Neurally mediated faints, also known as neurocardiogenic syncope or vasovagal syncope, refer to a temporary loss of consciousness that is caused by a sudden drop in blood pressure, resulting in a decrease in blood flow to the brain. These fainting episodes are typically triggered by certain factors that stimulate the vagus nerve, a cranial nerve that helps regulate heart rate and blood pressure.
During a neurally mediated faint, the vagus nerve becomes overly stimulated, leading to a sudden slowing of the heart rate and dilation of blood vessels. This causes blood to pool in the lower parts of the body, resulting in a decrease in blood flow to the brain. This insufficient blood supply to the brain subsequently leads to a loss of consciousness.
Factors that can trigger neurally mediated faints include pain, emotional stress, fear, prolonged standing, dehydration, intense heat, sudden changes in posture, and the sight of blood or needles. Symptoms that often precede a fainting episode may include lightheadedness, dizziness, blurred vision, nausea, and cold sweats.
While neurally mediated faints are generally harmless, they can be disruptive and may cause injury if the individual falls during an episode. Treatment for these fainting episodes includes identifying and avoiding triggers, staying properly hydrated, maintaining good blood circulation, and learning techniques to counteract the onset of fainting, such as lying down or tensing the leg muscles when warning signs occur.
