Vasculitis

Vasculitis is the term used for a group of diseases characterized by the inflammation of and damage to the blood vessels or the blood vessel walls.

• The vascular system refers to the collection of all blood vessels in the body. Vasculitis is the term used for a group of diseases characterized by the inflammation of and damage to the blood vessels or the blood vessel walls. Vasculitis (plural vasculitides) can be a primary disease or a secondary condition related to another underlying disease.
• Different types of vasculitis have certain patterns of distribution that may affect particular organs, certain types of vessels, or specific vessel sizes. Vasculitis diseases affecting arteries are sometimes called arteritis, and those involving the veins are sometimes called venulitis. Overall, vasculitides (all types of vasculitis or vasculitic disorders) are uncommon conditions.
• In general terms, blood vessels can be divided into arteries, veins, and capillaries.
  • Arteries are the blood vessels carrying oxygenated blood from the lungs away from the heart to different organs.
  • Veins are blood vessels collecting the blood with less oxygen from the body organs in order to carry the blood back to the
  • heart to be pumped to the lungs where it receives oxygen.
  • The largest artery is the aorta coming out of the left side of the heart. The aorta divides into many smaller branches as it passes through the body, thus giving rise to arteries of different sizes. The small arteries (arterioles) then branch further into capillaries, which are very small blood vessels distributed diffusely within all organs of the body. The exchange of oxygen and waste products between the blood vessels and tissues happens at the level of the capillaries. These small blood vessels then coalesce (join together) to form small veins (venules) which give rise to larger and larger veins that eventually end up in the right side of the heart via the body's largest vein, the vena cava.

The signs and symptoms of vasculitis can be very vague, generalized, and non-specific. This is because of the complexity and variability of the different types of vasculitic diseases. It is also important to realize that vasculitis, as a whole, is a rare condition compared to other common conditions that may also cause similar signs and symptoms.

It may be safe to say that most of the signs and symptoms related to vasculitis are caused because the inflammation of the blood vessels results in an impaired or complete lack of blood flow to the specific organ(s) supplied by the affected blood vessels.

Examples of the symptoms and signs of the types of vasculitis include:

• CNS vasculitis may cause:
  • Headaches
  • Confusion
  • Focal neurologic problems.
• Churg-Strauss vasculitis can have symptoms similar to asthma because it involves the lungs.
• Henoch-Schonlein purpura. Purpura (small raised purple areas under the skin due to hemorrhage)
  • Abdominal pain
  • Nausea and vomiting
  • Joint pain
  • Blood in the urine (hematuria) because of its systemic involvement.
• Temporal arteritis may have headaches and tender, thick blood vessels on the side of the forehead.
• Cutaneous vasculitis may cause:
  • Purpura
  • Urticaria (hives)
  • Ulcers of the skin.

Vasculitis diseases, in general, are serious conditions and need to be evaluated promptly. The difficulty is that they may be difficult to recognize even by doctors because they are uncommon conditions that are not encountered routinely.

Typically, internal medicine doctors (internists), rheumatologists, dermatologists (skin doctors), eye doctors (ophthalmologists), lung doctors (pulmonologists), and kidney doctors (nephrologists) may recognize signs and manifestations of vasculitic diseases and may initiate the diagnostic evaluation for vasculitis conditions.

The causes of vasculitis diseases are largely unknown. Immunologic abnormalities (autoimmune disorders) seem to be the underlying cause of many vasculitic disorders, leading to inflammatory changes in the blood vessel walls.

Vasculitis diseases can involve certain blood vessel types or sizes. They may also involve certain organs. The most common classification system is based on blood vessel size.

Vasculitis affecting large blood vessels

Vasculitis affecting large blood vessels is called large vessel vasculitis and may include Takayasu arteritis and giant cell arteritis. Takayasu arteritis typically involves the aorta and its main branches. Giant cell arteritis or temporal arteritis generally affects the branches of the aorta that supply blood to the head.

Medium-vessel vasculitic disorders

• Polyarteritis nodosa (PAN). PAN classically affects the medium- to small-sized arteries, and it mainly involves the vessels of the kidneys (renal vasculitis) and the gut. A variation of this condition may affect smaller vessels and is called microscopic polyangiitis or microscopic polyarteritis. Some association exists between hepatitis B infection and PAN.
• Kawasaki disease. Kawasaki disease is a type of medium- and small-vessel vasculitis affecting the arteries of the heart (coronary arteries) in children. It is associated with a generalized febrile infection, which can cause vasculitis of the heart in the convalescence period of the illness.
• Vasculitis of the central nervous system (CNS vasculitis or cerebral vasculitis) is a rare disease characterized by inflammation of the arteries of the brain and the spinal cord. This condition may sometimes be associated with some viral infections, Hodgkin's disease, syphilis, and amphetamine use. In some instances, no underlying cause can be identified.

Small-vessel vasculitic diseases

There are several types of small-vessel vasculitis diseases.

