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Chapters
0:09 Introduction
0:03 Definition of Vasculitis
0:57 Causes of Vasculitis
1:23 Signs and symptoms of Vasculitis
3:00 Treatment of Vasculitis
Vasculitis is a group of disorders that destroy blood vessels by inflammation.[2] Both arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis.[3] Vasculitis is primarily caused by leukocyte migration and resultant damage. Although both occur in vasculitis, inflammation of veins (phlebitis) or arteries (arteritis) on their own are separate entities. Vasculitis can be classified by the cause, the location, the type of vessel or the size of vessel.
Underlying cause. For example, the cause of syphilitic aortitis is infectious (aortitis simply refers to inflammation of the aorta, which is an artery.) However, the causes of many forms of vasculitis are poorly understood. There is usually an immune component, but the trigger is often not identified. In these cases, the antibody found is sometimes used in classification, as in ANCA-associated vasculitides. Clinical studies with immunosuppressive drugs targeting specific cytokines and cells can also be used to understand the heterogeneous immunopathogenic mechanisms of vasculitis and support a mechanistic immunological classification.[5]
Location of the affected vessels. For example, ICD-10 classifies "vasculitis limited to skin" with skin conditions (under "L"), and "necrotizing vasculopathies" (corresponding to systemic vasculitis) with musculoskeletal system and connective tissue conditions (under "M"). Arteritis/phlebitis on their own are classified with circulatory conditions (under "I").
Type or size of the blood vessels that they predominantly affect.[6] Apart from the arteritis/phlebitis distinction mentioned above, vasculitis is often classified by the caliber of the vessel affected. However, there can be some variation in the size of the vessels affected.
A small number have been shown to have a genetic basis. These include adenosine deaminase 2 deficiency and haploinsufficiency of A20.
According to the size of the vessel affected, vasculitis can be classified into:[7][8]
Large vessel: Takayasu's arteritis, Temporal arteritis
Medium vessel: Buerger's disease, Kawasaki disease, Polyarteritis nodosa
Small vessel: Behçet's syndrome, Eosinophilic granulomatosis with polyangiitis, Cutaneous vasculitis, granulomatosis with polyangiitis, Henoch-Schönlein purpura, and microscopic polyangiitis. Condition of some disorders have vasculitis as their main feature. The major types are given in the table below: