Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
A stroke is a medical event in which blood flow to the brain is disrupted. In an ischemic stroke, this disruption is caused by a blocked artery. In a hemorrhagic stroke, it’s caused by the rupture of a blood vessel that allows a mass of blood to disrupt circulation and cause pressure against the brain. But where does such an event begin and end? At what point do you consider the stroke a thing of the past? How long does a stroke last from the first symptom to its conclusion?
You might consider the stroke’s beginning as the first moment in which the brain begins to be deprived of blood. This is usually also when the signs of stroke are first observed, coincident with the first death of brain cells, which are destroyed at a rate of 2 million per minute as the stroke goes on. A stroke can be said to have ended when blood flow to the affected area of the brain is restored medically, or—if the stroke is left untreated—when the damage to the brain has stabilized.
In most cases, a stroke in which the patient receives prompt and effective medical care will end sooner than one that is allowed to run its course. It’s therefore crucial that every stroke be treated as the pressing emergency it is. The longer the brain is deprived of oxygen-rich blood, the more permanent damage will occur.
A stroke’s duration will depend in part on the type and severity of the stroke. Because of differences related to these and other factors, there is enormous variation in stroke duration. One stroke might last only for a couple of minutes, while another could continue doing damage for a number of days.
Ischemic strokes. These are the most common type, accounting for nearly 87% of all strokes. The duration of an ischemic stroke may be affected by the patient’s overall health. When the blockage occurs, the initial damage centers on the immediately obstructed part of the brain, called the core of the stroke, whose cells begin dying off. Surrounding that core is an area called the penumbra, where cells can temporarily continue getting oxygenated blood indirectly via small vessels despite the blockage of the large artery. But the window of survival of the cells in the penumbra is brief, only a few hours long. If the blockage is not removed so that blood flow to the affected area is restored, even the cells in the penumbra cannot recover.
According to one study, the average ischemic stroke duration is nearly 7 hours, but bear in mind that that figure may include patients who didn’t receive medical intervention until nearly a day after their strokes.
Hemorrhagic. The symptoms of a hemorrhagic stroke, in which blood from a ruptured vessel leaks in the brain, disrupting normal circulation, may begin almost immediately or may occur hours later. The onset of a hemorrhagic stroke is often (but certainly not always) experienced as a sudden, inexplicable headache. As the stroke unfolds, the pool of blood spreads along the brain’s tissue, putting pressure on cells which may injure or kill them. This process of expansion of the pool of blood may play out over the course of three to 12 hours. But the impact on the brain is not yet complete. In response to the damage caused by the bleeding, the brain begins swelling, which can put further pressure on cells. This swelling process can continue for 14 days. Doctors usually treat hemorrhagic stroke by giving medications to bring down blood pressure or to encourage clotting to stop the bleeding. If the stroke causes too much pressure inside the skull, physicians may operate to remove the excess blood and relieve the pressure on the brain.
Transient ischemic attack. A TIA or mini-stroke is dangerous in and of itself, and should be treated as just as serious an emergency as a full-blown stroke. But it also is frequently a harbinger of more strokes to come, with a third of TIA patients experiencing stroke afterward.
As the name implies, a mini-stroke is one of relatively short duration which does not cause permanent damage despite bringing symptoms similar to those of a full-blown ischemic stroke. A blockage appears briefly, then disappears, allowing the affected brain cells to recover from the brief spell of oxygen deprivation. A TIA is usually over in a couple of minutes, although in some cases it can last for an hour or two. Rarely, it can go on for much longer, possibly up to 24 hours. Before 2009, the American Heart Association and the American Stroke Association defined TIA as a blockage whose symptoms lasted less than 24 hours and typically less than one hour without death of brain tissue. But research using MRIs revealed that almost half of strokes classified as TIAs had indeed caused lasting damage, and the time component was dropped from the definition to emphasize the lack of long-term damage rather than a specific duration of symptoms.
