Microscopic polyangiitis is a rare type of vasculitis that develops when inflammation affects blood vessels that interact with the lungs, kidneys, skin, nerves, and joints. The disease can cause many complications that damage and inhibit function at each location with which the blood vessels interact. While serious, microscopic polyangiitis is treatable.


Vasculitis refers to any blood vessel inflammation. As the inflammation progresses, the affected blood vessels can weaken and stretch, forming an aneurysm or becoming so thin that they rupture. They may also narrow, cutting off blood flow entirely. Microscopic polyangiitis affects a special antibody that attacks blood proteins, hence its classification as an ANCA-associated vasculitis.

vasculitis blood vessel inflammation gilaxia / Getty Images


Symptoms of Microscopic Polyangiitis

In addition to the general effects of vasculitis, microscopic polyangiitis has several unique symptoms that vary depending on the affected blood vessels. These include

  • Fever
  • Weakness
  • Tiredness
  • Joint and muscle aches
  • Ear pain or infections
  • Eye pain or sight impairment
  • Tingling and numbness resulting from nerve damage
  • Leg swelling and dark urine

Inflammation may also come and go, leading to fluctuating symptoms that seem to improve and then return. Though microscopic polyangiitis most commonly affects the kidneys, there may be no symptoms until the damage is severe. In some cases, people experience loss of kidney function without any signs.

fever weakness polyangiitis symptoms recep-bg / Getty Images



There is currently no known cause of microscopic polyangiitis. It does not seem to be inheritable and is not a form of cancer, nor contagious. Because the condition is ANCA-associated vasculitis, experts believe the immune system plays an important role in the development of microscopic polyangiitis. Experts think the immune system becomes overactive, causing the body to attack its blood vessels and tissues.

blood sample antibody AzmanL / Getty Images



Without treatment, microscopic polyangiitis can permanently damage the organs. Because it usually affects the kidneys, kidney failure is the most common complication. However, the condition can damage any organ that interacts with the inflamed blood vessels. Reports show breathing issues as microscopic polyangiitis damages the lungs. Signs of serious complications include dark or cloudy urine and coughing up blood.

kidney failure complication yezry / Getty Images


Affected Populations

Microscopic polyangiitis can affect people at any age. Evidence suggests that people around 50 years old are most at risk. Additionally, some studies show that males may be more likely to develop the condition than women. Though it can affect people of any ethnic background, it is more likely to develop in Caucasian individuals.

doctor patient older male Tinpixels / Getty Images



No specific test exists to diagnose microscopic polyangiitis. Instead, physicians consider several factors while performing a thorough medical history and physical exam. They may also use one or some of the following tests to confirm a diagnosis:

  • Blood tests to detect inflammation or ANCA antibodies
  • Urinalysis to discover kidney inflammation
  • Tissue biopsies to find damage or inflammation in the kidneys, lungs, skin, nerves, or muscles
  • X-rays, MRI scans, or CT scans

mri scan diagnosis process gilaxia / Getty Images


Treatment Process

Once an expert confirms that a patient has microscopic polyangiitis, they create a treatment plan specific to the symptoms, severity, and progression of the condition. The ultimate goal of treatment is to prevent organ damage. Even with treatment, relapses occur in 30 to 50% of cases. This means that completely curing a person is not realistic, though a significant number of people do achieve complete remission. After a relapse, ongoing treatment helps many people achieve remission again.

treatment process plan doctor DjelicS / Getty Images



Treatment usually begins with steroids to reduce overall inflammation. Once the swelling improves, doctors move on to immunosuppressants to control inflammation and prevent the antibodies from attacking the body. The first round of immunosuppressants usually takes three to six months. As the medications reduce inflammation, doctors begin to lower the dosage. This period of lower doses lasts between 12 and 18 months and helps prevent microscopic polyangiitis from relapsing. Physicians use antibiotics throughout the treatment process to prevent unwanted infections.

medication steroid treatment immunosuppressant SDI Productions / Getty Images



Most people with microscopic polyangiitis have positive outcomes, but it is still important to remain vigilant for any signs of relapse and maintain regular contact with a doctor, who can help watch for complications and any side effects of medication. An active lifestyle with a healthy diet can help prevent relapse and reduce inflammation. Some physicians may recommend lifestyle coaches, counselors, or dieticians to help patients build healthy habits.

positive outlook exercise healthy FluxFactory / Getty Images


Granulomatosis with Polyangiitis

Some doctors confuse microscopic polyangiitis with a similar and related form of vasculitis, granulomatosis with polyangiitis. While the two conditions are remarkably alike, there are key differences. Notably, the latter has a characteristic symptom: the inflammation begins to grow granulomas, benign growths that typically appear in the lungs, though they can develop elsewhere.

confuse doctor diagnosis Portra / Getty Images


Popular Now on Facty Health


This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.