Vasculitis Terms A-Z
  • A
  • B
  • C
  • D
  • E
  • F
  • G
  • H
  • I
  • J
  • L
  • M
  • N
  • P
  • R
  • S
  • T
  • U

Alkylating agents: A group of drugs originally used to treat cancer, now used (in lower doses) to treat some forms of severe vasculitis.

Anaphylaxis: Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as the venom from a bee sting.

Anemia: Condition resulting from low red blood cell counts.

Aneurysm: Weakening of a blood vessel wall by inflammation. Sometimes leads to rupture of the vessel.

Angina: Angina is a type of chest pain caused by reduced blood flow to the heart muscle. It is typically described as squeezing, pressure, heaviness, tightness or pain in your chest. Many people with angina say it feels like someone is standing on their chest.

Antibodies: Special protein substances made by the body’s white blood cells for defense against bacteria and other foreign substances.

Antinuclear antibody (ANA): Proteins in the blood that react with the nuclei of cells. ANA is seen in 5% of healthy individuals, and in most patients with autoimmune diseases.

Anti-neutrophil cytoplasmic antibodies (ANCA): Anti-neutrophil cytoplasmic antibodies. These antibodies are found in patients with some forms of vasculitis, particularly eosinophilic granulomatosis with polyangiitis (Churg-Strauss), granulomatosis with polyangiits (Wegener’s), and microscopic polyangiitis.

Aortitis: The inflammation of the aortic wall.

Arteritis: Inflammation of the walls of an artery.

Artery: Blood vessel that transports blood from the heart to the tissues.

Arthralgia: Aches or pains in a joint.

Arthritis: Inflammation of a joint, usually accompanied by pain, swelling, and stiffness, and resulting from infection, trauma, degenerative changes, metabolic disturbances, or other causes.

Autoantibody: Antibody to one’s own tissues or cells.

Autoimmune or autoimmunity: Allergy to one’s own tissues.

Biologic agents: Targeted immune therapies.

Biopsy (skin, nose or sinus, lung, kidney): Removal of a bit of tissue for examination under the microscope.

Blood tests:

  • CBC: Complete blood count: Blood test that measures the amounts of red blood cells, white blood cells, and platelets in the body.
  • CRP: C-reactive protein: Blood text, which can be measured in your blood, increases when there's inflammation in your body.
  • Creatinine: Breakdown product of creatine, a muscle component.
  • Erythrocyte Sedimentation Rate (ESR): Test that measures the precipitation of red cells in a column of blood; high rates usually indicate increased disease activity.

Bone densitometry (Dexa scan): A bone scan is a nuclear imaging test that helps diagnose and track several types of bone disease. Your doctor may order a bone scan if you have unexplained skeletal pain, bone infection or a bone injury that can't be seen on a standard X-ray.

Bronchoscopy: A procedure to see inside your lungs.

Capillary: Small blood vessels connecting arteries and veins.

Claudication: A symptom caused by lack of blood flow to the muscles caused by narrowing of the arteries. The symptom of claudication usually occurs in the calf or in an arm, and is an aching pain that resolves with rest.

Clinical trial: A research study to answer specific questions about new therapies or new ways of using known treatments. Clinical trials are used to determine whether new drugs or treatments are both safe and effective.

Conjunctivitis: Inflammation of the most superficial layer of the eye, characterized by redness and often accompanied by a discharge. Conjunctivitis can be caused by certain infections, but is also associated with some types of vasculitis.

Cryoglobulins: Protein complexes circulating in the blood that are precipitated by cold.

Cutaneous: Relating to the skin.

Cytokine: Group of chemicals that signal cells to perform certain actions.

Cytoplasmic: The protoplasm outside the nucleus of a cell.

Dialysis: In dialysis, a machine filters wastes, salts and fluid from your blood when your kidneys are no longer healthy enough to do this work. Hemodialysis is the most common way to treat advanced, permanent kidney failure. The procedure can help you carry on an active life despite failing kidneys.

Diffuse Alveolar hemorrhage (DAH): A subset of diffuse pulmonary hemorrhage when bleeding is diffuse and directly into the alveolar spaces. It can occur in a vast number of clinical situations and at time can be life threatening.

Disease activity (or just “activity”): Disease activity represents the aspects of your disease that are caused by active inflammation in organs targeted by the vasculitis and respond to treatment with steroids and immunosuppressive drugs.

