FAINTNESS, LIGHTHEADEDNESS AND LOSS OF CONSCIOUSNESS
Faintness and loss of consciousness represent different degrees of severity of the same physiologic process. Faintness is the feeling that one is about to pass out. It is characterized by lightheadedness, nausea, sweating and pallor. Loss of consciousness is the act of "blacking out." It may follow a period of faintness or may occur without warning. Syncope is the medical term for brief periods of loss of consciousness. Both faintness and syncope required medical evaluation.
Major Causes
Fainting -- Simple fainting spells are the most common type of syncope. A temporary fall in blood pressure and slowing of the pulse occur as a result of nervousness, fear, pain or surprise.
Heart Disorders -- Abnormal heart rhythms, heart attacks and blockage or leakage of the valves can decrease the blood flow to the brain. The faintness or syncope may occur suddenly or be brought on by exercise.
Orthostasis -- This term refers to a drop in blood pressure which occurs only when the person assumes an upright position. It is an exaggeration of the feeling we all experience if we get up too quickly. Orthostasis may result from dehydration, profuse bleeding or disorders or medications which affect the ability of the circulatory and nervous system reflexes to increase blood pressure. Diabetes, alcoholism, prolonged bedrest, neurologic diseases or blood pressure medications are often implicated.
Brain Disorders -- Faintness or syncope may be caused by strokes, narrowing of the arteries to the brain and seizures.
Miscellaneous -- coughing, urination, anemia, low blood oxygen, hypoglycemia, hyperventilation, hysterical fainting, carotid sinus syncope. The latter refers to loss of consciousness which occurs when pressure is placed on the major artery(s) in the neck.
Evaluation
The position of the person and the rate of onset of the faintness or syncope are important. A complete examination with attention to the blood pressure, pulse, heart, circulation and neurologic exams is mandatory. Orthostasis can be documented by checking the blood pressure standing up and lying down. Blood tests, X-rays and electrocardiogram are usually required. Syncope of unknown cause will require hospitalization for special heart and neurological testing. Heart monitoring, brain scans or X-rays, and brain wave tests may be performed. Despite thorough evaluation and extensive testing, many patients with syncope remain undiagnosed.
Treatment
The therapy of faintness and loss of consciousness must be individualized depending on the cause. Simple fainting spells should be treated by rest in the supine position with the legs elevated.
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