NYU Langone rheumatologists use various diagnostic tools to help them diagnose vasculitis, which is an autoimmune disorder that causes inflammation of the blood vessels. If a blood vessel is inflamed, it can narrow or close off, restricting or even preventing blood flow. Rarely, an inflamed blood vessel can stretch and weaken, causing an aneurysm, which is a balloon-like bulge in the wall of the blood vessel that can burst and cause serious, even life-threatening, bleeding.
Vasculitis occurs when the body’s immune system attacks the blood vessels by mistake. This autoimmune attack may happen as a result of an infection, due to certain medications, or because of another health condition.
Vasculitis can affect the body in many different ways, and symptoms vary by the size, type, and location of the affected blood vessels. Vasculitis affecting the lungs, for instance, can cause asthma, whereas vasculitis affecting the kidneys can cause kidney failure.
Some types of vasculitis are more likely to occur in people who have certain medical conditions, such as hepatitis B or C, or people with other autoimmune disorders, such as lupus, rheumatoid arthritis, and scleroderma.
Diagnostic Tests for Vasculitis
To diagnose vasculitis, your doctor takes a medical history, asks about your signs and symptoms, conducts a physical exam, and orders laboratory tests. Because the disease can affect different organs, a rheumatologist may want to perform several diagnostic tests, based on your symptoms, to determine the best treatment plan for you.
CT scans provide detailed images of tissue and internal organs. This imaging test is often used by your doctor to look for vasculitis damage in the abdomen.
Your doctor may order an MRI scan to better view your internal organs. MRI uses magnetic waves and computers to create two- or three-dimensional images of the inside of the body. An MRI scan can help a doctor see if the blood vessel walls are thickened, particularly in the large vessels, which may signal reduced blood flow and tissue damage.
To look for signs of tissue or organ damage, your doctor may perform a biopsy. In this procedure, your doctor takes a small sample of the affected area—for example, part of the temporal artery, skin, or an organ, such as the kidney or lung—and studies the features of its cells under a microscope. A biopsy is helpful for identifying types of small vessel vasculitis and medium vessel vasculitis.
Your doctor may order a blood test to determine if you have medium or small vessel vasculitis, which can be caused by antineutrophil cytoplasmic antibodies. The immune system makes antibodies to attack foreign objects, but antineutrophil cytoplasmic antibodies mistakenly attack a certain type of white blood cell, damaging small blood vessels. The test can tell your doctor if these proteins are present in your blood and, if so, to what extent.
Blood tests reveal other markers of inflammation or the specific type of vasculitis causing your symptoms. They are used to rule out other conditions that can cause vasculitis and are treated separately, such as an infection or blood cell cancers, including leukemia or lymphoma.
If you have heart symptoms, such as heart attack or pressure in the chest, your doctor may order an echocardiogram, an imaging test that uses sound waves to create a live picture of your heart. The moving pictures show the size, shape, and structure of your heart and can help your doctor to determine if your heart is working properly.
An electrocardiogram, or EKG, is a tool used to record electrical activity in the heart. People with vasculitis can develop inflammation in the coronary artery, producing chest pain and possibly leading to a heart attack. If you have chest pain or shortness of breath, or your doctor thinks vasculitis is affecting your heart, he or she may order an EKG to see how well your heart is functioning.
Your doctor may use ultrasound to evaluate the soft tissues of the body, such as the organs in the abdomen. An ultrasound machine bounces high-frequency sound waves off parts of an organ or tissue and captures the returning “echoes” as images.
Your doctor may ask for a urine sample to check for any abnormal levels of proteins or blood cells in the urine, which could be a sign of small vessel vasculitis in the kidneys.
To get a better picture of the arteries or veins, your doctor may order a specialized X-ray test called angiography. In this test, dye is injected into the bloodstream and travels through the blood vessels, creating visual contrast to help your doctor determine if there is a blockage in the arteries or veins in the head, chest, arms, legs, back, or abdomen. Angiography is helpful in identifying medium and large vessel vasculitis.
An X-ray of your chest can show your doctor if vasculitis is affecting your heart, lungs, or large arteries.