Systemic Vasculitis: Causes, Symptoms, and Treatment

Systemic vasculitis is a group of uncommon autoimmune disorders involving inflammation of the blood vessels. This inflammation can cause blood vessel walls to thicken, narrow, weaken, or develop scarring. These changes restrict blood flow, leading to potential organ and tissue damage. The condition ranges from mild cases affecting a single organ to severe presentations involving multiple body systems.

Underlying Causes and Triggers

In most cases, the specific cause of vasculitis is unidentified and is referred to as primary vasculitis. The condition occurs when the body’s immune system incorrectly targets its own blood vessel cells. This autoimmune attack initiates an inflammatory response within the vessel walls, leading to the structural changes and blood flow issues characteristic of the condition.

Certain factors are recognized as contributors to secondary vasculitis, where a specific trigger is present. Infections, such as hepatitis B and C, are known triggers for some forms of the disease. Reactions to certain medications can also provoke an episode, and vasculitis can arise in individuals with other autoimmune diseases like rheumatoid arthritis or lupus.

Classification of Vasculitis Types

Systemic vasculitis is an umbrella term for many different conditions. Physicians classify these disorders based on the size of the blood vessels primarily affected. The main categories are large-vessel, medium-vessel, and small-vessel vasculitis.

Large-Vessel Vasculitis

This category includes conditions affecting the aorta and its largest branches. Giant cell arteritis (GCA) is an example, typically affecting adults over 50 and involving arteries in the head and neck. Takayasu’s arteritis is another type that primarily affects younger women, causing inflammation of the aorta and its major arteries.

Medium-Vessel Vasculitis

Medium-vessel vasculitides target arteries and veins distributing blood to various organs. Polyarteritis nodosa (PAN) can affect the skin, kidneys, and nerves by damaging their supplying arteries. Kawasaki disease is another type, seen primarily in young children, causing inflammation in arteries throughout the body, including the coronary arteries.

Small-Vessel Vasculitis

This group involves inflammation of the body’s smallest blood vessels. A subgroup is the ANCA-associated vasculitides, named for the presence of anti-neutrophil cytoplasmic antibodies. This includes Granulomatosis with Polyangiitis (GPA), which affects the sinuses, lungs, and kidneys. IgA vasculitis is the most common form in children and is characterized by a skin rash, joint pain, and potential kidney involvement.

Common Symptoms and Affected Organs

The signs of systemic vasculitis vary depending on which blood vessels and organs are involved. Many people first experience general symptoms common to inflammatory conditions, including:

  • A persistent fever
  • Unexplained fatigue
  • Loss of appetite and weight loss
  • Aches in the muscles and joints

Symptoms become more specific as organ systems are affected. Inflamed skin vessels can lead to rashes, purple spots, or painful ulcers. Kidney involvement may cause changes in urination, such as blood in the urine. Lung inflammation can cause shortness of breath or a cough that may produce bloody phlegm.

Neurological involvement can manifest as numbness, weakness, or tingling in the hands and feet from nerve damage. In some cases, vasculitis can affect the brain, leading to a stroke. It can also affect the heart, causing chest pain.

The Diagnostic Process

Diagnosing systemic vasculitis can be complex because its symptoms often mimic other illnesses. A physician begins with a physical examination and a detailed review of the patient’s medical history. The diagnosis relies on a combination of laboratory tests, imaging studies, and sometimes a tissue sample.

Blood and urine tests are common first steps. Blood tests can reveal general markers of inflammation, such as an elevated C-reactive protein. More specific blood tests can identify autoantibodies like ANCA, which are associated with certain small-vessel vasculitides. Urine tests check for signs of kidney involvement, such as red blood cells or protein.

Imaging tests help visualize blood vessels and assess organ damage. An angiogram, an X-ray using a special dye, can reveal narrowing or blockages. Other methods like CT scans or MRIs can show changes in organs supplied by inflamed vessels. A biopsy is often the most definitive tool. This involves removing a small piece of tissue from an affected blood vessel or organ to be examined under a microscope for signs of inflammation.

Management and Therapeutic Approaches

Treatment for systemic vasculitis focuses on controlling acute inflammation to achieve remission and then maintaining it to prevent relapses. The therapeutic approach depends on the type of vasculitis and the severity of organ involvement. While there is no cure, management centers on controlling the disease and its symptoms.

The initial phase of treatment often involves high doses of corticosteroids, like prednisone, to induce remission. These powerful anti-inflammatory agents quickly reduce blood vessel inflammation and alleviate symptoms. They can be administered orally or, in severe cases, intravenously for a more rapid effect.

For long-term control, other medications that modify the immune system are used. Immunosuppressant drugs, such as methotrexate or azathioprine, address the underlying autoimmune attack. More recently, biologic drugs like rituximab have become an option for certain types of vasculitis. These therapies target specific cells or proteins involved in the inflammatory process.

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