Microscopic polyangiitis presenting as pulmonary–renal syndrome in a patient with long-standing diffuse cutaneous systemic
Posted Mar 14 2011 10:47am
t has been suggested that systemic sclerosis (SSc) is primarily a disease of the vasculature . The associated vascular abnormalities are generally considered to be non-inflammatory and only rarely has a vasculitis been reported . Those patients in whom vasculitis has been diagnosed tended to have the limited cutaneous variant of SSc and features of Sjögren's syndrome .
Circulating antineutrophil cytoplasmic antibodies (ANCA) are considered to be markers of vasculitis, especially Wegener's granulomatosis, Churg–Strauss syndrome, and microscopic polyangiitis. Two types of ANCA have been shown to be useful for diagnosis: antimyeloperoxidase antibodies (anti-MPO), which produce a perinuclear pattern of staining by indirect immunofluorescence (pANCA), and antiproteinase 3 antibodies (anti-PR3), which produce a cytoplasmic pattern of staining (cANCA). Anti-MPO antibodies occur in a number of rheumatic diseases including rheumatoid arthritis, but their clinical significance is uncertain. A positive pANCA in SSc is rare, and an association with clinically evident vasculitis has been reported.
Two cases of diffuse cutaneous SSc associated with a pANCA-positive pulmonary–renal syndrome, a condition consisting of acute nephritis and lung hemorrhage, have been reported previously . Although the combination of prednisolone and cytotoxic drugs has been shown to be effective in a case of SSc-associated pANCA vasculitis , survival rate in pulmonary–renal syndrome associated with SSc is poor .
We describe a 43-year-old man with diffuse cutaneous SSc who survived a life-threatening pulmonary–renal syndrome caused by pANCA-positive vasculitis, and discuss the diagnostic and therapeutic issues that arose.