07-07-2025
Fast Five Quiz: Management of MPA
Microscopic polyangiitis (MPA) represents one category within the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), alongside granulomatosis with polyangiitis (GPA) and eosinophilic GPA (EGPA). MPA is associated with distinct presentations, organ involvement, and worse prognosis than EGPA and GPA; treatment strategies must be customized according to disease severity, affected organs, and individual patient characteristics.
What do you know about the management of MPA? Check your knowledge with this quick quiz.
Although renal involvement is common in ANCA vasculitis owing to a high concentration of blood vessels, subtypes of ANCA vasculitis have distinct patterns of extrarenal involvement. These varying clinical presentations correlate with different antibody profiles: MPA commonly associates with myeloperoxidase (MPO) serology while GPA generally presents with proteinase 3 (PR3) serology. Following renal involvement, the pulmonary system is a commonly involved organ system in MPA; cutaneous involvement and neurologic manifestations are also common. MPA typically shows fewer manifestations in the ear, nose, and throat region and eyes than other subtypes. Cardiovascular system and gastrointestinal system involvement are more often seen in EGPA, though patients with MPA can experience cardiovascular and gastrointestinal symptoms.
Learn more about renal involvement in MPA.
The latest Kidney Disease Improving Global Outcomes (KDIGO) and European Alliance of Associations for Rheumatology (EULAR) guidelines recommend beginning plasma exchange in patients with MPA when serum creatinine rises above > 300 µmol/L (equivalent to 3.4 mg/dL, as stated by KDIGO). This is supported by a recent meta-analysis that reported plasma exchange reduces the risk for end-stage kidney disease at 12 months; the same serum creatinine level for initiation was recommended by the researchers. However, they noted that plasma exchange was not found to improve the combined endpoint of "death and/or end-stage kidney disease."
Additionally, KDIGO also recommends plasma exchange for patients requiring dialysis or those with diffuse alveolar hemorrhage and hypoxemia, but EULAR specifically recommends against routine use of plasma exchange for diffuse alveolar hemorrhage in patients with MPA and GPA.
Learn more about creatinine monitoring in MPA.
The latest KDIGO guidelines recommend considering discontinuation of immunosuppressive therapy in patients with MPA who have remained on dialysis for 3 months without extrarenal disease manifestations. This approach acknowledges that patients with MPO-ANCA-associated vasculitis (which is most strongly associated with MPA) who have kidney failure without involvement of other organs face minimal relapse risk. Supporting this, the EULAR cites research demonstrating that patients who are dependent on dialysis and in remission without immunosuppression are significantly more likely to experience serious infectious or cardiovascular complications from continued treatment than suffer disease recurrence; they specifically recommend weighing benefits and harms in continuing immunosuppressive therapy in the MPA subtype of ANCA.
Learn more about immunosuppressive therapy in MPA.
According to a recent review citing data from KDIGO, patients with MPA typically have the worst kidney prognosis due to the chronic damage associated with this subtype. Further, patients with EGPA less often have kidney involvement than GPA or MPA and usually have better kidney prognosis. Kidney prognosis is generally worse in patients with MPA than those with GPA as well.
KDIGO also cites previously developed prognostic scoring systems (which include sclerotic, focal, crescentic, and mixed class), depending on most of the glomeruli histology. For example, focal class (> 50% normal glomeruli) is associated with a favorable outcome, while sclerotic class (≥ 50% sclerotic glomeruli) is associated with poorer outcomes.
Learn more about prognosis in MPA.
Both KDIGO and EULAR guidelines recommend a tapering schedule of 4-5 months after initiating glucocorticoids in patients with MPA, reaching a reduced dose (listed as " 5 mg prednisolone equivalent" per day) by that point. Tapering schedule is generally based on weight and disease severity. For example, for patients weighing > 75 kg (165 lb), EULAR suggests starting at 75 mg, then tapering to 40 mg by week 2, then lowering the dose by approximately 25% every 2 weeks until reaching 5 mg by week 19. This is the same tapering schedule recommended by KDIGO; the full tapering schedule for this weight and others can be found here.
Clinical evidence supporting this strategy comes from the PEXIVAS trial, which demonstrated that lowering steroid exposure by 40% during the initial 6 months maintained therapeutic effectiveness while significantly decreasing serious infection rates compared to conventional dosing. This accelerated reduction strategy effectively balances inflammatory control with minimizing steroid-related complications.
Learn more about glucocorticoids in MPA.
