A cryptogenic stroke is a stroke that has no discernible cause. The patient doesn’t have a blockage in their arteries nor do they suffer from atherosclerosis or heart disease. Yet, cryptogenic strokes are surprisingly common among stroke victims. Medical researchers suspect that about 20 to 40 percent of ischemic strokes are of unknown origin. An ischemic stroke is a stroke caused by an insufficient supply of blood to the brain.
There are some intriguing studies that show that patients younger than 55 who suffer a cryptogenic stroke sometimes had an undiagnosed atrial fibrillation, which means that their heart beat irregularly. It’s believed that the atrial fibrillation caused the arteries to spasm and shut off blood to the brain. This discovery might change the way these patients are treated for their stroke, since the underlying AF would need to be addressed. Other researchers believe that a tiny embolism broke off from one area of the heart to the other and eventually made its way to the brain. The defect that allowed the embolism to do this is called a patent forman ovale, which is a hole in the wall between the atrial chambers of the upper part of the heart.
Despite the fact that the origins of a cryptogenic stroke are unknown, the results are often the same. A stroke can be mild or it can be devastating or even fatal. This depends on how much of the brain is affected and which area of the brain is affected. People may not be able to speak or see or one half of the body might be disabled. These symptoms can be permanent or they can last only a short time. Symptoms that last less than 24 hours may be the result of a transient ischemic attack or TIA.
After a stroke it is urgently important that the blood flow and thus the oxygen be restored to the brain in as little time as possible. Doctors often treat patients who have a cryptogenic stroke with Warfarin, which is an anticoagulant that’s often given to people with atrial fibrillation. Patients who are on Warfarin need to be watched closely to make sure they don’t have dangerous bleeding episodes.
Doctors might also perform an operation on the patient that makes it less likely for an embolism to travel across the heart and then migrate into the brain. This involves closing up any PFOs and other defects in the wall of the heart.