Syncope, the medical term for fainting, is a temporary loss of consciousness from reduced blood flow to the brain. When this happens more than once, it is called recurrent syncope. It is a symptom, not a standalone disease, and its significance is determined by its underlying cause. Fainting results in a loss of muscle control, which often causes a person to fall, allowing blood flow to return to the brain and consciousness to be regained. Understanding why these episodes happen is the first step toward management.
Underlying Causes of Repeated Fainting
Recurrent syncope falls into three main categories, the most common being neurally mediated syncope (NMS). This arises from a temporary miscommunication in the autonomic nervous system, which regulates heart rate and blood pressure. Triggers like severe pain, emotional distress, the sight of blood, or prolonged standing can cause a sudden drop in both, leading to fainting. Often called vasovagal syncope, this type accounts for many fainting episodes, particularly in younger people.
Another primary cause is orthostatic hypotension, a rapid drop in blood pressure upon standing. When a person stands up, gravity pulls blood into the legs, and for those with this condition, the body’s response to stabilize blood pressure is inadequate. It is more common in older adults and can be influenced by dehydration, certain medications, or underlying conditions like Parkinson’s disease or diabetic neuropathy.
The most serious category is cardiac syncope, where an underlying heart condition reduces blood flow to the brain. This can be due to heart rhythm disturbances (arrhythmias), where the heart beats too slowly or too quickly. Structural problems with the heart, such as narrowed valves or thickened heart muscle, can also impede blood flow. Because these conditions can be serious, identifying a cardiac cause is a priority.
The Diagnostic Journey
The diagnostic process begins with a detailed account of your fainting episodes. Your physician will ask about the circumstances, including your posture, activity, and any preceding symptoms. The initial consultation also includes a physical exam and blood pressure measurements while sitting and standing to check for orthostatic hypotension.
An electrocardiogram (ECG or EKG) is a standard test that provides a snapshot of the heart’s electrical signals and can reveal rhythm problems. Since fainting spells can be infrequent, continuous monitoring may be recommended to capture an event. A Holter monitor is a portable ECG worn for 24 to 48 hours, while an event monitor can be used for longer periods to record heart activity when symptoms occur.
A tilt-table test may be used to diagnose neurally mediated syncope. During this procedure, you lie on a table that is slowly tilted upward while your heart rate and blood pressure are monitored to see if the change provokes fainting. If a structural heart problem is suspected, an echocardiogram uses ultrasound waves to create images of your heart’s muscle and valves.
Approaches to Management and Treatment
For neurally mediated syncope or orthostatic hypotension, treatment begins with lifestyle adjustments. Increasing fluid and salt intake helps maintain blood volume, while compression stockings prevent blood from pooling in the legs. You may also be taught to recognize triggers and use counter-pressure maneuvers, like crossing legs, to raise blood pressure when symptoms appear.
For orthostatic hypotension, medication adjustments may be needed. If you take drugs that lower blood pressure, your doctor may alter the dosage or switch medications. Other drugs may be prescribed to stabilize blood pressure, like fludrocortisone, which helps retain salt and water, or midodrine, which tightens blood vessels.
When a cardiac condition is the cause, treatment focuses on the heart problem. A pacemaker may be implanted for a slow heart rate, while an implantable cardioverter-defibrillator (ICD) can correct dangerously fast rhythms with an electrical shock. In cases where a structural issue like a faulty valve is the cause, surgery may be required.
Recognizing Warning Signs and Immediate Actions
Learning to recognize the warning signals before a faint, known as the prodrome, is an important safety measure. These symptoms provide an opportunity to take action and prevent a fall-related injury. Common warning signs include:
- Feeling lightheaded or dizzy
- Vision changes like seeing spots or tunnel vision
- Muffled hearing
- A sudden onset of nausea
- Sweating
- A feeling of weakness
When these warning signs appear, the most effective action is to lie down flat and elevate your legs above your heart. This position helps restore blood flow to the brain. If lying down is not an option, sit down and lower your head between your knees.
Certain situations involving fainting warrant immediate emergency medical care. You should go to the emergency room if you faint during physical exercise, experience chest pain or heart palpitations, or lose consciousness without any warning. Fainting that results in a significant injury also requires urgent medical attention, as these signs can indicate a more serious underlying cause.