'Microscopic polyangiitis (MPA) ' is an ill-defined
autoimmune disease characterized by pauci-immune, necrotizing, small-vessel
vasculitis without clinical or pathological evidence of necrotizing
granulomatous inflammation. Because many different organ systems may be involved, a wide range of symptoms are possible in MPA.
Diagnosis
Laboratory tests show an increased
sedimentation rate, reduced
red blood count,
antineutrophil cytoplasmic antibodies (p-ANCA) directed against [MPO(a constituent of
neutrophil granules), and
protein and red blood cells in the
urine.
The test for
anti-glomerular basement membrane antibody (GBM), which is positive in
Goodpasture's syndrome, is negative.
Cause
This condition, the clinical picture of which may include many features of
systemic lupus erythematosis, has been reported to have been caused by
antibiotics and also by certain
infections, though, as with many autoimmune diseases, the causes remain to a large extent unknown.
Treatment
The customary treatment involves long term dosage of
prednisone, alternated or combined with
cytotoxic drugs, such as
cyclophosphamide or
azathioprine.
Plasmapheresis may also be indicated in the acute setting to remove ANCA antibodies.
See also
★
ANCA-associated vasculitides
★
Polyarteritis nodosa
External links
★
Overview at
Johns Hopkins
★
Overview at
Cleveland Clinic