• Churg-Strauss arteritis is an uncommon small-vessel disease that mainly affects the skin (cutaneous vasculitis) and the lung, although it rarely can involve other organs.
• Wegener's granulomatosis is a vasculitis of small arterioles and venules. It can affect many organs of the body (systemic vasculitis), but it usually involves the kidneys, the lungs (pulmonary vasculitis), and the upper respiratory tract (nasal cavity and sinuses). Certain antibodies (antineutrophil cytoplasmic antibodies or ANCA) are associated with Wegener's disease and may be detected in the blood of these patients.
• Henoch-Schonlein purpura is another small-vessel vasculitis that also affects many different organs (systemic vasculitis). This vasculitis is seen in infants, children, and adults, but it is more common in children between four to seven years of age.
• Hypersensitivity vasculitis is the term used for types of small-vessel vasculitis that may be related to an allergic insult to blood vessels. The main areas of involvement of these conditions are cutaneous (affecting the skin) as they damage the small vessels of the skin, and, therefore, they may also be called predominantly cutaneous vasculitis or cutaneous leukocytoclastic vasculitis.
• Essential cryoglobulinemia vasculitis is another type of rare small-vessel disease. Cryoglobulins are small protein complexes that can precipitate in cold temperatures. They may cause vascular inflammation by depositing in the vessel walls.

Some small-vessel vasculitis diseases can be related to an underlying rheumatologic disorder (connective tissue disorders), such as:

• Systemic lupus erythematosus (SLE) or lupus vasculitis
• Rheumatoid arthritis or rheumatoid vasculitis
• Behcet's disease
• Relapsing polychondritis. These conditions are typically confined to small vessels.
• Small- and medium-vessel vasculitis. Small- and medium vessel-vasculitis can also be caused by certain viruses. The most common viruses associated with vasculitis are:
  • Hepatitis B and C
  • Human immunodeficiency virus (HIV)
  • Cytomegalovirus (CMV)
  • Epstein-Barr virus
  • Parvovirus B19

Diagnosis of vasculitis may be challenging because of the significant overlap of signs and symptoms with other more common conditions. A careful medical history and a complete physical exam are the initial steps if the diagnosis of some type of vasculitis is suspected.

Depending on the organ that may be affected, certain laboratory tests and X-rays may be ordered. For example, routine blood work (complete blood count, electrolytes, and kidney and liver blood tests), urinalysis, and chest X-ray may be the basic diagnostic tests ordered. In general, some markers of vasculitis can be measured, which may provide additional supporting information in the evaluation of vasculitis. These tests include levels of ANCA, tests for specific viral infections, and markers of rheumatic diseases for lupus and rheumatoid arthritis.

Biopsy of an organ affected by vasculitis is essential in making or supporting the diagnosis of a vasculitis disease. The biopsy is typically done on the skin, kidneys, or lungs. A brain biopsy can be performed if brain vasculitis is suspected.

Angiograms are sometimes done to assess the physical appearance of blood vessels. This can be done by injecting a dye into the blood vessels and taking specific X-rays as it is traveling inside the vessels. This test may be useful in vasculitis involving larger blood vessels.

Vasculitis may be diagnosed upon the examination of the eyes by an eye doctor (ophthalmologist). Diagnosis of retinal vasculitis (vasculitis involving the retina or the inner surface of the eye) may trigger an investigation to find a systemic cause including lupus vasculitis, temporal arteritis, PAN, Wegener's disease, or Behcet's disease.

The medical treatment of vasculitis largely depends on the severity of the disease and the organs involved. In general, treatment is directed toward stopping or slowing the inflammatory process going on in the blood vessels.

The most common medications used to treat vasculitis are steroid-based anti-inflammatory medications (corticosteroids), such as prednisone.

Other immunologic medications may also be used in the treatment of vasculitis, such as

• cyclophosphamide (Cytoxan)
• azathioprine (Imuran, Azasan)
• methotrexate (Rheumatrex, Trexall).

It is very important for patients diagnosed with vasculitis to routinely follow up with their treating physician.

The response to treatment, routine evaluation of the markers of the disease, and assessment of affected organs are integral parts of follow-up care for vasculitis.

Perhaps, more importantly, evaluation of possible side effects of, or intolerance to, the strong medications used to treat vasculitis makes a routine follow-up with the physician essential.

Depending on the type of vasculitis and its response to the medication, the treating doctor sometimes may opt to taper the medications to a lower dose or completely discontinue the medications.

The overall prognosis for vasculitis depends on the severity of the condition and the underlying cause. Regardless of the type, prompt recognition, diagnosis, and treatment of these uncommon conditions carry a favorable prognosis.

• Because the majority of vasculitis conditions are auto-immune (the body's own immune system attacking the blood vessels), there may be no preventive measures.
• Some of the types related to infections or allergic reactions may be preventable if the infection is prevented or the allergic agent is avoided.