Receiving a diagnosis of microscopic polyangiitis (MPA) can be confusing and frightening. This rare autoimmune condition causes blood vessels to become inflamed and damaged, affecting vital organs like the kidneys and lungs. Patients often experience vague but persistent symptoms such as exhaustion, fever, weight loss, or muscle aches before a diagnosis is confirmed. The uncertainty of the condition can disrupt daily life and create anxiety about long-term health. However, with prompt medical intervention, the outlook for MPA has improved significantly in recent years.

Treatment is critical to stop the inflammation immediately and prevent permanent organ failure, particularly kidney damage. The primary goal is to achieve remission, a state where the disease is inactive and then maintain that state to prevent relapses. Because MPA affects multiple body systems, treatment plans are often complex and tailored to the individual. Doctors consider the severity of organ involvement and the patient’s age and overall health when selecting a medication regimen (Vasculitis Foundation, 2023).

Overview of treatment options for Microscopic Polyangiitis

The treatment strategy for MPA is typically divided into two distinct phases: induction and maintenance. The induction phase is an aggressive period of treatment intended to stop the active disease quickly and save organ function. Once remission is achieved, usually within a few months, treatment shifts to the maintenance phase, which uses less potent medications to keep the disease suppressed over the long term.

Medical management relies heavily on immunosuppressive drugs. These medications calm the overactive immune system that is attacking the blood vessels. In severe cases, plasma exchange (plasmapheresis) may be used temporarily alongside medication to remove harmful antibodies from the blood, though this is less common than drug therapy alone.

Medications used for Microscopic Polyangiitis

For the induction phase, high doses of corticosteroids, such as prednisone, are almost always prescribed initially to rapidly reduce inflammation. These are typically combined with a powerful immunosuppressant. The two standard first-line options are rituximab and cyclophosphamide. Clinical studies suggest that rituximab is as effective as cyclophosphamide for inducing remission but may be preferred for certain patients to preserve fertility or avoid specific side effects.

For the maintenance phase, once the disease is under control, doctors transition patients to milder medications. Common options include azathioprine, methotrexate, or mycophenolate mofetil. In some cases, rituximab is used on a scheduled basis for maintenance as well.

A newer medication, avacopan, has recently been approved as an add-on therapy. It is used specifically to help reduce the reliance on high-dose steroids, sparing patients from some of the harsh side effects associated with long-term steroid use. Patients can generally expect symptoms to improve within weeks of starting induction therapy, though full remission may take several months (American College of Rheumatology, 2021).

How these medications work

Corticosteroids broadly suppress the immune system and block inflammation-triggering substances, acting as a “fire extinguisher” for widespread blood vessel inflammation.

Rituximab targets B-cells, depleting those responsible for producing the harmful antibodies (ANCAs) that attack blood vessels in MPA, thus stopping the attack.

Cyclophosphamide interferes with the DNA replication of rapidly dividing cells, halting the proliferation of damaging immune cells. Avacopan blocks the C5a receptor in the complement system to reduce inflammation and vessel damage without broadly suppressing the immune response (National Institute of Diabetes and Digestive and Kidney Diseases, 2022).

Side effects and safety considerations

Because these medications suppress the immune system, the most significant risk is infection. Patients face increased risk of bacterial/viral illness and may need prophylactic antibiotics.

Corticosteroids can cause weight gain, high blood sugar, mood changes, and osteoporosis. Cyclophosphamide risks bladder irritation and potential infertility, making rituximab often preferred for younger patients. Regular blood/urine tests are vital to monitor kidney function and white blood cell counts.

Patients must seek immediate care for high fever, signs of infection, or blood in the urine. Pregnancy requires careful planning as many medications are teratogenic. Since everyone’s experience with the condition and its treatments can vary, working closely with a qualified healthcare provider helps ensure safe and effective care.

References

1. American College of Rheumatology. https://www.rheumatology.org
2. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov
3. Vasculitis Foundation. https://www.vasculitisfoundation.org
4. Mayo Clinic. https://www.mayoclinic.org