ABSTRACT
Idiopathic inflammatory myopathies are a group of rare but serious diseases. The treatment of refractory idiopathic inflammatory myopathy is always challenging, especially in children. Three cases of refractory idiopathic inflammatory myopathy treated by rituximab were reported and discussed with the review of relevant literature. All were female with on-set age of 8 years and 6 months, 11 years and 7 months, 4 years and 2 months old, respectively. All had acute onset, presenting with progressive and severe muscle weakness. All lost ambulation within 1 or 2 months, with difficult swallowing and low voice. Respiratory distress occurred in case 2 after an attack of asphyxia due to an aspiration of sputum, and ventilator support was required for 1 month. Rashes were detected at the initial stage of the disease in cases 2 and 3. Patient 2 showed facial erythematous papules, spreading to her neck and hands. Patient 3 showed purplish eyelids with peri-orbital swelling, generalized edema involving all her limbs. Creatine kinase (CK) levels were markedly elevated in all the patients, ranging from 6 000 IU/L to 28 819 IU/L. Anti-SRP antibody was identified in cases 1, and anti-NXP2 antibodies were confirmed in cases 2 and 3. MRI of both thighs in all the patients showed profound muscle and fascial edema. Muscle pathology of patient 1 showed prominent fiber variation and endomysial fibrosis, with overexpression of MHC-Ⅰ. While muscle pathology in patients 2 and 3 showed scattered fiber necrosis, regeneration, endomysial edema without inflammatory cell infiltration. All the patients were diagnosed with idiopathic inflammatory myopathy and failed to the initial treatment including adequate glucocorticoids and high-dose immunoglobulin therapy. Other immunosuppressants (methotrexate, cyclophosphamide) were also tried in cases 2 and 3 with poor response. Then all the patients were treated with rituximab combined with glucocorticoids. Patient 1 regained normal strength and discontinued rituximab at the end of her last follow-up (2 years and 7 mouths). Though calcinosis developed during the follow-up period, significant improvement was noticed in cases 2 and 3 (both regained the ability to walk independently) at the end of their last follow-up after 2 years and 8 months, 3 years and 2 months respectively. Long-term rituximab therapy may improve the prognosis of refractory idiopathic inflammatory myopathy, especially with positive anti-SRP and anti-NXP2 antibodies.
Subject(s)
Child , Female , Humans , Infant , Glucocorticoids , Magnetic Resonance Imaging , Myositis/drug therapy , RituximabABSTRACT
Las Miopatías Inflamatorias Autoinmunes (MI) comprenden un grupo de enfermedades heterogéneas con presentación y características clínicas variables. Se distinguen subtipos clínicos como Polimiositis (PM), Dermatomiositis (DM), Miositis por cuerpos de Inclusión (MCI), Miopatía Necrotizante Inmunomediada (MNIM), Miositis de los Síndromes de Superposición, formas juveniles de MI (DMJ), Síndrome Antisintetasa (SAS) y Miopatía Asociada a Cáncer (MAC). La presencia de anticuerpos séricos y el infiltrado inflamatorio en la biopsia de músculo sugiere que se trata de una condición autoinmune. Realizar el diagnóstico de las MI suele ser un desafío y las herramientas diagnósticas no siempre están disponibles en la práctica diaria. Se obtuvo información sobre la disponibilidad de estos métodos del Registro Argentino de Miopatías Inflamatorias. El estudio de enzimas musculares, Anticuerpos Antinucleares (ANA), anticuerpo anti-Jo-1 y la tomografía computada de tórax, estuvieron disponibles para la mayoría de los pacientes mientras que la Resonancia Magnética de musculo (RM), el estudio de difusión de monóxido de carbono (DLco) y la biopsia muscular se realizaron en menos del 50% de los casos. La determinación de otros anticuerpos específicos de miositis, de importancia en el diagnóstico y pronóstico de la enfermedad se realizó, en mayor parte, a través de un subsidio de la SAR.
