Blood pressure is the force exerted by circulating blood against the walls of the body’s arteries. This pressure is generated by the heart pumping blood through the circulatory system, delivering oxygen and nutrients throughout the body. (6, 8, 13, 18) A seizure involves a sudden, brief disruption of brain activity, resulting from abnormal electrical signals among brain cells. (1, 11, 15, 17) These events can lead to changes in movement, sensation, behavior, or awareness.
The Link Between Low Blood Pressure and Seizure-Like Events
Low blood pressure, also known as hypotension, does not typically cause epileptic seizures directly. Instead, a significant drop in blood pressure can lead to a temporary reduction in blood flow to the brain, called cerebral hypoperfusion, which deprives brain cells of oxygen and nutrients. (23, 25, 27, 2, 23)
When cerebral hypoperfusion is severe enough, it can result in fainting, known as syncope. (2, 9, 35) During a syncopal episode, the brain’s electrical activity can be disrupted due to the lack of oxygen, sometimes leading to involuntary muscle jerks or stiffening. (22, 31, 32) These movements, often described as convulsive syncope or syncope-induced seizure-like activity, can closely resemble true epileptic seizures, making differentiation challenging. (20, 24, 34)
The brain has mechanisms, like cerebral autoregulation, to maintain consistent blood flow even with minor blood pressure fluctuations. However, this system can be overwhelmed by a sudden or severe drop in pressure. (23, 25, 29) The resulting lack of oxygen causes a temporary disturbance in brain activity, manifesting as physical signs during syncope.
While both syncope and seizures can cause loss of consciousness, the underlying mechanism differs: syncope is a circulatory issue affecting the brain’s supply, whereas a true seizure is an intrinsic brain electrical disorder. (19, 20) Differentiating these events is important for accurate diagnosis and treatment. For example, jerking movements in syncope are typically brief, often lasting only 10 to 15 seconds, and less rhythmic, with fewer than 10 jerks. (32, 34) In contrast, epileptic seizures often involve more prolonged, rhythmic jerking (more than 20 jerks) and may be followed by a period of confusion and fatigue known as the postictal state, which is less common after syncope. (19, 24, 32)
Recognizing Symptoms of Low Blood Pressure
When blood pressure drops significantly, the body, particularly the brain, struggles to receive adequate blood flow, leading to a range of noticeable symptoms. Common indicators include feelings of dizziness or lightheadedness. (2, 3, 10) Individuals may also experience blurred or fading vision, nausea, and fatigue or weakness. (2, 4, 5) These symptoms often precede or accompany a feeling of faintness or impending collapse. (2, 9)
Low blood pressure can also cause confusion or difficulty concentrating due to reduced brain perfusion. (3, 5, 10) The heart might compensate for the lower pressure by beating faster, leading to heart palpitations. (2, 10) Other signs can include cold limbs, shortness of breath, or even neck or shoulder pain. (2, 4) When these symptoms specifically occur upon standing up from a sitting or lying position, it may indicate orthostatic hypotension, a common form of low blood pressure. (3, 4, 9)
When to Seek Medical Advice
Any unexplained fainting spell, seizure-like activity, or persistent symptoms suggestive of low blood pressure warrant a medical evaluation to determine the underlying cause. (3, 4, 5) Providing a detailed account of all symptoms, their frequency, and any contributing factors can greatly assist in diagnosis. (9, 12)
A healthcare provider can conduct a thorough physical examination and recommend appropriate diagnostic tests to differentiate between syncope and other conditions, including true epileptic seizures. (16, 19, 20) This distinction is important because the treatments for these conditions differ significantly. (22, 33) For instance, an electroencephalogram (EEG) may be used to measure brain activity and help identify the electrical patterns characteristic of seizures. (19, 20) Immediate medical attention is necessary if symptoms are severe, such as loss of consciousness, profound confusion, a weak and rapid pulse, or shallow, rapid breathing. (7, 10, 12)