Disease damage: Represents the parts of your disease that do not respond to anti-inflammatory and immunosuppressive therapy.

Disease flare: Represents recurrence of inflammatory activity of the underlying vasculitis after a state of remission has been achieved with treatment.

Disease Remission: Remission means the absence of disease activity.

DNA: Deoxyribonucleic acid; the body’s building blocks; a molecule responsible for the production of all the body’s proteins.

Dyspnea: Shortness of breath.

Echocardiography: A painless test that uses sound waves to create a moving picture of your heart. The test gives information about the size and shape of your heart and how well your heart chambers and valves are working.

Edema: Swelling caused by retention of fluid.

EKG (Electrocardiogram): An EKG is a simple, painless test that records the heart’s electrical activity. You might have this test to show whether vasculitis is affecting your heart.

ELISA (enzyme-linked immunosorbent assay): Very sensitive blood test for detecting the presence of autoantibodies.

End-stage renal disease: ESRD is when the kidneys stop working well enough for you to live without dialysis or a transplant. This kind of kidney failure is permanent.

Eosinophils: A type of white blood cell containing cytoplasmic granules that are stained easily by eosin or other acid dyes.

Erythema: Reddish hue.

Etiology: The cause or origin of a disease.

Fatigue: Chronic fatigue is a nearly constant state of weariness that develops over time and diminishes your energy and mental capacity.

Flare ”disease flare”: A disease flare represents recurrence of inflammatory activity of the underlying vasculitis after a state of remission has been achieved with treatment.

Gene: Consisting of DNA, it is the basic unit of inherited information in our cells.

Glucocorticoids: Synthetic steroids.

Glomerulonephritis: Inflammation of the glomerulus of kidney.

Glomerulus: A tuft of capillaries within the kidney that filters blood in order to form urine. Normally, each kidney has approximately 1 million glomeruli.

Hepatitis B: A serious liver infection caused by the hepatitis B virus (HBV).

Hepatitis C: An infection caused by a virus that attacks the liver and leads to inflammation. Most people infected with the hepatitis C virus (HCV) have no symptoms.

Hemorrhage: An escape of blood from a ruptured blood vessel, especially when profuse.

Hematuria: The presence of blood in the urine.


  • Angiogram: An x-ray representation of blood vessels made after the injection of a radio-opaque dye. Used to visualize the inner layer of blood vessels, and to determine the location and degree of narrowing or dilation.
  • CAT Scan (CT scan): A Computerized Axial Tomography scan is an x-ray tube that rotates in a circle around the patient, making many pictures as it rotates. The multiple x-ray pictures are reconstructed by a computer in cross-sectional images, permitting doctors to examine “slices” through different organs. Catheterization: The insertion of a small plastic tube into a blood vessel, for the purpose of infusing fluid or radio-opaque dye (as in angiography), or for the purpose of sampling blood.
  • Chest X Ray: A chest x ray is a painless test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. Abnormal chest x-ray results may show whether vasculitis is affecting your lungs or your large arteries (such as the aorta or the pulmonary arteries).
  • MRI Magnetic Resonance Imaging: Another x-ray, similar to a CT scan. MRI scans also provide cross-sectional images of body organs. Because MRI technology involves the use of a large magnet, people with pacemakers, metallic aneurysm clips, and other metallic inserts are not eligible to have these studies.


Immune complex: Antibody and antigen bound together.

Immunoglobulins: A class of proteins present in the serum and cells of the immune system that function as antibodies.

Immunity: Body’s defense against foreign substances.

Immunosuppression: the partial or complete suppression of the immune response of an individual.

Incidence: The number of new cases of a disease in a population over a period of time.

Infarction: Localized necrosis resulting from obstruction of the blood supply. Myocardial infarction is another name for a heart attack.

Infection: Invasion by and multiplication of pathogenic microorganisms in part of the body, or in the body’s bloodstream.

Inflammation: Swelling, heat, and redness resulting from the infiltration of white blood cells in tissues.

Interferon: Protein that fights infection.

Ischemia: A decrease in the blood supply to an organ, tissue, or body part caused by constriction or obstruction of the blood vessels.

Jaw claudication: Pain in the jaw or ear while chewing. This is caused by insufficiency of the arteries supplying the jaw muscles, associated with giant cell arteritis.


