Microscopic Polyangiitis

ANCA-associated necrotizing vasculitis affecting small vessels.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 9, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dahiliye (İç Hastalıkları) department. Book Appointment →

What is Microscopic Polyangiitis?

Microscopic polyangiitis (MPA) is a non-granulomatous, necrotizing vasculitis affecting small vessels. It belongs to the ANCA-associated vasculitis group and p-ANCA (anti-MPO) positivity is detected in 50-75% of cases.

The most common involvement is renal (necrotizing crescentic glomerulonephritis) and pulmonary (pulmonary capillaritis, alveolar hemorrhage). Unlike GPA, granuloma formation is not expected and upper respiratory tract involvement is rare.

Diagnosis is established with clinical presentation, serological tests (ANCA), and histopathological findings. Treatment is conducted similarly to GPA; induction and maintenance therapy are required.

Symptoms

Rapidly progressive renal failure

Hemoptysis and diffuse alveolar hemorrhage

Fever, weight loss, and fatigue

Arthralgia and myalgia

Cutaneous vasculitis (purpura, livedo reticularis)

Peripheral neuropathy (mononeuritis multiplex)

Risk Factors

Advanced age (peak incidence between 50-70 years)

Male gender (slight predominance)

Silica and other environmental exposures

Certain medications (hydralazine, minocycline, propylthiouracil)

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Rapidly worsening renal function and active urinary sediment
Hemoptysis and bilateral pulmonary infiltrates
Detection of p-ANCA positivity
Unexplained signs of systemic vasculitis

Treatment Methods

Induction: high-dose corticosteroid + cyclophosphamide or rituximab

Maintenance: azathioprine or rituximab

Plasmapheresis (in severe renal involvement or pulmonary hemorrhage)

Dialysis support in renal failure

Infection prophylaxis (TMP-SMX, antifungal)

Long-term relapse follow-up

Which Department to Visit?

You can visit our Dahiliye (İç Hastalıkları) department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Dahiliye (İç Hastalıkları) Department

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You can make an appointment with our specialists or contact us for your concerns.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.