Glossary of Stroke Terms

This glossary contains a number of terms you may hear when your doctor talks about stroke. You can read more about Stroke. You may also want to read about the following related topics, The Heart & Cardiovascular System, Heart Risks, Hypertension: High Blood Pressure, Aspirin & Heart and The Vascular System.

Acute stroke - a stage of stroke starting at the onset of symptoms and lasting for a few hours thereafter.

Agnosia - a cognitive disability characterized by ignorance of or inability to acknowledge one side of the body or one side of the visual field.

Aneurysm -a weak or thin spot on an artery wall that has stretched or ballooned out from the wall and filled with blood, or damage to an artery leading to pooling of blood between the layers of the blood vessel walls. (Read about "Aneurysms")

Anoxia - a state of almost no oxygen delivery to a cell, resulting in low energy production and possible death of the cell. See also in this glossary "Hypoxia"

Anticoagulants - a drug therapy used to prevent the formation of blood clots that can become lodged in cerebral arteries and cause strokes.

Antiplatelet agents - a type of anticoagulant drug therapy that prevents the formation of blood clots by preventing the accumulation of platelets that form the basis of blood clots; some common antiplatelets include aspirin and ticlopidine. See also in this glossary "Anticoagulants"

Antithrombotics - a type of anticoagulant drug therapy that prevents the formation of blood clots by inhibiting the coagulating actions of the blood protein thrombin; some common antithrombotics include warfarin and heparin. See also in this glossary "Anticoagulants"

Aphasia - the inability to understand or create speech, writing, or language in general due to damage to the speech centers of the brain. (Read about "Aphasia" "The Brain")

Apoplexy - a historical, but obsolete term for a cerebral stroke, most often intracerebral hemorrhage, that was applied to any condition that involved disorientation and/or paralysis.

Apoptosis - a form of cell death involving shrinking of the cell and eventual disposal of the internal elements of the cell by the body's immune system. (Read about "The Immune System") Apoptosis is an active, non-toxic form of cell suicide that does not induce an inflammatory response. It is often called programmed cell death because it is triggered by a genetic signal (Read about "Genetics"), involves specific cell mechanisms, and is irreversible once initiated.

Apraxia - a movement disorder characterized by the inability to perform skilled or purposeful voluntary movements, generally caused by damage to the areas of the brain responsible for voluntary movement. (Read about "The Brain")

Arteriography - an x-ray of an artery taken when a special dye is injected into the artery. It can be used to check the condition of the carotid artery. (Read about "X-rays" "Cardiovascular Tests")

Arteriovenous malformation (AVM) - a congenital disorder characterized by a complex tangled web of arteries and veins.

Atherosclerosis - a blood vessel disease characterized by deposits of lipid material on the inside of the walls of large to medium-sized arteries which make the artery walls thick, hard, brittle, and prone to breaking. (Read about "Arteriosclerosis & Atherosclerosis")

Atrial fibrillation - irregular beating of the left atrium, or left upper chamber, of the heart. (Read about "Arrhythmia")

Blood-brain barrier - an elaborate network of supportive brain cells, called glia, that surrounds blood vessels and protects neurons from the toxic effects of direct exposure to blood. (Read about "The Brain")

Carotid artery - an artery, located on either side of the neck, that supplies the brain with blood. (Read about "The Brain" "The Vascular System")

Carotid endarterectomy - surgery used to remove fatty deposits from the carotid arteries.

Central stroke pain (central pain syndrome) - pain caused by damage to an area in the thalamus. The pain is a mixture of sensations, including heat and cold, burning, tingling, numbness, and sharp stabbing and underlying aching pain.

Cerebral blood flow (CBF) - the flow of blood through the arteries that lead to the brain, called the cerebrovascular system. "The Brain"

Cerebrospinal fluid (CSF) - clear fluid that bathes the brain and spinal cord. (Read about "The Brain")

Cerebrovascular disease - a reduction in the supply of blood to the brain either by narrowing of the arteries through the buildup of plaque on the inside walls of the arteries, called stenosis, or through blockage of an artery due to a blood clot.

Cholesterol - a waxy substance, produced naturally by the liver and also found in foods, that circulates in the blood and helps maintain tissues and cell membranes. Excess cholesterol in the body can contribute to atherosclerosis and high blood pressure. (Read about "Cholesterol" "Arteriosclerosis & Atherosclerosis")

"Clipping" - surgical procedure for treatment of brain aneurysms, involving clamping an aneurysm from a blood vessel, surgically removing this ballooned part of the blood vessel, and closing the opening in the artery wall. (Read about "Aneurysms")

Computed tomography (CT) scan - a series of cross-sectional x-rays of the brain and head; also called computerized axial tomography or CAT scan. (Read about other "Cardiovascular Tests" "CT Scan - Computerized Tomography")

Coumadin^® - a commonly used anticoagulant, also known as warfarin.

