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- a general term for several inflammatory diseases involving blood vessels (is synonymous w/ angiitis
- 2 types are immune-mediated or infectious vasculitis; it's important to distinguish between them to choose the appropriate therapy
Immune-mediated Vasculitides (Noninfectious Vasculitis)
can affect large (giant-cell arteritis), medium (polyarteritis nodosa), or small (microscopic polyangiitis, Wegener granulomatosis) vessels
What are the 4 main immunological mechanisms that initiate noninfectious vasculitis?
- 1. immune complex-associated vasculitis (due to antigens associated w/ viral infections, drug hypersensitivity, food, or unknown)
- 2. anti-neutrophil cytoplasmic antibodies (ANCAs: Abs directed against granules/parts of leukocytes aka against self)
- 3. antiendothelial cell antibodies
- 4. autoreactive T cells
Anti-neutrophil Cytoplasmic Antibodies(ANCAs)
- antibodies directed against constituents of neutrophil primary granules, monocyte lysosomes, & endothelial cells
- eg. anti-myeloperoxidase (MPO-ANCA, aka p-ANCA), anti-proteinase-3, (PR3-ANCA ,aka c-ANCA) etc.
Giant Cell (Temporal) Arteritis
- immune mediated, noninfectious granulomatous vasculitis
- most common form of vasculitis in elderly persons
- chronic, typically granulomatous inflammation of large-small arteries
- often seen in temporal arteries (also branches of the carotid, vertebral, ophthalmic, aorta, or other arteries)
- its cause is unknown, but may be due to a T cell-mediated immune response to an unknown antigen
- can be treated w/ steroids
Giant-Cell Arteritis Morphology
- nodular intimal thickening
- granulomatous inflammation
- fragmented internal elastic lamina
- segmental inflammation of an affected vessel (‘lumpy/patchy’)
Clinical Manifestations of Giant-Cell Arteritis
- rarely occurs in persons younger than 50 y/o
- malaise, fatigue, fever, weight loss, facial pain or headache
- temporal artery may be painful to palpation
- visual impairment with involvement of ophthalmic artery (can lead to blindness)
- elevated erythrocyte sedimentation rate
How is Giant-Cell Arteritis treated?
with corticosteroids or anti-TNF therapies
- a vasculitis of medium and small-sized arteries (typically involving renal & visceral vessels) which become swollen & damaged from attack by rogue immune cells ["systemic necrotizing immune complex inflammation"]
- is associated w/ chronic hepatitis B & HBsAg-HbsAb (antigen/antibody) complex in affected vessels
What kinds of vessels are NOT affected in Polyarteritis Nodosa?
- arterioles, capillaries, & venules are NOT affected, nor is the pulmonary circuit
- there is NO association with ANCAs
Clinical Aspects of Polyarteritis Nodosa
- manifests itself episodically; there can be long symptom-free intervals
- symptoms such as malaise, fever, weight loss, hypertension, abdominal pain, melena, diffuse muscular aches & pains, peripheral neuritis (especially in motor neurons) result from ischemia & infarction of affected tissues and organs
How is Polyarteritis Nodosa treated?
corticosteroids, cyclophosphamide, or other immunosuppression (can be fatal if untreated)
- autoimmune disease characterized by a systemic, pauci-immune, necrotizing, small-vessel vasculitis w/out clinical or pathological evidence of necrotizing granulomatous inflammation
- generally affects capillaries, arterioles, & venules smaller than those involved in Polyarteritis nodosa
- eg. hypersensitivity vasculitis, leukocytoclastic vasculitis, ANCAs-associated vasculitis
- necrotizing glomerulonephritis & pulmonary capillaries are particularly common
- a general term that refers to a form of vasculitis associated w/ minimal evidence of hypersensitivity & a lack of Anti-glomerular basement membrane antibody
- can be associated with antineutrophil cytoplasmic antibodies (ANCA)
Although the disease is not well understood, what is the hypothesized cause behind Microscopic Polyangiitis?
that it's antibody response to antigens such as drugs (penicillin), microorganisms (streptococci), heterologous proteins, or tumor proteins
What is the pathologies seen in the walls of vessels affected by Microscopic Polyangiitis due to?
recruitment & activation of neutrophils at those locations
How is Microscopic Polyangiitis treated?
immunosuppression drugs can induce remission except in cases where there is widespread renal or brain involvement
Wegener Granulomatosis (Granulomatosis with polyangiitis, GPA)
- necrotizing vasculitis w/ a triad
- 1. Granulomas of the upper (ear, nose, sinus, throat), lower (LUNG*) or both respiratory tracts
- 2. Vasculitis affecting small to medium-sized vessels (capillaries, venules, arterioles, arteries), most prominently in the lungs & upper respiratory tract
- 3. Renal disease in the form of focal necrotizing, often crescentic, glomerulonephritis
direct vascular invasion of fungal infections, septic emboli, syphilis, or rickettsial disease (to give a few examples)
- phlebitis (vein inflammation) related to a thrombus (blood clot in an intact vessel)
- systemic hypercoagulability often predisposes a person to thrombophlebitis
occurs when a blood clot in a superficial vein (SVT) forms independently from the presence of inflammation of the vein (phlebitis)
What is a serious complication of Deep Vein Thrombosis (DVT) & often its first manifestation?
- abnormally dilated, tortuous (full of twists & turns) veins caused by a prolonged increase in intraluminal pressure & a loss of vessel wall support
- if seen it typically occurs in superficial veins of the upper & lower leg (in 10-20% of adult males & 25-35% of females)
Varicose Vein Morphology
- wall thinning at the points of maximal dilation
- smooth muscle hypertrophy
- intimal fibrosis in adjacent segments
- elastic tissue degeneration
- spotty medial calcifications
- focal intraluminal thrombosis (due to stasis) & venous valve deformities are common
What causes Esophageal Varices to form?
portal hypertension, which leads to the opening of porto-systemic shunts, increasing blood flow into veins at the gastroesophageal junction forming esophageal varices (& hemorrhoids at the rectum) + periumbilical veins of the abdominal wall (caput medusa)
What can rupture of the esophageal varices lead to?
massive (potentially fatal) upper GI hemorrhage
- a benign tumor made of endothelial cells that line blood vessels, & is characterised by increased number of normal or abnormal vessels filled with blood
- 7% of all benign tumors of infancy & childhood are hemangiomas
- most are present at birth, increase in size initially, then regress spontaneously
- found on the head, neck, or internally (eg. liver)
- can be capillary (most common), juvenile, pyogenic, or cavernous (these do NOT spontaneously regress)
- malignant endothelial neoplasms that range from highly differentiated tumors resembling hemangiomas to wildly anaplastic lesions
- are most common in the skin, soft tissue, breast & liver but can be anywhere
- are associated w/ certain carcinogens (polyvinyl chloride, Thorostrast, arsenical pesticides)
- a tumor may appear years after exposure & invade locally & metastasize