What is Sarcoidosis?
Sarcoidosis (Benje-Beck-Schaumann disease, “benign lymphogranulomatosis”) is a multisystem granulomatous disease, which is most often manifested by bilateral enlargement of mediastinal nodes, the presence of lung tissue infiltrates, skin, eye symptoms, involvement of many internal organs and systems, and 25% of patients and bone-joint apparatus.
The disease occurs mainly at a young age (20-40 years), women are sick more often than men. The number of patients with sarcoidosis in recent decades has been increasing. It becomes a common chronic disease that is often difficult to differentiate from tuberculosis. According to L.V. Ozerova et al., Sarcoidosis accounts for 49% of all disseminated processes in the lungs, and 38% for tuberculosis.
Causes of Sarcoidosis
It is believed that the disease has an infectious nature, as evidenced by the high frequency of respiratory damage, the formation of granulomas similar to those observed with tuberculosis and other diseases, family (but not hereditary) cases of the disease, animal experiments in which it was possible to obtain disseminated granulomatous the process with the introduction of a homogenate from sarcoid lymph nodes and spleen. However, it was not possible to isolate the causative agent. Perhaps, in the pathogenesis of the process, immune disorders play a role. In patients, a decrease in T cell immunity is detected, which is proved, in particular, by cutaneous anergy to the introduction of a variety of antigens. In addition, they have enhanced B-cell function, as evidenced by the presence of polyclonal hyperglobulinemia, the detection in the blood serum of a high titer of antibodies to many infectious agents, circulating immune complexes, and anti-nucleoprotein antibodies.
V. I. Braude, having analyzed a large pathomorphological material, comes to the conclusion that at least 54 different diseases can produce “sarcoid” granuloma. The author believes that sarcoidosis, not being an independent disease (nosologically and etiologically), is a clinomorphological phenomenon that occurs as a result of exposure to various infectious and non-infectious agents on the basis of a special immune state, characterized in particular by a deficiency of cellular immunity.
Symptoms of Sarcoidosis
The disease begins acutely or proceeds as a chronic process. Acute cases of sarcoidosis are known as Lefgren’s syndrome, which is characterized by fever, erythema nodosum, enlarged lymph nodes of the mediastinum, as well as arthritis of mainly the knee or ankle joints. Joints swollen due to edema of periarticular tissues; fluid in their cavity is rarely detected, redness and soreness of joints during palpation is noted. In such cases, nonspecific synovitis is found in the synovial membrane, but when examining cutaneous erythematous nodes, a typical granuloma can be detected. The process is accompanied by leukopenia, eosinophilia, anemia, an increase in ESR. This is the most benign form of sarcoidosis, which most often after 1-6 months ends with a full recovery. If the process continues for more than 6 months, there is a danger of a transition to a chronic form.
Chronic sarcoidosis is manifested by asymptomatic adenopathy of the lungs or increasing pulmonary insufficiency not so much as a result of the granulomatous process in the lungs, but as a result of the development of fibrotic changes in them. There may be a generalized enlargement of the lymph nodes, damage to the liver and spleen, which often does not manifest itself clinically. Asymptomatic lesions of internal organs is considered one of the characteristic features of this disease.
In chronic sarcoidosis, the eyes (granulomatous uveitis, iridocyclitis, retinitis, etc.) and the skin can be involved in the process. Sarcoid nodules, papules of a reddish-brown color can be localized in various parts of the body, on the face, leaving subsequently deep scars.
Sometimes they are found in the area of the fingers, in the phalanges of which, when X-ray examination, rounded racemose defects (sarcoidosis of bones) are revealed. Such “dumb” cysts during a random examination can be found in various parts of the skeleton, in the skull, spine. Joint damage in chronic sarcoidosis usually occurs after months or even years from the onset of the underlying disease. These are most often episodic outbreaks of polyarthritis, which can lead to chronic joint deformation. The process is symmetrical, it affects the small joints of the hands, wrists, a laboratory study may reveal a rheumatoid factor, which indicates immunity disorders characteristic of sarcoidosis, and not a combination of the disease with rheumatoid arthritis. In some cases, the development of sarcoid monoarthritis is possible. In the synovial membrane with chronic forms of sarcoidosis, specific granulomas are detected.
Diagnosis of Sarcoidosis
The diagnosis can be made with a combination of arthritis with damage to the lungs, skin and other organs. To confirm the diagnosis, an intravital transbronchial biopsy of the lung tissue, skin nodes, lymph nodes, liver, synovial membrane, and muscles is performed. However, the patient should be spared, refraining from biopsy of lung tissue in cases where the clinical picture of the process is quite typical for sarcoidosis.
Kveim test is considered specific, which consists in the intradermal injection of 0.2 ml of a 10% suspension of sarcoid tissue (lymph nodes, spleen), prepared on an isotonic solution of sodium chloride. The result is taken into account after 4-6 weeks, when at the injection site a nodule is formed, which is a “non-squamous” granuloma. The test is positive in more than 60-75% of patients, however, its introduction into widespread practice is difficult due to the complexity of the preparation of the reagent and its standardization.
In acute cases, the process is prone to spontaneous reverse development, and sometimes salicylates may be sufficient for treatment. In protracted cases or with high activity of the process, corticosteroids are necessary, which are very effective in this disease. The dose of the drug and the duration of use depend on the location and characteristics of the process. With extrapulmonary and pulmonary manifestations, treatment begins with 40-60 mg of prednisone per day, gradually reducing the dose for 5-6 months. However, during treatment with small doses, an exacerbation of the process may occur, which requires the re-appointment of higher doses. Often, treatment is carried out for 3 years or more. The worst treatment is sarcoidosis with bone destructive changes.
With articular and skin syndromes, quinoline preparations can be prescribed. The feasibility of using immunosuppressants has not been fully studied.