What are the two general types of vasculitis (aka angiitis)?
Immune-mediated and infectious
What are the four main mechanisms in immune-mediated vasculitis initiation?
- Immune-complex
- Anti-neutrophil cytoplasmic antibodies (ANCAs)
- Anti-endothelial cell antibodies
- Autoreactive T cells
What causes giant cell (Temporal) arteritis?
Immune-mediated. Possibly due to a T cell mediated immune response to an unknown antigen. Not completely understood.
In which vessels is giant cell (Temporal) arteritis often seen?
Small to large arteries: branches of the carotid such as the temporal branch, vertebral arteries, ophthalmic arteries, aorta.
Name six morphological changes associated with giant cell (Temporal) arteritis.
- Intimal thickening - reduced lumen diameter.
- Granulomatous inflammation.
- Multinucleated giant cells.
- Fragmentation of the internal elastic lamina.
- T cell infiltration (more CD4+ than CD8+).
- Affects segments of the vessel and lesions in the vessel can be in different stages - differentiates it from Microscopic polyangiitis.
What does a vessel that has healed from giant cell (Temporal) arteritis look like?
Scarring in the tunica media and intimal thickening. Residual elastic tissue fragmentation.
What is the diagnosis if a person older than 50 has a temporal artery that is dilated and painful to palpation?
giant cell (Temporal) arteritis
What vascular disease is associated with the following: Person older than 50 with history of recent malaise, fatigue, fever, weight loss, and visual impairment. ESR is elevated.
What is the treatment?
giant cell (Temporal) arteritis. Treat with steroids or anti-TNF.
What causes Polyarteritis Nodosa? What vessels does it affect?
Immune complexes, specifically Hep B immune complexes (HBsAg-HBsAB). Affects small and medium muscular arteries only.
Polyarteritis Nodosa affects vessels in which organ(s)? Where is it not typically seen?
Kidneys, visceral vessels but NOT pulmonary arteries.
Which vascular diseases are associated with ANCAs?
Microscopic polyangiitis, Wegener granulomatosis. Possibly giant cell (temporal) arteritis, too.
Which vascular disease is associated with the following conditions: malaise, fever, weight loss, hypotension, abdominal pain, melena (black stool associated with upper GI bleeding), diffuse muscle aches and pains, peripheral neuritis.
What happens if untreated? How is it treated?
Polyarteritis Nodosa. Fatal if untreated. Treat with steroids/immunosuppression.
Name morphological changes associated with Polyarteritis Nodosa.
- Fibrinoid necrosis is segmental.
- Only part of the vessel circumference is involved.
- All stages of activity can coexist (in the same or in different vessels) at the same time.
Describe the two phases of Polyarteritis Nodosa.
Early: Vessel wall has mixed infiltrate of polymorphs, eosinophils, and mononuclear cells. Often accompanied by fibrinoid necrosis.
Late: Fibrous thickening.
Hypersensitivity vasculitis, leukocytoclastic vasculitis, and ANCA-associated vasculitis are types of _______ ________.
Microscopic polyangiitis.
Which vessels are affected by Microscopic polyangiitis?
Capillaries, arterioles, and venules of the skin, mucous membranes, lungs, brain, GI tract, and muscle.
Most common: renal capillaries (necrotizing glomerulonephritis) and pulmonary capillaries
If lesions associated with vasculitis are all of the same age in a patient, what is the likely diagnosis?
Microscopic polyangiitis
What causes Microscopic polyangiitis? What likely association is commonly found?
Antibody response to antigens from drugs, microorganisms, foreign proteins, or tumor proteins. Anti-myeloperoxidase antibodies (MPO-ANCA) is found in 70% of patients.
Name five important points regarding the morphology of Microscopic polyangiitis.
- Segmental fibrinoid necrosis of the tunica media with focal transmural necrotizing lesions.
- Granulomatous inflammation is ABSENT.
- Microscopic infarcts are uncommon.
