Systemic vasculitis

Vasculitis is a heterogeneous group of diseases that are caused by inflammation of the vascular (mostly arterial) wall - angiitis. Histology, X-ray, is essential for diagnosis. According to the size of the affected vessel, we distinguish vasculitis into:


 * aortitis – aorta inflammation,
 * arteritis – inflammation of the middle and small arteries.
 * arteriolitis – inflammation of arterioles,
 * vasculitis – inflammation of arterioles, capillaries and venules,
 * phlebitis – inflammation of veins.

The result of vasculitis is weakening of the vascular wall (in some cases it arches as microaneurysms) with rupture and bleeding (petechiae to purpura – disorders of primary hemostasis), and also trombosis which occupies damaged intima, that was damaged by inflammations or obliteration of lumen in the repair of inflammation leading to ischemia.

Patogenesis

 * 1) Unclear etiopathogenesis (primary vasculitis), mostly autoimmune diseases, this can be one of the following mechanisms:
 * 2) *immunocomplexes and the inflammatory response triggered by them(immunopathological reaction type III.);
 * 3) *immunopathological reaction type IV.;
 * 4) *autoantibodies to lysosomal neutrophil enzymes (ANCA – Anti Neutrophil Cytoplasmatic Antibodies) – they stimulate neutrophils to the production of oxygen radicals and the secretion of lysosomal enzymes, which lead to damage to the surrounding tissue - the so-called pauciimmune type of reaction (without imumunocomplexes).
 * 5) Transition from the surroundings (flegmona, tuberculosis), septic embolus at central pyemia – secondary vasculitis.

Allergic vasculitis
Immune-related systemic inflammation of small blood vessels (arterioles, capillaries, venules) mainly in the skin, but also in other organs (brain, kidneys, GIT, lungs). These include vasculitis in:


 *  systemic connective tissue diseases (lupus erythematodes, rheumatoid arthritis etc.);
 * allergic reactions; to bacterial and viral antigens and to certain drugs (antibiotics…)
 * Henoch-Schönlein purpura – usually affects children and adolescents after an upper respiratory tract infection, affects the skin, kidneys, GIT, joints.


 * Patogenesis:Immunocomplexes are deposited in the vessel wall and activate complement. The chemotactic components of complement (C3a, C5a) attract neutrophils, which release lysosomal enzymes. These enzymes subsequently cause necrosis of the vascular wall.


 * Microskopically:Fibrinoid necrosis of vascular walls with neutrophil infiltration, breakdown of their nuclei (karyorhexis = leukocytoclassy) to form a chromatin powder in the lumen of a thrombosis vessel.

Polyarteritis nodosa (PAN)
It is an inflammation affecting all layers of the vascular wall (that is why polyarteritis) and aneurysms (that is why nodosa) that are formed segmentally. It was formerly referred to as periateritis because the inflammatory infiltrate extends far into the area around the vessel.


 * Patogenesis: The disease results from the formation of immunocomplexes that bind to the small and medium arteries. The causative antigen is very often hepatitis B virus). Immunocomplexes then "attack" the arteries of all tissues, especially the kidneys, GIT, heart, skeletal muscles, but omit the lungs. The disease occurs in attacks, so we find damage to the blood vessels of various ages. Complications of this disease include the formation of aneurysms as well as thrombosis, which can cause a heart attack.
 * Microscopially: Transmural fibrinoid necrosis firstly with polymorphocellular infiltrate (neutrophils), in later stages with round cell infiltrate (mononuclear cells). The infiltrate strikes periadventually. Inflammation heals with the help of ligaments and often obliterates the lumen.

Kawasaki disease
Pediatric PAN - mainly affects children under one year of age, in addition to vascular involvement it is characterized by skin rashes, conjunctivitis and oral mucosa inflammation, enlargement of lymph nodes (mainly cervical) - mucocutaneous and nodular syndrome, that is not very serious, it heals spontaneously, but there is a risk of coronary artery aneurysms (rupture) or thrombosis (heart attack).

Wegener's granulomatosis
Wegener's granulomatosis, more recently granulomatosis with polyangiitis, is probably autoimmune vasculitis (95% have been shown to be ANCA in serum patients), which is characterized by a triad:


 * PAN-type necrotising vasculitis, mainly affecting small blood vessels in the lungs;
 * necrotizing granuloma in the upper respiratory tract;
 * necrotizing glomerulonephritis (focal-segmental, sickle-shaped).

Churg-Strauss syndrome
Eosinophilic granulomatosis with polyangiitis (EGPA,Churg-Strauss syndrome) is a combination of necrotizing vasculitis that affects small to medium-sized blood vessels and eosinophilic granulomatosis, which mainly affects the respiratory tract and is largely similar to Wegener's granuloma. The disease is associated with eosinophilia and bronchial asthma and in 30-40% of cases also with the production of ANCA antibodies. .

Temporal arteritis (Horton's giant cell arteritis)
Segmental granulomatous inflammation of the upper and middle arteries(hlavně větví a.carotis externa et interna – a.temporalis superficialis, arteries of orbita (can lead to blindness), cerebral arteries (can lead to encefalomalacia). It mainly affects older women and it is sometimes associated with polymyalgia rheumatica.


 * Macroscopically: Reddening at temporal area, palpable pain, artery may turn into a stiff ligament.
 * Microscopically: At the beginning of lymphoplasmocytic infiltration, later formation of granulomas in the medium, disintegration of the internal elastic membrane and phagocytosis of its fragments by huge multinucleated cells), lumen thrombosis, chronic stage corresponds to repair - fibrosis of all wall layers and organization of the thrombus leads to obliteration of the lumen and transformation of the vessel into a fibrous band.

Takayasu's disease
Chronic idiopathic granulomatous aortitis, it also affects the receding large arteries (pulseless HK disease, vision disorders, neurological disorders), sometimes the lungs, mainly affects young women in Japan.


 * Macroscopically: Thickening of the wall, wrinkles and sclerosis of the intima to the occlusion of the lumen.
 * Microscopically: Lymphoplasmocytic and granulomatous inflammation of all layers of the wall, destruction of the elastic, scarring of the media, fibroproduction in the intima and adventitia, often thrombosis.

Bürger's disease(thrombangiitis obliterans)
Chronic inflammatory disease of the arteries and (deep) veins, especially in the lower limbs (a.tibialis), on the upper limb is most affected a.radialis, it affects younger smokers.

It starts as arteritis with thrombosis, the inflammation then passes to neighboring veins (including superficial veins - phlebitis migrans) and nerves. The inflammation is repaired and by organization of trombus is the whole nerve-vascular bundle is built into the fibrous band. The clinical symptoms are given by the occlusion of the artery - Raynaud's phenomenon (often the first symptom of the disease), claudication, gangrene.

Others
Other significant vasculitis are:


 * Microscopic polyangiitis.
 * Essential cryoglobulinemia.

Related links

 * Autoimmune diseases
 * Systemic vasculitis / case report

External sources

 * Vaskulitidy – video na youtube.com