. This results in a "blackout" or fainting spell. A temporary decrease in blood supply to the brain can arise from heart issues or other non-cardiac factors:Non-cardiac Factors:Syncope is often caused by factors not directly related to the heart, such as:- A sudden drop in blood pressure when moving from a lying or sitting position to standing.- Dehydration, leading to reduced blood volume.- Blood pressure medications causing low blood pressure.- Diseases affecting the leg nerves in older adults, particularly in cases of diabetes or Parkinson's disease, when poor nerve tone in the legs draws blood away from the brain.- Transient ischemic attacks or "mini-strokes."- Fainting triggered by blood drawing or specific actions like urination, defecation, or coughing (vasovagal syncope), due to a reflex in the autonomic nervous system that slows the heart and dilates leg blood vessels. This is often preceded by nausea, sweating, or weakness.Cardiac Factors:Heart-related issues causing syncope include:- Irregular heart rhythms (too fast or too slow).- Valve abnormalities (such as aortic or pulmonary valve issues).- Narrowing in the arteries supplying the lungs (pulmonary artery stenosis).- Tears in the aorta (aortic dissection).- Widespread cardiac disease (cardiomyopathy).A thorough medical history can identify many causes of temporary unconsciousness. Dizziness upon standing in older individuals suggests postural hypotension. Fainting after urination, defecation, or coughing points to situational syncope. Cardiac-related fainting, like aortic stenosis or cardiomyopathy, often occurs during exercise. Localized weakness accompanying fainting might indicate a stroke.Blood pressure and pulse are assessed in different positions (lying, sitting, standing). Unequal arm blood pressures may indicate an aortic dissection. Heart examinations using a stethoscope can reveal valve issues. The nervous system is evaluated for sensation, reflexes, and motor function to detect neural or brain conditions. An EKG checks for heart rhythm abnormalities. Additional tests might include echocardiograms, rhythm monitoring (heart event recorders), and electrophysiologic studies of the heart’s electrical system.If heart issues are not suspected, a tilt-table test can identify causes of temporary unconsciousness. During this test, the patient is placed on a table with foot support, which is tilted upward while measuring blood pressure and pulse in different positions and observing symptoms.Many non-cardiac syncope causes (like postural hypotension, vasovagal reactions, and situational syncope) do not require treatment. Consciousness is usually regained by sitting or lying down. Patients are advised to avoid triggering situations, not to strain during elimination, to sit while coughing, and to lie down during blood drawing. Older adults should have their medications reviewed and be advised to change positions slowly to allow their body to adjust, as nerve response in the legs may be slower with age.
