Vasculitis
Vasculitis is inflammation of blood vessel walls.
Classification
Vasculitides can be classified by the size of the blood vessel that they predominantly affect.[1]
Large vessel vasculitis
The large vessel vasculitides are probably mediated by cellular immunity and generally have normal complement levels and no autoantibodies.[2][3] They are characterized histologically by giant cells.
Takayasu arteritis. Primarily affects the aorta and its main branches.
Giant cell (temporal) arteritis. Chronic vasculitis of both large and medium vessels, primarily affecting cranial branches of the arteries arising from the aortic arch.
Medium vessel vasculitis
The medium vessel vasculitides have similar pathology to the large vessel vasculitides.[3]
Polyarteritis nodosa. Systemic necrotizing vasculitis and aneurysm formation affecting both medium and small arteries. If only small vessels are affected, it is called microscopic polyangiitis, although it is more associated with Wegener's granulomatosis than to classic PAN.
Kawasaki disease. Usually in children, it affects large, medium, and small vessels, prominently the coronary arteries. Associated with a mucocutaneous lymph node syndrome.
Isolated CNS vasculitis. Affects medium and small arteries over a diffuse CNS area, without symptomatic extracranial vessel involvement. Patients have CNS symptoms as well as cerebral vasculitis by angiography and leptomeningeal biopsy.
Small vessel vasculitis
There are several vasculitides that affect small vessels.[4] Some small vessel vasculitides, "Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, and their localized forms (eg, pauci-immune necrotising and crescentic glomerulonephritis)," are associated with antineutrophil cytoplasmic antibodies.[5]
Antineutrophil cytoplasmic antibodies associated
Vasculitides associated with antineutrophil cytoplasmic antibody, with partial exception from microscopic polyangiitis, are associated with respiratory manifestations.[4] A systematic review of antineutrophil cytoplasmic antibody (ANCA) positive vasculitis identified best treatments depending on whether the goal is to induce remission or maintenance and depending on severity of the vasculitis.[6]
Wegener's granulomatosis. Systemic vasculitis of medium and small arteries, including venules and arterioles. Produces granulomatous inflammation of the respiratory tracts and necrotizing, pauci-immune glomerulonephritis. Most common cause of saddle nose deformity in USA (nose flattened due to destruction of nasal septum by granulomatous inflammation). Almost all patients with Wegener's have c-ANCA, but not vice versa.
Churg-Strauss arteritis. Affects medium and small vessels with vascular and extravascular granulomatosis. Classically involves arteries of lungs and skin, but may be generalized. The triad asthma, eczema and renal abnormalities (e.g., red blood cell casts in urine) should raise suspicion, calling for an eosinophil count. Eosinophilia, with this clinical presentation, is grounds for a preliminary diagnosis, but immunologic confirmation is needed.
Microscopic polyarteritis/polyangiitis. Affects capillaries, venules, or arterioles. Thought to be part of a group that includes Wegener's since both are associated with ANCA and similar extrapulmonary manifestations. Patients do not usually have symptomatic or histologic respiratory involvement.
Immune-complex associated
These vasculitides, with partial exception from microscopic polyangiitis, are associated with dermatological manifestations.[4]
Henoch-Schonlein purpura. Systemic vasculitis due to tissue deposition of IgA-containing immune complexes. Biopsy of lesions shows inflammation of small vessels. It is considered a form of hypersensitivity vasculitis but is distinguished by prominent deposits of IgA. This is the most common vasculitis in children.
Hypersensitivity vasculitis. Usually due to a hypersensitivity reaction to a known drug. There is presence of skin vaculitis with palpable petechiae or purpura. Biopsy of these lesions reveal inflammation of the small vessels, termed leukocytoclastic vasculitis, which is most prominent in postcapillary venules.
Essential cryoglobulinemic vasculitis. Most often due to hepatitic C infection, immune complexes of cryoglobulins --- proteins that consists of immunoglobulins and complement and precipitate in the cold while dissolving upon rewarming --- are deposited in walls of capillaries, venules, or arterioles. Therefore, complement will be low with histology showing vessel inflammation with immune deposits.
Vasculitis secondary to connective tissue disorders. Usually secondary to systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), relapsing polychondritis, Behce'ts disease, and other connective tissue disorders.
Vasculitis secondary to viral infection. Usually due to hepatitis B and C, HIV, cytomegalovirus, Epstein-Barr virus, and Parvo B19 virus.
References
- ↑ Jennette JC, Falk RJ, Andrassy K, et al (1994). "Nomenclature of systemic vasculitides. Proposal of an international consensus conference". Arthritis Rheum. 37 (2): 187-92. PMID 8129773. [e]
- ↑ Rabb H, Colvin RB (2007). "Case records of the Massachusetts General Hospital. Case 31-2007. A 41-year-old man with abdominal pain and elevated serum creatinine". N. Engl. J. Med. 357 (15): 1531–41. DOI:10.1056/NEJMcpc079024. PMID 17928602. Research Blogging.
- ↑ 3.0 3.1 Weyand CM, Goronzy JJ (2003). "Medium- and large-vessel vasculitis". N. Engl. J. Med. 349 (2): 160–9. DOI:10.1056/NEJMra022694. PMID 12853590. Research Blogging.
- ↑ 4.0 4.1 4.2 Jennette JC, Falk RJ (1997). "Small-vessel vasculitis". N. Engl. J. Med. 337 (21): 1512-23. PMID 9366584. [e]
- ↑ Bosch X, Guilabert A, Font J (2006). "Antineutrophil cytoplasmic antibodies". Lancet 368 (9533): 404–18. DOI:10.1016/S0140-6736(06)69114-9. PMID 16876669. Research Blogging.
- ↑ Bosch X, Guilabert A, Espinosa G, Mirapeix E (2007). "Treatment of antineutrophil cytoplasmic antibody associated vasculitis: a systematic review". JAMA 298 (6): 655-69. DOI:10.1001/jama.298.6.655. PMID 17684188. Research Blogging.