What is vasculitis?

Vasculitis is the inflammation (swelling) of the body’s blood vessels. The condition occurs if your immune system attacks your blood vessels by mistake. Vasculitis can affect very small blood vessels (capillaries), medium-size blood vessels, or large blood vessels such as the aorta (the main blood vessel that leaves the heart).

What happens to the blood vessel in vasculitis?

When the blood vessel is inflamed, it may become weakened and result in structural disruption. Blood flow is impaired and blood clots may form in the inflamed vessels. Together with the swelling of the vascular walls, this effect may contribute to vessel narrowing or occlusion (blockage). Rarely, the vessels also may become thin and stretch in size, which can lead to aneurysms and rupture. This can result in bleeding into the tissue. The vessel wall itself becomes more "leaky," allowing the fluid from within the blood vessels to enter the surrounding tissues and causing swelling. These effects are both responsible for the various types of rashes and skin changes seen in this group of diseases. Involvement of the vessels supplying vital organs like the brain, kidneys, lungs or heart can compromise organ function and be a very serious condition.

What are the types of vasculitis? How is vasculitis classified?

Vasculitis classification in children is based on the size of the blood vessel involved.

  • Large vessel vasculitis, affects the aorta and its major branches.
  • Medium vessel vasculitis, affects arteries supplying the kidneys, bowels, brain or heart
  • Small vessel vasculitis, affects smaller blood vessels including capillaries in various organs

Some types of vasculitis diseases are quite common in children (e.g. Henoch-Schönlein purpura and Kawasaki disease), while the others are rare and their exact frequency is unknown.

What are the main symptoms of vasculitis?

Disease symptoms vary according to the overall number of inflamed blood vessels (widespread or just a few sites) and their location (vital organs like brain or heart versus skin or muscle) as well as the degree of blood supply compromise. This can vary from a transient minor decrease of blood flow to complete occlusion with subsequent changes to the unsupplied tissue caused by the lack of oxygen and nutrient supply. This can eventually lead to tissue damage with subsequent scarring.

Symptoms based on blood supply of organ involvement can include:

  • Brain : Alteration of consciousness, severe headache, stroke-like symptoms (paralysis)
  • Eyes: Blurred vision, seeing floaters, sensitive to light
  • Skin: Rash, chronic ulcer, bruise
  • Bowel: Abdominal pain, diarrhea, blood in stool
  • Lungs: Shortness of breath, coughing up blood
  • Kidneys: Kidney failure, decrease amount of urine, blood and protein leakage from kidney

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