Cytokines - small, hormone-like proteins released by leukocytes, endothelial cells, and other cells to promote an inflammatory immune response to an injury. (Read about "The Immune System")

Cytotoxic edema - a state of cell compromise involving influx of fluids and toxic chemicals into a cell causing subsequent swelling of the cell.

Detachable coil - a platinum coil that is inserted into an artery in the thigh and strung through the arteries to the site of an aneurysm. (Read about "Aneurysms") The coil is released into the aneurysm creating an immune response (Read about "The Immune System") from the body. The body produces a blood clot inside the aneurysm, strengthening the artery walls and reducing the risk of rupture.

Duplex Doppler ultrasound - a diagnostic imaging technique in which an image of an artery can be formed by bouncing sound waves off the moving blood in the artery and measuring the frequency changes of the echoes. (Read about "Ultrasound Imaging" "Cardiovascular Tests")

Dysarthria - a language disorder characterized by difficulty with speaking or forming words.

Dysphagia - trouble eating and swallowing.

Edema - the swelling of a cell that results from the influx of large amounts of water or fluid into the cell.

Embolic stroke - a stroke caused by an embolus.

Embolus - a free-roaming clot that usually forms in the heart.

Endothelial wall - a flat layer of cells that make up the innermost lining of a blood vessel.

Excitatory amino acids - a subset of neurotransmitters; proteins released by one neuron into the space between two neurons to promote an excitatory state in the other neuron.

Extracranial/intracranial (EC/IC) bypass - a type of surgery that restores blood flow to a blood-deprived area of brain tissue by rerouting a healthy artery in the scalp to the area of brain tissue affected by a blocked artery.

Functional magnetic resonance imaging (fMRI) - a type of imaging that measures increases in blood flow within the brain. (Read about "MRI - Magnetic Resonance Imaging")

Glia - also called neuroglia; supportive cells of the nervous system that make up the blood-brain barrier, provide nutrients and oxygen to the vital neurons, and protect the neurons from infection, toxicity, and trauma. Some examples of glia are oligodendroglia, astrocytes, and microglia. (Read about "Nervous System")

Glutamate - also known as glutamic acid, an amino acid that acts as an excitatory neurotransmitter in the brain. (Read about "The Brain")

Hemiparesis - weakness on one side of the body.

Hemiplegia - paralysis on one side of the body.

Hemorrhagic stroke - sudden bleeding into or around the brain. (Read about "Stroke")

Heparin - a type of anticoagulant.

High-density lipoprotein (HDL) - also known as the good cholesterol; a compound consisting of a lipid and a protein that carries a small percentage of the total cholesterol in the blood and deposits it in the liver. (Read about "Cholesterol")

Homeostasis - a state of equilibrium or balance among various fluids and chemicals in a cell, in tissues, or in the body as a whole.

Hypertension (high blood pressure) - characterized by persistently high arterial blood pressure defined as a measurement of systolic pressure being greater than or equal to 130 mm/Hg or diastolic pressure greater than or equal to 80 mm/Hg. Your blood pressure is considered elevated if it is greater than or equal to 120 mm/Hg systolic pressure and the diastolic number is less than 80. (Read about "Hypertension: High Blood Pressure")

Hypoxia - a state of decreased oxygen delivery to a cell so that the oxygen falls below normal levels. See also in this glossary "Anoxia"

Incidence - the extent or frequency of an occurrence; the number of specific new events in a given period of time.

Infarct - an area of tissue that is dead or dying because of a loss of blood supply.

Infarction - a sudden loss of blood supply to tissue, causing the formation of an infarct.

Interleukins - a group of cytokine-related proteins secreted by leukocytes and involved in the inflammatory immune response (Read about "The Immune System") of the ischemic cascade.

Intracerebral hemorrhage - occurs when a vessel within the brain leaks blood into the brain. (Read about "Stroke")

Ischemia - a loss of blood flow to tissue, caused by an obstruction of the blood vessel, usually in the form of plaque stenosis or a blood clot.

Ischemic cascade - a series of events lasting for several hours to several days following initial ischemia that results in extensive cell death and tissue damage beyond the area of tissue originally affected by the initial lack of blood flow.

Ischemic penumbra - areas of damaged, but still living, brain cells arranged in a patchwork pattern around areas of dead brain cells.

Ischemic stroke - ischemia in the tissues of the brain. (Read about "Stroke")

Lacunar infarction - occlusion of a small artery in the brain resulting in a small area of dead brain tissue, called a lacunar infarct; often caused by stenosis of the small arteries, called small vessel disease.

