Microscopic Polyangiitis

Division of Rheumatology, Department of Medicine, Rosalind Russell Medical Research Center for Arthritis, University of California, San Francisco, CA, USA.
Rheumatic diseases clinics of North America (Impact Factor: 2.69). 08/2010; 36(3):545-58. DOI: 10.1016/j.rdc.2010.04.003
Source: PubMed


In 1923, Friedrich Wohlwill described two patients with a "microscopic form of periarteritis nodosa," which was distinct from the classical form. This disease, now known as microscopic polyangiitis (MPA), is a primary systemic vasculitis characterized by inflammation of the small-caliber blood vessels and the presence of circulating antineutrophil cytoplasmic antibodies. Typically, microscopic polyangiitis presents with glomerulonephritis and pulmonary capillaritis, although involvement of the skin, nerves, and gastrointestinal tract is not uncommon. Treatment of MPA generally requires use of a cytotoxic agent (such as cyclophosphamide) in addition to high-dose glucocorticoids. Recent research has focused on identifying alternate treatment strategies that minimize or eliminate exposure to cytotoxic agents. This article reviews the history, pathogenesis, clinical manifestations, and treatment of MPA.

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    • "Pulmonary involvement occurs in 30-70% of MPA cases [11], with the classic pulmonary manifestation being diffuse alveolar hemorrhage caused by pulmonary capillaritis [2,13]. Some studies have suggested that subclinical intraalveolar hemorrhage may play a role in the development of pulmonary fibrosis in MPA [14-16]. "
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    ABSTRACT: Pulmonary involvement is a common feature of MPA. Although alveolar hemorrhage is the most common pulmonary manifestation of MPA, a few recent studies have described instances of MPA patients with pulmonary fibrosis. Pulmonary fibrosis was seen to predate, be concomitant with, or occur after the diagnosis of MPA. The goal of this study was to describe the clinical features and prognosis of microscopic polyangiitis (MPA) patients whose initial respiratory presentation was pulmonary fibrosis. We conducted a retrospective analysis of 19 MPA patients who presented with pulmonary fibrosis at Peking Union Medical College Hospital between 1990 and 2012. Of 67 total MPA cases, 19 patients presented with pulmonary fibrosis. There were 8 males and 11 females, with a median age of 63.6 years. Common clinical manifestations included fever (89.5%), cough (84.2%), dyspnea (78.9%) and velcro rales (84.2%). Eleven patients experienced weight loss, several had kidney involvement, and most had an increased erythrocyte sedimentation rate and C-reactive protein. All were positive for myeloperoxidase-anti-neutrophil cytoplasmic antibody (ANCA), with 6 patients being positive at the time of their initial diagnosis of pulmonary fibrosis. Every patient had typical features of usual interstitial pneumonia on High-resolution CT. All were treated with corticosteroids and cyclophosphamide, which lead to an improvement in twelve cases. One of the remaining patients progressed slowly, whereas six died. Patients with MPA, who also presented with pulmonary fibrosis in our cohort, were more likely to be older, female, and have extrapulmonic involvement. Most patients had a delayed positive ANCA. Corticosteroids plus cyclophosphamide was the remission-induction treatment scheme for all cases. The current prognosis for MPA patients with pulmonary fibrosis appears to be poor, suggesting that they may be candidates for new therapies.
    Full-text · Article · Jan 2014 · BMC Pulmonary Medicine
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    ABSTRACT: Die Differenzialdiagnose einer mikroskopischen Polyangiitis (mPA) bei Luftnot als Erstsymptom mit schwerem intensivmedizinischem Verlauf ist eine Rarität. Wir beschreiben den Fall eines 67-jährigen Patienten, der mit dem Bild einer schweren ambulant erworbenen Pneumonie mit progredienter Dyspnoe eingewiesen wird. Weitere Symptome waren Myalgien sowie Hauteffloreszenzen im Bereich der unteren Extremitäten. Er entwickelte im stationären Verlauf rasch ein „acute respiratory distress syndrome“ (ARDS) sowie ein dialysepflichtiges Nierenversagen. Der Nachweis der für eine mikroskopische Polyangiitis typischen Autoantikörper und das Ergebnis der Nierenbiopsie führten schließlich zur Einleitung einer spezifischen Therapie. Der Patient blieb unter immunsuppressiver Therapie im Verlauf dialysefrei.
    No preview · Article · Nov 2010 · Intensivmedizin + Notfallmedizin
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    ABSTRACT: We report two patients with rheumatoid arthritis (RA) who were suspected of microscopic polyangiitis during maintenance dialysis. Case 1 was a 52-year-old woman with RA diagnosed at the age of 38 years and treated successfully with gold compounds. At the age of 43 years, she presented with progressive renal dysfunction and abnormal urine sediments, and a renal biopsy revealed crescentic nephritis with advanced glomerular sclerosis. Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) was not measured on that occasion. She reached end-stage renal failure within 4 months and started peritoneal dialysis. Eight years later, soon after she was switched to hemodialysis, she developed fever of unknown origin. MPO-ANCA was elevated to 37 EU, although there were no other signs or symptoms suggestive of vasculitis. After taking prednisolone orally (10 mg/day), her fever withdrew, and MPO-ANCA became undetectable. Case 2 was a 71-year-old woman with RA diagnosed at the age of 60 years and treated with gold compounds. She developed renal failure of unknown cause (no biopsy was performed), and started hemodialysis at the age of 69 years. One year later, she presented with fever and subsequently developed cough with hemoptysis. MPO-ANCA was elevated to 62 EU. Treatment with azathioprine 50 mg and prednisolone 35 mg daily brought remarkable clinical improvement, and MPO-ANCA became undetectable. These cases highlight the importance of measuring ANCA even in RA patients on dialysis who present with fever of unknown origin or with underlying kidney disease of uncertain etiology.
    No preview · Article · Nov 2013
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