Characterization of MSM at disease onset and over time
oligoarticular, myalgia, memory loss, polyarticular, sacroiliac joints, Arthritis, fatigue, fibromyalgia, sleep disorder, tremor, arthritis, non-erosive, dizziness, oligoarthritis, headache, monoarticular, monoarthritis, arthralgia
MUSCLE ATROPHY, DISEASE COURSE, ARTHRITIS, ERYTHEMA NODOSUM, DISEASE, FIBROMYALGIA, ARTHRITIS, OLIGOARTHRITIS, SENSORY POLYNEUROPATHY, MONOARTHRITIS, SUPERFICIAL VENOUS THROMBOSIS
At disease onset, 31/37 subjects had arthritis (83.8%), 33/37 arthralgia (89.2%), and 14/37 myalgia (37.8%). Arthritis was monoarticular in 9/31 cases (29%), oligoarticular in 10/31 (32.3%), polyarticular in 5/31 (16.1%), axial in 7/31 (22.6%). Arthritis involved the sacroiliac joints in 7/31 patients (22.6%), large joints (ankle, wrist, elbow, knee) in 6/31 patients (19%), small joints of hands and feet in 1 patient (3.2%), while this information was missing in 17 cases (54.8%). Arthritis was erosive in 6/31 children (19.4%), non-erosive in 22 (71%), while the information is missing in 3 cases (9.7%). Five children out of 31 (16.1%) were positive for anti-nuclear antibodies. The HLA B27 haplotype was absent in all patients tested (18/37, 48.6%). Among the 14 subjects with myalgia, 3 had deep or superficial venous thrombosis, 3 erythema nodosum, 1 sensory polyneuropathy, 1 multiple sclerosis-like neurological manifestations, 6 symptoms suggestive of superimposed fibromyalgia (fatigue, sleep disorder, tensive headache, dizziness, memory loss, tremor) not otherwise explained.Follow-up data were available in the registry for 28/37 patients (75.7%). At the last follow-up visit (median disease duration of 21.8 years), 16 patients out of 28 had active MSM: arthralgia was present in 10/28 (35.7%), arthritis in 9/28 (32.1%), and myalgia in 7/28 (25.0%). Among the 31 cases with arthritis at disease-onset, the symptom resolved in 6 over time (19.4%) and 21 became chronic-recurrent (67.7%), while this information is missing in 4 patients. The course of arthritis was progressive in 6 cases: 2 children with monoarthritis developed oligoarthritis over time, whereas in 4 cases the axial skeleton was also involved late in the disease course. At the end of follow-up (mean age 29.0 ± 14.9 years [range 10.0 – 64.1]), 7/31 patients had erosive manifestations in the affected joints (22.6%), 1 patient had muscle atrophy, and the median total BODI was 0 (IQR 1.7, range 0–4). No predictive factors of the development of chronic erosive arthritis were identified.