Large vessel disease - stenosis in large arteries of the cerebrovascular system.

Leukocytes - blood proteins involved in the inflammatory immune response (Read about "The Immune System") of the ischemic cascade.

Lipoprotein - small globules of cholesterol covered by a layer of protein; produced by the liver.

Low-density lipoprotein (LDL) - also known as the bad cholesterol; a compound consisting of a lipid and a protein that carries the majority of the total cholesterol in the blood and deposits the excess along the inside of arterial walls. (Read about "Cholesterol")

Magnetic resonance angiography (MRA) - an imaging technique involving injection of a contrast dye into a blood vessel and using magnetic resonance techniques to create an image of the flowing blood through the vessel; often used to detect stenosis of the brain arteries inside the skull. (Read about "MRI - Magnetic Resonance Imaging")

Magnetic resonance imaging (MRI) scan - a type of imaging involving the use of magnetic fields to detect subtle changes in the water content of tissues. (Read about "MRI - Magnetic Resonance Imaging")

Mitochondria - the energy producing organelles of the cell.

Mitral annular calcification - a disease of the mitral valve of the heart. (Read about "The Heart and Its Valves")

Mitral valve stenosis - a disease of the mitral heart valve involving the buildup of plaque-like material on and around the valve. (Read about "The Heart and Its Valves")

Necrosis - a form of cell death resulting from anoxia, trauma, or any other form of irreversible damage to the cell; involves the release of toxic cellular material into the intercellular space, poisoning surrounding cells.

Neuron - the main functional cell of the brain and nervous system, consisting of a cell body, an axon, and dendrites. (Read about "The Brain" "Nervous System")

Neuroprotective agents - medications that protect the brain from secondary injury caused by stroke. (Read about "Stroke")

Oxygen-free radicals - toxic chemicals released during the process of cellular respiration and released in excessive amounts during necrosis of a cell; involved in secondary cell death associated with the ischemic cascade.

Plaque - fatty cholesterol deposits found along the inside of artery walls that lead to atherosclerosis and stenosis of the arteries. (Read about "Arteriosclerosis & Atherosclerosis")

Plasticity - the ability to be formed or molded; in reference to the brain, the ability to adapt to deficits and injury. (Read about "The Brain")

Platelets - structures found in blood that are known primarily for their role in blood coagulation.

Prevalence - the number of cases of a disease in a population at any given point in time.

Recombinant tissue plasminogen activator (rtPA) - a genetically engineered form of tPA, a thrombolytic, anti-clotting substance made naturally by the body.

Small vessel disease - a cerebrovascular disease defined by stenosis in small arteries of the brain.

Stenosis - narrowing of an artery due to the buildup of plaque on the inside wall of the artery.

Stroke belt - an area of the southeastern United States with the highest stroke mortality rate in the country.

Stroke buckle - three southeastern states, North Carolina, South Carolina, and Georgia, that have an extremely high stroke mortality rate.

Subarachnoid hemorrhage - bleeding within the meninges, or outer membranes, of the brain into the clear fluid that surrounds the brain. (Read about "The Brain")

Thrombolytics - drugs used to treat an ongoing, acute ischemic stroke by dissolving the blood clot causing the stroke and thereby restoring blood flow through the artery.

Thrombosis - the formation of a blood clot in one of the cerebral arteries of the head or neck that stays attached to the artery wall until it grows large enough to block blood flow.

Thrombotic stroke - a stroke caused by thrombosis.

Tissue necrosis factors - chemicals released by leukocytes and other cells that cause secondary cell death during the inflammatory immune response (Read about "The Immune System") associated with the ischemic cascade.

Total serum cholesterol - a combined measurement of a person's high-density lipoprotein (HDL) and low-density lipoprotein (LDL). (Read about "Cholesterol")

tPA (tissue plasminogen activator) - a clot-busting drug. It is used to break up clots in people who are having an ischemic stroke or heart attack.

Transcranial magnetic stimulation (TMS) - a small magnetic current delivered to an area of the brain to promote plasticity and healing.

Transient ischemic attack (TIA) - a short-lived stroke that lasts from a few minutes up to 24 hours; often called a mini-stroke.

Vasodilators - medications that increase blood flow to the brain by expanding or dilating blood vessels.

Vasospasm - a dangerous side effect of subarachnoid hemorrhage in which the blood vessels in the subarachnoid space constrict erratically, cutting off blood flow.

Vertebral artery - an artery on either side of the neck. See also in this glossary "carotid artery" (Read about "Vascular System: Arteries and Veins")

Warfarin - a commonly used anticoagulant, also known as Coumadin^®.

Source: National Institute of Neurological Disorders and Stroke