- Infiltrating and fragmenting neutrophils seen.
- Little or no Ig seen in most lesions.
Name the six clinical manifestations of Microscopic polyangiitis.
- Hemopysis (coughing up blood)
- Hematuria
- Proteinuria
- Bowel pain or bleeding
- Muscle pain or weakness
- Palpable cutaneous purpura
What is the triad of Wegener Granulomatosis?
- Granulomas of upper, or lower respiratory tract, or both.
- Vasculitis affecting SMALL TO MEDIUM vessels, mostly respiratory.
- Renal disease.
What other organs can Wegener Granulomatosis affect?
Eyes, skin, heart, other organs.
Name two cell types that are often found in a lesion from Wegener Granulomatosis.
- Multinucleate giant cells
2. Leukocytes
What is the diagnosis?
40 year old male. CXR shows bilateral pneumonitis with nodules and cavity lesions. He has mucosal ulcerations, chronic sinusitis, nasopharynx mucosal ulcerations, and renal disease.
Labs: CRP is elevated. anti-PR3 and C-ANCAs are present.
Biopsy: lesions with granulomas and geographic patterns of central necrosis and accompanying vasculitis.
Wegener Granulomatosis
What is the treatment for Wegener Granulomatosis? What if it is untreated?
Treatment is steroids, immunosuppresants like cyclophosphamide, TNF inhibitors. Disease is malignant and 80% die in one year if untreated.
What are the major complications of infectious vasculitis?
Artery walls weaken, can cause aneurysms or induce thrombus and infarction.
What is thrombophlebitis aka phlebothrombosis?
Venous thrombosis + inflammation
What is the biggest risk factor for DVT formation?
Prolonged immobilization
What is the most serious complication from DVT?
Pulmonary embolism
Which veins are affected in the condition of varicose veins? Can these develop a DVT?
Superficial ones, usually of the legs. DVTs from these are very uncommon.
Name seven morphological characteristics of a varicose vein.
- Dilation - wall thinning
- Smooth muscle hypertrophy
- Intimal fibrosis
- Elastic tissue degeneration
- Spots of calcification in the tunica media
- Focal intraluminal thrombosis due to stasis
- Valve deformities
What is the major cause of esophogeal varices?
Portal hypertension
What is a hemangioma?
Benign tumor of blood vessels
Are most hemangiomas that are present at birth initially get bigger, then spontaneously regress?
Yeah
On what three parts of the body are hemangiomas often found?
Head, neck, internally (e.g. liver)
What is the most common type of hemangioma? Where are they most often found?
Capillary hemangioma. Most often found on skin, subcutaneous tissues, mucous membranes of oral cavities and lips, liver, spleen, kidneys.
What is the composition of a capillary hemangioma?
Thin-walled capillaries, not much stroma.
Are juvenile hemangiomas common? Describe their growth rate.
Common: 1 in 200 births. They grow rapidly for a few months then fade by 1-3 years age.
What is another term for juvenile hemangioma?
Strawberry hemangioma
Pyogenic granulomas are a type of _________ _________ that present as lesions on _______, _______, or _______ mucosa. They bleed easily and are often ________.
They are a type of capillary hemangioma that present as lesions on skin, gingival, or oral mucosa. They bleed easily and are often ulcerated.
Describe a cavernous hemangioma.
Composed of large, dilated vessels separated by CT stroma. They infiltrate deeply and do not spontaneously regress.
What is an angiosarcoma? Describe the cellular composition of these.
Aggressive (30% 5-year survival rate) malignant endothelial neoplasms that range from highly differentiated tumors resembling hemangiomas to wildly anaplastic lesions.
In which parts of the body are angiosarcomas most common?
Skin, soft tissue, breast, liver.
What is thought to trigger the onset of an angiosarcoma?
Carcinogens such as PVC, Thorotrast (old XR contrast dye), and arsenical pesticides. Tumor appears years after exposure.
