Introduction
Fibroblastic rheumatism, also known as non-inflammatory soft tissue rheumatism, is a type of rheumatic disorder that affects the body's soft tissues, such as tendons, ligaments, and fascia. It is characterized by the formation of fibrous tissue, or fibrosis, in these areas, leading to pain, stiffness, and restricted movement. It was identified for the first time in 1980 and has been reported in only 40 cases, with most of the cases being of adult white males. It is not related to inflammation, unlike rheumatoid arthritis or osteoarthritis. The exact cause of fibroblastic rheumatism is unknown, but it is believed to be related to an overproduction of fibrous tissue in response to injury or inflammation.
What Is the Pathogenesis of Fibroblastic Rheumatism?
The underlying cause and mechanism of fibroblastic rheumatism are not well understood. Studies have shown that it is caused by the excessive proliferation of fibroblasts rather than an increase in collagen production. These fibroblasts also have a higher growth rate in laboratory tests and produce fewer collagen and non-collagen proteins than those in healthy tissue. This differs from another condition called systemic sclerosis, in which there is an increase in collagen production in the skin.
It is unclear what causes fibroblasts' conversion to myofibroblasts, which are believed to play a role in the disorder. External and internal factors have been suggested as possible triggers, such as infection, exposure to toxins, and certain medications. Some case reports have linked the condition to infections like hepatitis C, respiratory infections, and streptococcal infections.
It has also been found in one patient with lupus and another patient with lung cancer. However, more research is needed to confirm these associations and understand the underlying mechanisms of the disorder. Some studies suggest that certain cytokines, such as transforming growth factor-beta and granulocyte macrophage-colony-stimulating factor, may play a role in developing fibroblastic rheumatism. Additionally, successful treatment with anti-tumor necrosis factor (TNF) medications suggests that TNF-alpha may be involved in the disorder.
What Are the Signs and Symptoms?
Fibroblastic rheumatism (FR) is marked by the appearance of skin nodules and joint symptoms. The skin nodules, considered essential for diagnosis, may appear before or after the joint symptoms and can range from 5 to 20 mm (millimeters) in diameter. These nodules are usually solid, pink, or flesh-colored and are most commonly found on the upper and lower extremities, particularly around the joints such as the hands, elbows, knees, ears, and neck. They tend to disappear in 6 to 24 months with or without treatment. Other skin symptoms that may be present include sclerodactyly, thickened palmar fascia, erythematous plaques or papules, and the Raynaud phenomenon. Joint involvement can occur at any stage of the disease and typically presents as sudden onset symmetric polyarthritis or polyarthralgia, usually affecting small distal joints of both upper and lower extremities. However, there have been cases of arthritis affecting large joints such as the knees, hips, shoulders, and elbows. Initially, FR usually presents as joint stiffness without any joint destruction, but as the disease progresses, affected joints become increasingly restricted and painful, with flexion contractures of the fingers. Systemic or visceral involvement is not reported.
How to Diagnose Fibroblastic Rheumatism?
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Laboratory Diagnosis: In diagnosing FR, laboratory tests typically show no abnormalities and are normal. This can help distinguish it from other types of inflammatory arthritis. Additionally, tests for various autoantibodies, such as rheumatoid factor, anti-citrullinated antibody, and antinuclear antibody, will not be positive in patients with FR, which can also help rule out other diagnoses.
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Biopsy: A biopsy of the skin nodules is the best way to diagnose FR. The biopsy will show that the skin cells are arranged in a specific pattern and that there is a decrease in elastic fibers. The biopsy usually has no inflammation, and the muscle and tendons are unaffected.
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Immunohistochemistry: A test called immunohistochemistry is done on the cells taken from the skin nodules of FR. This test shows that the cells are similar to fibroblasts and have certain proteins that suggest they are a type of myofibroblast. These cells do not have markers found in other types of cells, like histiocytes.
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Radiology: X-ray results are usually normal at the beginning of the disease, but as it progresses, erosions and loss of bone density may occur. In the early stages, X-rays of the hands and feet may appear normal, but MRI (magnetic resonance imaging) may show early signs of synovitis or tenosynovitis. X-rays may show bone and joint changes as the disease progresses, such as narrowing the joint space and erosions. In some cases, X-rays taken in the first four months of the disease may appear normal, but later X-rays may show changes in the bones.
How to Treat This Disorder?
Early diagnosis and treatment are important to prevent permanent joint damage and disability. Different drugs such as Prednisone, Colchicine, Interferon alpha, Penicillamine, MTX, Hydroxychloroquine, Acetylsalicylate, and nonsteroidal anti-inflammatory drugs have been tried with varying results. The most effective treatment found so far is low-dose oral MTX. Interferon-alfa and Infliximab have also shown some effectiveness. Physical therapy is also crucial in maintaining joint function. One report suggests that intensive physical therapy can improve symptoms without needing medication. In some cases, surgical interventions, such as synovectomy or joint replacement, may be necessary to address severe joint damage. Regular monitoring and follow-up appointments are also essential to track progress and adjust treatment as needed.
Conclusion
In conclusion, fibroblastic rheumatism is a rare disorder characterized by the formation of fibrous tissue in the body's soft tissues, leading to pain, stiffness, and restricted movement. The underlying cause and mechanism of fibroblastic rheumatism are not well understood, but it is believed to be related to an overproduction of fibrous tissue in response to injury or inflammation. The disorder is marked by the appearance of skin nodules and joint symptoms and can be diagnosed through a biopsy of the skin nodules, which will show a specific pattern of skin cells and a decrease in elastic fibers. Treatment is important to prevent permanent joint damage, and early diagnosis and treatment are crucial. However, more research is needed to confirm the associations and understand the underlying mechanisms of the disorder.
