Overlap between dermatomyositis and ANCA vasculitides

Nephrotic Syndrome as an Extramuscular Manifestation of Anti-EJ Antibody-Positive Dermatomyositis: A Case Report and Review of the Literature

Renal involvement is underestimated as an extramuscular manifestation of dermatomyositis (DM). Here, we describe a 67-year-old woman with anti-glycyl-transfer ribonucleic acid synthetase (anti-EJ) antibody and anti-ribonucleoprotein antibody-positive DM complicated by systemic sclerosis, who developed nephrotic syndrome concurrently with the exacerbation of DM, as indicated by incremental serum creatine kinase levels, high-intensity lesions on muscle magnetic resonance imaging, and active interstitial pneumonitis on chest computed tomography. Renal biopsy revealed the presence of immune-deposition in the glomerulus by immunofluorescence. To our knowledge, this is the first report describing the coexistence of anti-EJ antibody-positive DM and nephrotic syndrome. More reports of similar cases are warranted to substantiate the association.

Juvenile dermatomyositis with IgA nephropathy: case-based review

Juvenile dermatomyositis (JDM) is the most common childhood idiopathic inflammatory myopathy (IIM). It is characterized by the classic skin rash in the form of Gottron papules and heliotrope rash, and symmetric proximal muscle weakness. Renal involvement in JDM is rare which includes acute kidney injury and glomerulonephritis. We report a 10-year-old boy with juvenile dermatomyositis and IgA nephropathy. Child responded dramatically to the conventional therapy with steroids and methotrexate for the primary disease, and did not require any additional treatment for his renal disease. Child's primary disease is in remission and has normal urinalysis with normal renal function at 6-month follow-up. We reviewed the literature and found 11 cases of IIMs with renal involvement. Four patients (one JDM, two polymyositis, and one dermatomyositis) had IgA nephropathy out of which three patients responded to the conventional therapy of primary disease and only one patient with polymyositis needed hiking immunosuppression targeted for renal condition. Therapy targeting the underlying disorder is usually sufficient in patients with JDM and secondary IgA nephropathy.

Microscopic polyangiitis with dermatomyositis

Dermatomyositis is a rare autoimmune disease with a heterogeneous presentation that often has multiple extramuscular manifestations, although it does not typically involve the renal function. A 62-year-old female presented with proximal muscle weakness and rashes, which are classic symptoms of dermatomyositis without creatine kinase (CK) elevation. Initial serologic evaluation revealed a positive p-ANCA, although she did not develop renal failure for several months, at which point renal biopsy findings were consistent with microscopic polyangiitis. The patient was initially treated with cyclophosphamide, maintained with rituximab, and has been in remission for more than 2 years. Dermatomyositis and microscopic polyangiitis are both uncommon diseases, but are concomitantly present in this patient. A positive p-ANCA and development of renal insufficiency should be promptly evaluated in dermatomyositis patients.