brain, spinal cord, and nerve disorders
Ischemic Stroke
Symptoms of Ischemic Stroke
Usually, symptoms of an ischemic stroke occur suddenly and are often most severe a few minutes after they start because most ischemic strokes begin suddenly, develop rapidly, and cause death of brain tissue within minutes to hours. Then, most strokes become stable, causing little or no further damage. Strokes that remain stable for 2 to 3 days are called completed strokes. Sudden blockage by an embolus is most likely to cause this kind of stroke. In about 10 to 15% of strokes, damage continues to occur and symptoms continue to worsen for up to 2 days, as a steadily enlarging area of brain tissue dies. Such strokes are called evolving strokes. In some people, symptoms affect one arm, then spread to other areas on the same side of the body. The progression of symptoms and damage usually occurs in steps, interrupted by somewhat stable periods. During these periods, the area temporarily stops enlarging or some improvement occurs. Such strokes are usually due to the formation of clots in a narrowed artery. Strokes caused by an embolus often occur during the day, and a headache may be the first symptom. Strokes caused by a blood clot in a narrowed artery often occur at night and are first noticed when the person wakes up. Many different symptoms can occur, depending on which artery is blocked and thus which part of the brain is deprived of blood and oxygen (see Brain Dysfunction by Location ). When the arteries that branch from the internal carotid artery (which carry blood along the front of the neck to the brain) are affected, the following are most common: Blindness in one eye Loss of vision on either the left side or the right side of both eyes Abnormal sensations, weakness, or paralysis in one arm or leg or on one side of the body When the arteries that branch from the vertebral arteries (which carry blood along the back of the neck to the brain) are affected, the following are most common: Dizziness and Vertigo None Double Vision or loss of vision in both eyes Generalized weakness on one or both sides of the body Many other symptoms, such as difficulty speaking (for example, slurred speech), impaired consciousness (such as confusion), loss of coordination, and urinary incontinence, can occur. Severe strokes may lead to Stupor and Coma . In addition, strokes, even milder ones, can cause depression or an inability to control emotions. For example, people may cry or laugh inappropriately. Some people have a Seizure Disorders when the stroke begins. Seizures may also occur months to years later. Late seizures result from scarring or materials that are deposited from blood in the damaged brain tissue. Occasionally, fever develops. It may be caused by the stroke or another disorder. If symptoms, particularly impaired consciousness, worsen during the first 2 to 3 days, the cause is often swelling due to excess fluid (edema) in the brain. In large strokes, the swelling in the brain is typically at its worst about 3 days after the stroke begins. Symptoms usually lessen within a few days, as the fluid is absorbed. Nonetheless, the swelling is particularly dangerous because the skull does not expand. The resulting increase in pressure can cause the brain to shift, further impairing brain function, even if the area directly damaged by the stroke does not enlarge. If the pressure becomes very high, the brain may be forced sideways and downward in the skull, through the rigid structures that separate the brain into compartments. The resulting disorder is called Herniation: The Brain Under Pressure , which can be fatal. Strokes can lead to other problems (complications): If swallowing is difficult, people may not eat enough and become malnourished and dehydrated. Food, saliva, or vomit may be inhaled (aspirated) into the lungs, resulting in Aspiration Pneumonia and Chemical Pneumonitis . Being in one position too long can result in Pressure Sores and lead to muscle loss, deconditioning, urinary tract infections, and permanent shortening of muscles (contractures). Not being able to move the legs can result in the formation of blood clots in deep veins of the legs and groin ( Deep Vein Thrombosis (DVT) ). Clots in the deep veins of the legs can break off, travel through the bloodstream, and block an artery to a lung (a disorder called Pulmonary Embolism (PE) ). People may have difficulty sleeping. The losses and problems resulting from the stroke may make people depressed. 