Leukocyte: White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.

Lymph: Fluid collected from tissues that flows through lymph nodes.

Lymphocyte: Type of white blood cell that fights infection and mediates the immune response.

Mesenteric: Relating to folds of the peritoneum (the abdominal cavity) that connect the intestines to the abdominal wall, especially such a fold that envelops the small intestine.

Myalgia: Muscle pain.

Neutrophil: Granulated white blood cell involved in bacterial killing and acute inflammation.

Nephritis: Inflammation of the kidney.

Neuropathy: A disease or abnormality of peripheral nerves, the nerves that mediate sensation and movement in the arms, legs, and other body parts.

Neutropenia: The presence of abnormally few neutrophils in the blood, leading to increased susceptibility to infection.

Nodule: A small swelling or aggregation of cells in the body, especially an abnormal one.


Perforation: A hole in an organ, such as the gastrointestinal tract.

Perinuclear: Of or pertaining to a nucleus; situated around a nucleus. In some forms of vasculitis (e.g., microscopic polyangiitis), anti-neutrophil cytoplasmic antibodies (ANCA) cause perinuclear staining on immunofluorescence tests.

Petechiae: Small red spots under the skin.

Plasma: Fluid portion of blood.

Plasmapheresis: Filtration of blood plasma through a machine to remove proteins.

Pleura: Sac lining of the lung.

Pneumocystis pneumonia (PCP): A serious infection that causes inflammation and fluid buildup in the lungs.

Pneumonia: An acute or chronic disease marked by inflammation of the lungs and caused by viruses, bacteria, or other microorganisms. Forms of vasculitis that involve the lung are often misdiagnosed as pneumonia. Pneumonia is also a type of opportunistic infection that may occur in vasculitis patients under treatment.

Polymyalgia rheumatic: Autoimmune disease of the joints and muscles seen in older patients with high sedimentation rates who have severe aching in their shoulders, upper arms, hips, and upper legs.

Prevalence: The total number of cases of a disease present within a given population at a particular time.

Progressive multifocal leukoencephalopathy (PML): A rare and usually fatal viral disease characterized by progressive damage (-pathy) or inflammation of the white matter (leuko-) of the brain (-encephalo-) at multiple locations (multifocal).

Protein: Collection of amino acids. Antibodies are proteins.

Proteinuria: Excess protein levels in the urine.

Pulmonary hemorrhage: An acute bleeding from the lung, especially in the upper respiratory tract and the trachea.

Purpura: Hemorrhage into the skin.


Raynaud’s disease: Isolated Raynaud’s phenomenon; not part of any other disease.

Raynaud’s phenomenon: Discoloration of the hands or feet (they turn blue, white, or red), especially with cold temperatures; a feature of an autoimmune disease.

Remission: Remission means the absence of disease activity.

Renal failure: Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate, and your blood's chemical makeup may get out of balance. Chronic kidney disease, also called chronic kidney failure, describes the gradual loss of kidney function.

Retina: The innermost layer of the eye. Serves as the eye’s camera, transmitting images to the brain via the optic nerve.

Rheumatoid factor: Autoantibodies that react with Immunoglobulin G.

Ribonucleic acid (RNA): A nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins.

Scleritis: A type of inflammation that occurs in the sclera (white part of the eye) in some forms of vasculitis.

Subcutaneous: Underneath the skin. Some medications, for example, are injected under the skin.

Subglottic stenosis (SGS): A narrowing of the airway below the vocal cords (subglottis) and above the trachea.

Thiopurine methyltransferase (TPMT): A blood test for thiopurine methyltransferase (TPMT), which metabolizes thiopurine compounds such as azathioprine, helps identify patients at risk of toxicity from drugs like azathioprine. Most people have normal TPMT enzyme activity and respond well to normal doses of thiopurines. A small percent of people have one copy of a variant allele, or are severely deficient in TMPT, which results in an increased risk of drug toxicity.

Thrombocytopenia: Low platelet count.

Thrombosis: A blood clot.

Urinalysis: Analysis of urine. This test detects abnormal levels of protein or blood cells in the urine. Abnormal levels of these substances can be a sign of vasculitis affecting the kidneys.

Uveitis: Inflammation within either the anterior (front) or posterior (back) part of the eye.