Overview.
Allergic vasculitis and granulomatosis i.e. allergic granulomatosis (AG) is also known as allergic granulomatosis or allergic granulomatous vasculitis. It is an autoimmune granulomatous vasculitis characterized by inflammation of intrapulmonary and systemic small vessels, extravascular granulomas, and hypereosinophilia, an inflammatory vasculitis characterized by asthenia, eosinophilia, and extravascular granuloma formation. The lesions mainly involve small and medium-sized arteries, but may also involve the skin, heart, gastrointestinal tract, liver, and other organs. As early as 1951 Churg and Strauss named this group of diseases as allergic vasculitis and granulomatosis. They believed that allergic factors play an important role in the development of the disease. For the first time, the disease was identified from PAN, and it was suggested that the disease could be viewed as an intermediate between PAN and Wegener’s granulomatosis, or as an intermediate between Lupus sulphur syndrome and Wegener’s granulomatosis.
Etiology
The cause of the disease is not well understood, and dust particles, avian antigens and self-antigens may be the main triggers of the disease. Animal experiments and clinical studies have demonstrated that CSS is caused by immunopathogenesis. Immune complex-mediated type III allergic reactions, IgE-mediated type I allergic reactions and sensitized T-cell-mediated type IV allergic reactions may be involved in the pathological process of the disease, and organic antigens entering the body are capable of directly activating the complement paracrine pathway.
Symptoms
This disease is a rare systemic rheumatic disease, often episodic, may be two or three months to a few years, the acute exacerbation of the patient may have fever, anemia, emaciation, general malaise and loss of appetite, sometimes fever may be arrested fever or flaccid fever, some patients with arthritis or arthralgia, but almost all patients with pulmonary symptoms as the main clinical manifestations, Churg-Strauss syndrome, the main manifestations are shown in Table 1. The main manifestations of Churg-Strauss syndrome are shown in Table 1.
1. Staging of the disease
Lanham et al. divided the development of Churg-Strauss syndrome into 3 stages:
(1) The first stage is the prodromal stage which may last for several years (usually more than 10 years, sometimes up to 30 years), and is mainly characterized by allergic rhinitis and nasal polyps, often accompanied by asthma.
(2) The second stage is characterized by eosinophilia in the peripheral blood and eosinophilic infiltration of the affected tissues, and is often manifested clinically as chronic eosinophilic pneumonia or eosinophilic gastroenteritis, and the lesions may last for several years, with remission and relapse often occurring alternately.
(3) The third stage is the systemic vasculitis stage. Clinically, not every case conforms to this staging sequence. Generally speaking, systemic vasculitis appears several years (about 3 years on average) after an asthma attack, and those who develop vasculitis soon after the onset of asthma have a poorer prognosis.
2. Respiratory manifestations
The symptoms may include allergic rhinitis, asthma, and pulmonary infiltrates.
3. Skin manifestations
About 2/3 of the patients have skin damage, which reflects the fact that allergic granuloma is mainly characterized by the involvement of small blood vessels, and is mainly manifested by various rashes, such as erythematous papular rash similar to erythema multiforme, hemorrhagic rash (petechiae or ecchymosis), and purpura of the skin in about half of the patients.
4. Neurological manifestations
Peripheral nerve involvement is predominant and often manifests as multiple mononeuritis, with an incidence of 63% to 75%. The symptoms of motor and sensory abnormalities are asymmetric and mainly seen in the lower limbs. Sensory abnormalities are more common than motor deficits in peripheral nerve involvement that occurs in the later stages of the disease.The disease less commonly involves the central nervous system, and the most common brain neuropathy is ischemic optic neuritis. The most common cerebral neuropathy is ischemic optic neuritis. Multiple mononeuritis can be gradually recovered without treatment, and can be completely recovered without sequelae after treatment.
5. Cardiac manifestations
Allergic granuloma often has cardiac involvement, which is also one of the main causes of death, and may manifest as congestive heart failure and severe cardiac insufficiency.
6. Digestive system
Gastrointestinal symptoms, including abdominal pain, diarrhea and gastrointestinal bleeding, may occur.
7. Renal manifestations
About 16% to 80% of patients have kidney involvement.
8. Joint and muscle manifestations
20% to 51% of patients have polyarthralgia and arthritis. Arthritis usually occurs in the vasculitis stage, and joints of any parts can be involved, which is manifested as wandering arthralgia. Myalgia is also very common, which is mainly located in the muscles of the calf, and is characterized by spasmodic pain, and spasmodic pain in the gastrocnemius muscle is often one of the early manifestations in the vasculitis stage of allergic granulomatosis.
Examination
1. General examination
Almost all active CSS is accompanied by varying degrees of anemia and increased sedimentation rate, may also appear blood leukopenia, anemia and leukopenia may be related to autoimmune reaction, 95% of patients with eosinophils can be more than 10%, and its absolute number averages 12.9 × 109 / L. When asthma patients are accompanied by eosinophils of more than 1.5 × 109 / L, the possibility of this disease should be considered, but should be At least 3 times repeated examination, and exclude drugs and other interfering factors.
2. Immunologic examination
75% of patients have increased serum IgE, and almost all of them have no direct relationship between the onset of the disease and HBsAg. 60% to 70% of patients have positive serum ANCA, and their P-ANCA and C-ANCA have equal clinical significance.
3. Imaging examination
Chest X-ray of CSS patients may show transient lung infiltration shadows, early in the course of the disease may show reticular changes in both middle and lower lungs, as the disease progresses, patchy or large patchy shadows may appear, sometimes the lung shadows may be wandering, mesenteric artery and renal arteriography are usually normal.
4.Histologic examination
Biopsy of any of the affected organs or tissues, such as skin, lungs and kidneys, showing angiogranulomatous changes in the affected areas with eosinophilic infiltration is valuable in the diagnosis of the disease.
Diagnosis
The diagnosis of AG is usually made on the basis of typical clinical and laboratory data. The diagnosis of the disease is generally not difficult with a history of asthma of several years’ duration with onset after middle age, or with asthma associated with allergic rhinitis and hypereosinophilia, multiple mononeuritis, pulmonary infiltrates, cardiac injury, gastrocnemius muscle pain or spasms, and the clinical picture of skin changes.
Treatment
Adrenocorticotropic hormones can be effective. Prednisone is commonly given orally. Later, according to the degree of decline in peripheral blood eosinophils to assess the efficacy of the treatment, when the symptoms improve, the condition can be gradually reduced after control of the general maintenance treatment for 1 year. Hormonal treatment is ineffective, azathioprine or cyclophosphamide can be used. After stopping the drug, most patients have no recurrence, but must be closely followed up once the recurrence, hormone therapy is not effective, should be timely application of cyclophosphamide treatment.