Presyncope is the sensation of feeling faint or lightheaded without actually losing consciousness. Often called “near syncope,” it signals that the brain is temporarily not receiving adequate blood flow. This temporary reduction in cerebral blood flow can last from a few seconds to several minutes.
Recognizing Presyncope
During a presyncopal episode, individuals often experience noticeable symptoms. Lightheadedness and dizziness are common, sometimes accompanied by a feeling that the room is spinning. Visual disturbances may also occur, such as blurred vision or seeing black spots. Nausea, increased sweating, and a general sense of weakness are frequently reported. Other signs include ringing in the ears, a feeling of warmth or cold, heart palpitations, and abdominal discomfort. These symptoms typically precede a loss of consciousness but resolve before fainting occurs.
Common Causes of Presyncope
Presyncope occurs due to a temporary decrease in blood flow to the brain. One common cause is orthostatic hypotension, a sudden drop in blood pressure when a person stands up quickly. This happens because blood vessels do not adequately constrict, leading to reduced blood return to the heart and brain.
Vasovagal syncope, also known as the common faint, is another frequent cause. It involves an overreaction of the body’s vagus nerve.
Triggers like intense pain, emotional stress, fear, or prolonged standing can lead to a temporary drop in heart rate and widening of blood vessels, resulting in decreased blood pressure and reduced cerebral blood flow. This type can also be situational, occurring with specific actions such as urinating or eating.
Cardiac issues can also contribute to presyncope. Abnormal heart rhythms, or arrhythmias, can impair the heart’s ability to pump sufficient blood. Structural heart problems, such as aortic stenosis or hypertrophic cardiomyopathy, can also restrict blood flow from the heart.
Dehydration and low blood sugar (hypoglycemia) are other explanations for presyncope. Dehydration reduces overall blood volume, making it harder for the heart to maintain adequate blood pressure to the brain. Hypoglycemia deprives the brain of its primary energy source, glucose, which can lead to lightheadedness and weakness. Certain medications, particularly those that lower blood pressure, can also cause presyncope.
When to Seek Medical Attention
Seeking medical attention is advisable after a presyncope episode to determine the underlying cause. A medical evaluation is important if it is a first-time episode or if episodes occur repeatedly. Consult a healthcare provider if presyncope is accompanied by concerning symptoms, such as chest pain, heart palpitations, or shortness of breath. Seek immediate medical help if neurological symptoms like weakness, numbness, or slurred speech occur alongside the presyncope. Episodes during physical exercise or in individuals with pre-existing heart conditions also warrant prompt evaluation. These circumstances suggest a more serious underlying health issue.
Presyncope Versus Syncope
Presyncope and syncope are related but distinct medical terms describing states of altered consciousness due to reduced blood flow to the brain. Presyncope involves feeling faint or lightheaded without losing consciousness, with consciousness maintained throughout the episode. Syncope, on the other hand, is the medical term for actual fainting, which involves a temporary and complete loss of consciousness. While presyncope is often a precursor to syncope, it does not always progress to full loss of consciousness. Both conditions indicate a temporary reduction in blood flow to the brain, but syncope represents a more severe manifestation.