Abstract
Introduction: Juvenile dermatomyositis (JDM) and juvenile polymyositis (JPM), both idiopathic inflammatory myopathies (IIM), are rare diseases with a potentially severe prognosis. Diagnosis and care for patients suffering from IIMs is concentrated in specialized centres.
Aim: To retrospectively analyze a cohort of paediatric patients with JDM and JPM followed in two paediatric rheumatology centres in the Czech and Slovak Republics. Methods: Patients with JDM and JPM followed at the Centre for paediatric rheumatology and autoinflammatory diseases of the Department of Paediatrics and Adolescent Medicine, General University Hospital in Prague in the years 2005-2013 and at the Rhematology Clinic of the Department of Paediatrics, Comenius University Medical School and National Institute of Children's Diseases in Bratislava in the years 2014-2018 were included.
Demographic and clinical data were extracted from electronic and paper medical records. During routine follow-up visits, health and functional status were assessed using validated tools (MMT8, CMAS, VAS, CHAQ).
Acquired data were analyzed retrospectively. Results: Altogether, 25 children with IIM were included.
At the Czech centre, we identified 17 patients (12 female, 5 male) with IIM (15 JDM, 2 JPM), of whom 14 were still being followed-up at the time of inclusion. Eight pacients from the Slovak centre were included (all female, 7 JDM, 1 JPM), all of whom were followed up at the time of inclusion.
In Czech patients, the diagnosis of IIM was established at the median age 7.7 (range 1.2-15.8) years, the Slovak patients were slightly younger (6.8; 1.1-15.0 years) at diagnosis. In the entire cohort, muscle (95%) and skin (88%, 100% for JDM) disease were most frequent, followed by constitutional (68%) and joint manifestations (28%).
The concentration of at least one muscle enzyme (AST, ALT, LD or CPK) was elevated in 72% of patients, in up to 24% the elevation was only mild (up to 2-3 times the upper limit of normal). Magnetic resonance imaging of muscles (sensitivity 80%) and nailfold capillaroscopy (sensitivity 87%) proved to be useful diagnostic tools in our cohort.
All patients (100%) were treated with glucocorticoids and the majority (96%) also with methotrexate with good results: muscle strength, as measured by standardized tests, improved significantly, quality of life was good and permanent damage was mild. However, long-term complications developed in a significant number of patients: lipoatrophy (n=8), contractures (n=8), calcinosis (n=10) and growth retardation (n=6).
During follow-up (median time of follow up 3.3, range 0.2-12 years) there was no patient with a fatal outcome. Among Slovak patients, some cases with significant diagnostic delay were noted (median 0.5; range 0.1-9.0 vs. median 0.3; range 0.1-1.5 years in Czech patients).
Conclusion: Demographic characteristics, clinical manifestation, treatment and outcomes in Czech and Slovak children with JDM and JPM were comparable to published cohorts. Despite adequate treatment, complications were frequent.
Diagnostic delay in some cases may have contributed to their development.