Pathology of Vasculitis Flashcards
What is vasculitis?
a group of disorders that destroy blood vessels by inflammation
What things are important to keep in mind when considering vasculitis?
size (large, small) and type of vessel (artery, vein)
sex, age, ethnicity
clinical features (renal, GI symptoms)
histology
immune complexes
anti-neutrophil cytoplasmic antibodies: ANCA
anti-endothelial cell antibodies
If there are immune complexes associated with vasculitis, what will you see?
immune reactants and complement detected in serum or vessels.
What immune complexes will be found in systemic lupus erythematous (SLE)?
DNA-anti-DNA complexes found in vessels
Can hypersensitivities to drugs cause vasculitis?
YES
Can vasculitis be associated with viral infections?
YES
**What are anti-neutrophil cytoplasmic antibodies (ANCAs)?
group of antibodies that are formed against enzymes in the azurophil or primary granules in neutrophils, lysosomes of monocytes, and in endothelial cells due to defects in immune regulation. Titers reflect clinical severity. The etiology (cause) may be linked to neutrophils activated by ANCAs.
In what diseases are anti-neutrophil cytoplasmic antibodies (ANCAs) seen?
SLE and Kawasaki disease
Can ANCAs directly activate neutrophils?
YES, stimulating release of ROS and proteolytic enzymes. It is this activation that can cause destructive interactions between inflammatory cells and endothelial cells.
What are the 2 types of vasculitis?
- Anti-proteinase 3 (PR3-ANCA, formerly c-ANCA)= cytoplasmic localization of staining target antigen being proteinase 3 (PR3).
- Anti-myeloperoxidase (MPO-ANCA, formerly p-ANCA)= perinuclear staining specific for MPO
* Some vasculitis will be positive for both and some will be negative for both of these ANCAs.
What is polyarteritis nodosa (PAN)?
inflammation of many medium sized arteries with some nodularity to them. Renal and GI involvement is common. The pulmonary vessels are spared however.
How does polyarteritis nodosa present?
as acute, subacute, or chronic lesions with hypertension (renal involvement), wt. loss, fatigue, abdominal pain, GI hemorrhage, and melana (dark sticky feces) in young adults.
Will also see elevated ESR and leukocytosis (increase in WBCs).
Renal involvement is usually cause of death.
Does polyarteritis nodosa affect just segments of arteries?
YES, but it is transmural (entire thickness of wall) necrotizing inflammation. Early lesions are fibrinoid that cause fibrous thickening of the vessel wall.
** What is important to remember about stages of polyarteritis nodosa?
All stages coexist in different vessels or the same vessel!
Is the glomerulus involved in polyarteritis nodosa (PAN)?
NO! This is a small vessel, and even though the kidney is involved, it only affects MEDIUM vessels.
**For what antigen are many people with polyarteritis nodosa positive?
(board question)
Hepatitis B antigen
Is there an association with c-ANCA in polyarteritis nodosa?
NO!
What happens to a vessel when it becomes injured?
It becomes pro-thrombotic with mixed inflammatory infiltrates
Where specifically within the vascular system will PAN commonly affect?
arterial branch points