Microscopic polyangiitis

Microscopic polyangiitis (MPA) is a disorder that causes blood vessel inflammation (vasculitis), which can lead to organ damage. The kidneys, lungs, nerves, skin, and joints are the most commonly affected areas of the body. MPA is diagnosed in people of all ages, all ethnicities, and both genders.The cause of this disorder is unknown.

Cause

The cause of MPA is unknown. It is not contagious, does not usually run in families, and is not a form of cancer. The immune system is thought to play a critical role in the development of MPA. It is thought that the immune system becomes overactive and causes blood vessel and tissue inflammation, which leads to organ damage. It is not known what causes the immune system to become overactive.

Symptoms

The symptoms of MPA depend on which blood vessels are involved and what organs in the body are affected. The most common symptoms of MPA include kidney inflammation, weight loss, skin lesions, nerve damage, and fevers.Other symptoms depending on the area(s) of the body affected may include:

• Skin-Rash
• Lungs-cough, breathing problems, spitting up blood.
• Gastrointestinal-bleeding in the gastrointestinal tract, abdominal pain.
• Brain/neurological-tingling, pain, weakness, loss of sensation, seizures.
• Musculoskeletal-joint pain, muscle pain.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Autoimmunity(Autoimmune disease)
• Erythema
• Fever
• Glomerulopathy
• Hematuria(Blood in urine)
• Hemoptysis(Coughing up blood)
• Oliguria
• Renal insufficiency(Renal failure)
• Skin rash
• Vasculitis(Inflammation of blood vessel)

30%-79% of people have these symptoms

• Abdominal pain(Pain in stomach)
• Arthralgia(Joint pain)
• Diarrhea(Watery stool)
• Gastrointestinal hemorrhage(Gastrointestinal bleeding)
• Gastrointestinal infarctions(Death of digestive organ tissue due to poor blood supply)
• Myalgia(Muscle ache)
• Nausea and vomiting
• Peritonitis
• Skin ulcer(Open skin sore)
• Subcutaneous hemorrhage(Bleeding below the skin)
• Venous thrombosis(Blood clot in vein)

Diagnosis

Laboratory tests may reveal an increased sedimentation rate, elevated CRP, anemia and elevated creatinine due to kidney impairment. An important diagnostic test is the presence of perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) with myeloperoxidase specificity (a constituent of neutrophil granules), and protein and red blood cells in the urine.

In patients with neuropathy, electromyography may reveal a sensorimotor peripheral neuropathy.

Differential diagnosis

The signs and symptoms of microscopic polyangiitis may resemble those of granulomatosis with polyangiitis (GPA) (another form of small-vessel vasculitis) but typically lacks the significant upper respiratory tract involvement (e.g., sinusitis) frequently seen in people affected by GPA.

Treatment

The treatment of MPA is dependent on the extent of the disease, rate of progression, and the degree of inflammation. The goal of treatment is to stop organ damage that occurs as a result of MPA and involves use of medications that suppress the immune system. Treatment is typically carried out in three phases: 1.Remission induction using prednisone and cyclophosphamide. This phase usually lasts between 4 and 6 months. 2.Remission maintenance using prednisone and replacing cyclophosphamide with other medications such as methotrexate and azathioprine. This phases usually lasts between 12 and 24 months. 3.Treatment of relapse utilizing medications from phase one or other therapies such as intravenous immunoglobulin for resistant cases. The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Rituximab (Brand name: Rituxan)For the use of Rituxan (rituximab) in combination with glucocorticoids for the treatment of pateints with Wegener's Granulomatosis (WG) and Microscopic Polyangiitis (MPA).

Prognosis

The prognosis for MPA depends on the severity of the condition. Early diagnosis and prompt treatment lead to a better overall prognosis. With treatment, 75 percent of individuals achieve complete remission. After achieving remission, it is possible for MPA to recur (often referred to as a “relapse”). Relapses occur in about 30-50% of people with MPA. Achieving remission is again possible for most people with MPA.

NIH genetic and rare disease info

• NIH info on Microscopic polyangiitis

Microscopic polyangiitis is a rare disease.

Microscopic polyangiitis Resources
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