The Idiopathic Inflammatory Myopathies (IIM) comprise a heterogeneous group of acquired muscle diseases classified as polymyositis (PM), dermatomyositis (DM), Inclusion Body Myositis (IBM), Immuno Mediated Necrotizing Myopathies (IMNM), Overlap Myositis (OM), juvenile myositis, Antisynthethase Syndrome (ASS) and cancer related myositis (CAM). The presence of myositis specific antibodies in the serum and autoantibodies against target antigens and inflammatory infiltrates in muscle tissue suggests the autoimmune condition of the disease. The diagnosis of inflammatory myopathies is often a challenge and the disposal of diagnostic tools are not always available in daily practice. Information on the accessibility of these methods was obtained from the Argentine Register of Myopathies. The study of muscle enzymes, ANA, anti-Jo-1 antibodies and chest tomography were easy to get to most patients while muscle MRI, lung diffusion capacity for carbon monoxide (DLco) and muscle biopsy were performed in less than 50% of cases. Other myositis specific antibodies, necessary for disease diagnosis and prognosis, were mostly done through a subsidy from the Argentine Rheumatology Society.
Subject(s)
Muscular Diseases , Rheumatology , Diagnosis , AntibodiesABSTRACT
Las Miopatías Inflamatorias Autoinmunes (MI) comprenden un grupo de enfermedades heterogéneas con presentación y características clínicas variables. Se distinguen subtipos clínicos como Polimiositis (PM), Dermatomiositis (DM), Miositis por cuerpos de Inclusión (MCI), Miopatía Necrotizante Inmunomediada (MNIM), Miositis de los Síndromes de Superposición, formas juveniles de MI (DMJ), Síndrome Antisintetasa (SAS) y Miopatía Asociada a Cáncer (MAC).La presencia de anticuerpos séricos y el infiltrado inflamatorio en la biopsia de músculo sugiere que se trata de una condición autoinmune. Realizar el diagnóstico de las MI suele ser un desafío y las herramientas diagnósticas no siempre están disponibles en la práctica diaria. Se obtuvo información sobre la disponibilidad de estos métodos del Registro Argentino de Miopatías Inflamatorias. El estudio de enzimas musculares, Anticuerpos Antinucleares (ANA), anticuerpo anti-Jo-1 y la tomografía computada de tórax, estuvieron disponibles para la mayoría de los pacientes mientras que la Resonancia Magnética de musculo (RM), el estudio de difusión de monóxido de carbono (DLco) y la biopsia muscular se realizaron en menos del 50% de los casos. La determinación de otros anticuerpos específicos de miositis, de importancia en el diagnóstico y pronóstico de la enfermedad se realizó, en mayor parte, a través de un subsidio de la SAR.
The Idiopathic Inflammatory Myopathies (IIM) comprise a heterogeneous group of acquired muscle diseases classified as polymyositis (PM), dermatomyositis (DM), Inclusion Body Myositis(IBM), ImmunoMediated Necrotizing Myopathies, (IMNM), Overlap Myositis(OM), juvenile myositis, Antisynthethase Syndrome (ASS) and cancer related myositis(CAM).The presence of myositis specific antibodies in the serum and autoantibodies against target antigens and inflammatory infiltrates in muscle tissue suggests the autoimmune condition of the disease. The diagnosis of inflammatory myopathies is often a challenge and the disposal of diagnostic tools are not always available in daily practice. Information on the accessibility of these methods was obtained from the Argentine Register of Myopathies. The study of muscle enzymes, ANA, anti-Jo-1 antibodies and chest tomography were easy to get to most patients while muscle MRI, lung diffusion capacity for carbon monoxide (DLco%) and muscle biopsy were performed in less than 50% of cases. Other myositis specific antibodies, necessary for disease diagnosis and prognosis, were mostly done through a subsidy from the Argentine Rheumatology Society.