Medical expert of the article
New publications
Mixed connective tissue disease: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Mixed connective tissue disease is a rare disease characterized by simultaneous manifestations of systemic lupus erythematosus, systemic scleroderma, polymyositis or dermatomyositis and rheumatoid arthritis at very high titers of circulating antinuclear autoantibodies to ribonucleoproteins (RNP). Characteristic of the development of edema brushes, the phenomenon of Raynaud, polyarthralgia, inflammatory myopathy, hypotension of the esophagus and impaired lung function. Diagnosis is based on the analysis of the clinical picture of the disease and the detection of antibodies to RNP in the absence of antibodies, characteristic of other autoimmune diseases. Treatment is similar to that of systemic lupus erythematosus and involves the use of glucocorticoids with moderate to severe disease severity.
Mixed connective tissue disease (NWTC) occurs throughout the world, in representatives of all races. The maximum incidence falls on adolescence and the second decade of life.
[Clinical manifestations of mixed connective tissue disease
The phenomenon of Raynaud can be several years ahead of other manifestations of the disease. Often the first manifestations of a mixed connective tissue disease can resemble the onset of systemic lupus erythematosus, scleroderma, rheumatoid arthritis, polymyositis or dermatomyositis. However, regardless of the nature of the initial manifestations of the disease, the disease is prone to progression and spread with a change in the nature of clinical manifestations.
The swelling of the hands, especially the fingers, is most often noted, as a result of which they resemble sausages. Skin changes resemble those of lupus or dermatomyositis. Skin lesions similar to those of dermatomyositis, as well as ischemic necrosis and ulceration of the fingertips are less common.
Almost all patients complain of polyarthralgia, 75% have obvious signs of arthritis. Usually arthritis does not lead to anatomical changes, but erosions and deformities can occur, as in rheumatoid arthritis. Often observed weakness of the proximal muscles, both accompanied by soreness, and without it.
Kidney damage occurs in about 10% of patients and is often not expressed, but in some cases can lead to complications and death. With a mixed disease of connective tissue, sensory neuropathy of the trigeminal nerve develops more often than with other connective tissue diseases.
Diagnosis of mixed connective tissue disease
Mixed connective tissue disease should be suspected in all patients suffering from SLE, scleroderma, polymyositis or RA, with the development of additional clinical manifestations. First of all, it is necessary to conduct a study for the presence of antinuclear antibodies (ARA), antibodies to extracted nuclear antigen and RNP. If the results obtained correspond to a possible NWST (for example, a very high titer of antibodies to RNA is detected), to study the concentration of gamma globulins, complement, rheumatoid factor, antibodies to Jo-1 antigen (histidyl-tRNA -synthesis), antibodies to the ribonuclease-resistant component of the extractable nuclear antigen (Sm) and double helix DNA. The plan for further research depends on the symptoms of damage to organs and systems: myositis, renal and pulmonary disease require the implementation of appropriate diagnostic methods (in particular, MRI, electromyography, muscle biopsy).
Almost all patients have high titers (often> 1: 1000) of antinuclear antibodies detected by fluorescence. Antibodies to the extractable nuclear antigen are usually present in a very high titer (> 1: 100,000). Characterized by the presence of antibodies to the RNP, while antibodies to the Sm component of the extracted nuclear antigen are absent.
In sufficiently high titres, a rheumatoid factor can be detected. ESR is often increased.
Prognosis and treatment of mixed connective tissue disease
The 10-year survival rate corresponds to 80%, however, the prognosis depends on the severity of the symptoms. The main causes of death are pulmonary hypertension, renal failure, myocardial infarction, colon perforation, disseminated infections, cerebral hemorrhage. In some patients it is possible to maintain long-term remission without any treatment.
The initial and maintenance treatment of a mixed connective tissue disease resembles that of systemic lupus erythematosus. Most patients with moderate to severe disease respond to treatment with glucocorticoids, especially if it is started early enough. The disease of mild degree is successfully controlled by salicylates, other NSAIDs, antimalarial drugs, in some cases - low doses of glucocorticoids. Expressed lesions of organs and systems require the appointment of glucocorticoids in high doses (for example, prednisolone at a dose of 1 mg / kg once a day, orally) or immunosuppressants. With the development of systemic sclerosis, appropriate treatment is performed.