Eosinophilic granulomatosis with polyangiitis, formerly known as Churg-Strauss syndrome, is a very rare disease that causes inflammation of the small blood vessels (vasculitis).
In Eosinophilic Granulomatosis with Polyangiitis, small blood vessels that supply tissues in the lungs, sinuses, skin, nerves and almost every other organ can become inflamed. The disease can affect almost every organ in the body.
Eosinophilic Granulomatosis with Polyangiitis belongs to a family of arthritic diseases called vasculitis. The word vasculitis means inflammation of blood vessels.
One thing that makes Eosinophilic Granulomatosis with Polyangiitis different from other types of vasculitis is that everyone who has the disease also has asthma. At the start of the disease, most patients notice a worsening of their asthma.
Eosinophilic Granulomatosis with Polyangiitis gets the first part of its name, eosinophilic, from one of the features of the disease: people with Eosinophilic Granulomatosis with Polyangiitis have an increased number of a type of white blood cell called an eosinophil.
The cause of Eosinophilic Granulomatosis with Polyangiitis isn’t known, but it is thought to be an autoimmune disease. This means that it is thought that the disease is caused by the body’s immune system attacking its own small blood vessels and causing inflammation. It’s possible that an allergic trigger is involved in some people that misfires their immune system.
Who Gets Eosinophilic Granulomatosis with Polyangiitis
Eosinophilic Granulomatosis with Polyangiitis can affect anyone, but is more common in younger and middle-aged people. It affects men and women equally. It tends to occur in people who are susceptible to allergies, allergic rhinitis (hay fever) or asthma.
Understanding Eosinophilic Granulomatosis with Polyangiitis
Most people who get Eosinophilic Granulomatosis with Polyangiitis have suffered from asthma for many years. In the early stages of the disease, their asthma usually gets worse, and frequent sinus infections are common.
As Eosinophilic Granulomatosis with Polyangiitis progresses, the number of eosinophils (a type of white blood cell) starts to increase in the blood. These cells accumulate in various tissues and cause inflammation. Small blood vessels to affected areas become inflamed reducing blood flow to these areas. At this stage, people with the disease can start feeling unwell and might notice symptoms of fatigue, aches, low-grade fever, loss of appetite, weight loss, skin rashes or nodules, diarrhea, or swollen lymph nodes.
The disease tends to flare, which means that symptoms and their severity can come and go.
People with Eosinophilic Granulomatosis with Polyangiitis are at higher risk for blood clots.
Other symptoms vary depending on which organs are affected:
When Eosinophilic Granulomatosis with Polyangiitis involves the lungs, common symptoms include shortness of breath, cough, or chest pain. In some cases, lung involvement can be very dramatic and life threatening. In very severe cases there can be bleeding into the lung. If this happens, a person might cough up blood.
Eosinophilic Granulomatosis with Polyangiitis often affects the nerves in the lower part of the body. This can cause a sudden loss of strength (e.g. “foot drop”) but does not usually cause pain.
Signs of Eosinophilic Granulomatosis with Polyangiitis can appear on the skin in the form of little red dots called purpura. These can look like little bruises. They often appear on the lower extremities.
When Eosinophilic Granulomatosis with Polyangiitis affects the joints, joint aches are common. People can also experience swelling of the joints.
Digestive System (Stomach or Gastrointestinal Tract)
Inflammation of the stomach or gastrointestinal tract can happen but this is rare. This can cause abdominal pain and diarrhea. The kidneys can also be involved.
Inflammation of the tissue around the heart (called pericarditis) may also occur, but this is very rare.
There are two key features that help make the diagnosis of Eosinophilic Granulomatosis with Polyangiitis: a history of asthma and a high number of eosinophils in the blood. The disease can sometimes be challenging to diagnose because its symptoms may come and go.
The disease is often best diagnosed by a rheumatologist, a type of doctor that specializes in arthritis and autoimmune disease.
To diagnose the disease, physicians will take a careful and complete history and perform a thorough physical examination. Based on this information, the doctor will likely order tests like blood tests and x-rays to confirm their diagnosis, and to understand what tissues and organs might be involved in their patient’s particular case.
Common Tests to Diagnose Eosinophilic Granulomatosis with Polyangiitis
Counting eosinophils and looking for inflammation: The Complete Blood Count (CBC)includes a count of eosinophils, the type of white blood cell seen in high concentrations in people with Eosinophilic Granulomatosis with Polyangiitis.
Looking for inflammation: Eosinophilic Granulomatosis with Polyangiitis causes inflammation so these tests are expected to have abnormal results. Common tests include the Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), and C-Reactive Protein (CRP).
Looking for an immune response against white blood cells: The Anti-Neutrophil Cytoplasmic Antibody (ANCA) test look for antibodies that attack proteins associated with neutrophils (white blood cells). This test is positive in 30-40% of cases.
Looking for elevated IgE: Immunoglobulin E is usually elevated in people with Eosinophilic Granulomatosis with Polyangiitis.
Blood and urine tests for kidney involvement: Creatinine (a blood test) and urinalysis (urine tests) look for kidney involvement
Biopsy (Tissue Sample)
Biopsy in cases with skin or lung involvement: A tissue biopsy involves taking a very small sample of tissue through a needle to be analyzed in a lab. A physician might order a biopsy of skin or lung tissue in a patient where they suspect Eosinophilic Granulomatosis with Polyangiitis.
X-Rays looking for lung involvement: A chest x-ray or a CT-scan of the chest are often used to look for lung involvement.
Pulmonary Function Tests (PFTs) looking for lung involvement: A PFT is often used to document the presence of lung involvement and follow the lungs to determine if the disease is improving.
Tests for nerve involvement: Electromyography or Nerve Conduction Studies can be performed to look for nerve or muscle involvement.
Heart Test (ECG or EKG)
Test for heart involvement: An echocardiogram (ECG or EKG) is a test that looks for heart involvement
Scientists don’t know the cause of Eosinophilic Granulomatosis with Polyangiitis, but it is thought to be an autoimmune disease. For reasons that are not well understood, the body begins to attack small blood vessels and causes inflammation.
An allergic trigger may cause the number of a type of white blood cell, eosinophils, in the blood to rise, but the reason for this is not understood.
This disease tends to occur in people who are susceptible to allergies, allergic rhinitis (hay fever), or asthma.
Eosinophilic Granulomatosis with Polyangiitis should be treated as early and aggressively as possible to minimize damage to small blood vessels and important organs. It is also important for people to keep any asthma symptoms under control using standard asthma therapies.
A rheumatologist is usually one of the best medical specialists to help people with Eosinophilic Granulomatosis with Polyangiitis manage the disease. Some people will also need to see a lung specialist (respirologist), a nerve specialist (neurologist), or a kidney specialist (nephrologist) if the disease significantly impacts these tissues.
Medications for Eosinophilic Granulomatosis with Polyangiitis
Prednisone is the primary therapy for Eosinophilic Granulomatosis with Polyangiitis. This medicine is very effective at controlling inflammation caused by the disease. As symptoms improve and markers of inflammation return to normal, the dose of prednisone can be gradually tapered (lowered) and in some patients it can be discontinued. Some patients will need to remain on a low dose of prednisone, which can be safe and effective.
Azathioprine (Imuran) & Methotrexate
Patients who have been on cyclophosphamide for 6 months are usually switched to azathioprine or methotrexate as a long-term maintenance therapy. In milder cases, azathioprine may be used to induce remission (stop the immune system’s attack) instead of cyclophosphamide.