ANCA-associated vasculitis: GPA, MPA and EGPA explained

Vasculitis is inflammation of the blood vessels. The NHS explains that in vasculitis the immune system attacks healthy blood vessels, causing them to become swollen and narrow, and that this can range from a minor problem affecting only the skin to serious illness affecting organs such as the heart or kidneys.

ANCA stands for antineutrophil cytoplasmic antibody. Vasculitis UK describes microscopic polyangiitis as a vasculitis of the group of ANCA-associated vasculitides, typically inflaming small blood vessels, and names the other two as granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA). MPA differs from GPA and EGPA by lacking granulomatous inflammation.

These conditions are rare and potentially serious, and they are managed by specialist teams.

The NHS and Vasculitis UK describe each condition.

The NHS says symptoms of GPA vary between people, can be mild or severe, and may come on slowly over many months or suddenly. General symptoms may include a high temperature, night sweats, feeling weak and tired, joint pain, loss of appetite and weight loss. Others depend on the part of the body affected.

Vasculitis UK lists common MPA symptoms as tiredness, loss of appetite and joint and muscle aches, with specific symptoms by organ.

The NHS says to see a GP if you have symptoms of GPA, noting that some are very common and can be caused by other conditions but that it is important to get checked. If you have been diagnosed and have new or returning symptoms, see the specialist treating you.

Coughing up blood, new breathlessness, passing little urine or blood in the urine, sudden vision changes or severe symptoms of any kind should be treated as urgent, using NHS 111 or 999 as appropriate.

The NHS says there is no single test for GPA and it can be difficult to diagnose. A GP will ask about symptoms and may examine the affected part of the body, then refer to a specialist. Tests include a blood test for ANCA, a biopsy from affected body parts, X-ray, CT or MRI scans, and a urine test if the kidneys may be affected.

Vasculitis UK explains that it is important to recognise the pattern of symptoms, then, following clinical suspicion and a positive MPO ANCA test, confirm the diagnosis with a tissue biopsy, often a kidney biopsy where there is kidney disease. Lung manifestations are more likely to be assessed with high-resolution CT, sometimes with bronchoscopy. Teams discuss results in multidisciplinary meetings.

The NHS says there are 2 stages of treatment: bringing the condition under control and keeping it under control. For mild GPA, a steroid may be given with an immunosuppressant such as methotrexate. For severe GPA, a biological medicine such as rituximab or avacopan, or both, may be given with steroids, and sometimes cyclophosphamide.

Vasculitis UK says treatment has changed over the last years: steroids and cyclophosphamide used to be the main standard of therapy, rituximab has been shown to be as effective as cyclophosphamide in most cases, and avacopan is licensed for severe cases and may allow steroid minimisation. In overwhelming inflammation, plasma exchange may be added for a short while. Once the disease is under control, people remain on less intense immunosuppression, commonly rituximab or azathioprine, to avoid recurrence.

The NHS adds that if symptoms return (a relapse), treatment may be changed or restarted, and that in very severe cases affecting the kidneys you may need dialysis or a kidney transplant.

Vasculitis UK says the prognosis in MPA depends on disease severity and organ damage, that relapses are less likely in MPA but it can slowly and undetected scar kidney and lung tissue for a while, and that some people relapse but not all, so the need for prolonged treatment is checked to avoid overtreatment.

The NHS notes that your care team will pass information on to the National Congenital Anomaly and Rare Disease Registration Service (NCARDRS) and that you can opt out. For support and information, the NHS points to Vasculitis UK, including its living with vasculitis resources.

The NHS says you will be treated by a specialist if you have GPA, and Vasculitis UK says results are discussed in multidisciplinary team meetings.

Private specialist opinions are available. Because treatment involves long-term immunosuppression and monitoring, make sure test results and treatment plans are shared with your GP and treating team.