Mixed connective tissue disease associated with acute polyradiculoneuropathy

[Peripheral neuropathies during systemic diseases: Part I (connective tissue diseases and granulomatosis)]

Systemic diseases (connective disease, granulomatosis) may be associated with peripheral neuropathies. The diagnosis can be complex when the neuropathy is the presenting manifestation of the disease, requiring close collaboration between neurologists and internists. Conversely, when the systemic disease is already known, the main question remaining is its imputability in the neuropathy. Regardless of the situation, the positive diagnosis of neuropathy is based on a systematic and rigorous electro-clinical investigation, specifying the topography, the evolution and the mechanism of the nerve damage. Certain imaging examinations, such as nerve and/or plexus MRI, or other more invasive examinations (skin biopsy, neuromuscular biopsy) enable to specify the topography and the mechanism of the injury. The imputability of the neuropathy in the course of a known systemic disease is based mainly on its electro-clinical pattern, on which the alternatives diagnoses depend. In the case of an inaugural neuropathy, a set of arguments orients the diagnosis, including the underlying terrain (young subject), possible associated systemic manifestations (inflammatory arthralgias, polyadenopathy), results of first-line laboratory tests (lymphopenia, hyper-gammaglobulinemia, hypocomplementemia), autoantibodies (antinuclear, anti-native DNA, anti-SSA/B) and sometimes invasive examinations (neuromuscular biopsy).

Prevalence and characteristics of immunomediated neuropathies in a group of patients with autoimmune diseases

OBJECTIVE

To determine the prevalence and the clinical-neurophysiological characteristics of immunomediated peripheral neuropathies (PN) in a group of patients with systemic autoimmune diseases.

METHOD

Fifty-nine patients with proved systemic autoimmune diseases were included. Patients underwent clinical examination and nerve conduction studies to diagnose the PN.

RESULTS

Immune PNs were detected in 18 patients (30.5%). Out of the total number of PNs (18), 39% were sensory-motor polyneuropathies, 33% mononeuritis multiplex, 11% pure sensory polyneuropathies, 11% cranial neuropathies, and 6% proximal motor neuropathies, such as the Guillain-Barré syndrome. Nine PNs (50%) appeared at the onset of the connective tissue disorders, and the rest of the cases appeared during the course of the disease. Of the total of PNs detected in this study, only 45% had a previous diagnosis. Vasculitis was the disease that presented more associated PNs. Systemic lupus erythematosus showed the widest range of PN clinical varieties.

CONCLUSIONS

The first national prevalence rate of PNs in patients with systemic autoimmune diseases was provided: 30.5%. No comparative data were found in the international bibliography. Sensory-motor polyneuropathy was the most frequently observed form of PN, followed by mononeuritis multiplex. The NPs appeared with the same frequency both at the onset and during the course of the diseases under study; these predominated at the onset of vasculitis and primary Sjögren syndrome. The compromise of the peripheral nervous system is underdiagnosed.

Treatment of mixed connective tissue disease

Mixed connective tissue disease (MCTD) is believed to be incurable and seems to have a variable prognosis. Some patients have a mild self-limited disease, whereas others develop major organ involvement that requires aggressive treatment. Because no controlled clinical trials have been performed to guide therapy in MCTD, treatment strategies must rely largely upon the conventional therapies that are used for similar problems in other rheumatic conditions (systemic lupus erythematosus, scleroderma, polymyositis). Given the heterogeneous clinical course of MCTD, therapy should be individualized to address the specific organ involved and the severity of underlying disease activity. Corticosteroids, antimalarials, methotrexate, cytotoxics (most often cyclophosphamide), and vasodilators have been used in the treatment of MCTD with varying degrees of success.