Diagnóstico diferencial das vasculites de pequenos vasos / Diferencial diagnosis of small vessels vasculitis

As vasculites representam um grupo heterogêneo de entidades clinicopatológicas, ligadas pelo achado comum de inflamação das paredes dos vasos sangüíneos. Considera-se uma vasculite como sendo de pequenos vasos (VPV) quando afeta vasos menores que artérias, isto é, arteríolas, vênulas e capilares. Entretanto, pode envolver também artérias de médio calibe. Diagnosticar uma vasculite pode ser uma condição desafiadora para o médico, que não deve medir esforços não só no sentido de reconhecer a síndrome, mas também se empenhar para realizar o diagnóstico específico e, quando possível, identificar e tratar seu fator etiológico. A VPV deve ser suspeitada em qualquer paciente com doença multissistêmica que não seja causada por infecção ou malignidade. Na maioria dos pacientes, as VPVs são benígnas e de curso autolimitado, especialmente nos casos em que a doença é restrita à pele. Contudo, os pacientes com doença agressiva necessitam de rápido reconhecimento, para que um tratamento precoce possa ser estabelecido.

Pauci-immune crescentic glomerulonephritis.

Pauci-immune crescentic glomerulonephritis (PICGN) is a rapidly progressive condition leading to renal failure within days or weeks and is potentially life threatening. Majority of these patients have clinical or pathological evidence of systemic vasculitis. PICGN may occur as renal limited disease or as a component of systemic necrotising small vessel vasculitis. Majority of these cases are attributed to Wegener's granulomatosis (WG), microscopic polyangitis (MPA) or Churg Strauss syndrome (CSS). Renal involvement is encountered in 80 to 90% cases of WG and MPA and in about 45% cases of CSS. Approximately 80 to 90% patients of untreated WG or MPA and about 60% cases of CSS are positive for anti-neutrophilic cytoplasmic antibodies (ANCA). These diseases are therefore also called as ANCA-associated vasculitis. Serial ANCA measurements provide useful information on disease activity. Renal transplant should be avoided in patients with clinical evidence of active vasculitis. Even though the treatment with oral corticosteroids and i.v. or oral cyclophosphamide results in complete long term remission in 70 to 75% patients, relapse occurs in >25% cases within a mean period of 18 months after cessation of therapy. Prognosis of untreated ANCA-associated PICGN is poor.

Glomerulonefritis crescéntica con anticuerpos anticitoplasma de neutrófilos (+) en niños: casos clínicos / Anti neutrophil cytoplasmic antibody positive crescentic glomerulonephritis in children: report of 2 cases

Anti neutrophil cytoplasmic antibodies are associated to vasculitis and crescentic glomerulonephritis in adults. However, this association has been seldom reported in children. We report two girls aged 12 and 15 years old with ANCA + glomerulonephritis. Both were subjected to a percutaneous kidney biopsy. One girl had to enter a chronic hemodialysis program. The other patient recovered her renal function and after 12 months of treatment with steroids and cyclophosphamide microscopic hematuria and proteinuria persist but with normal kidney function. ANCA should be measured in children with vasculitis and glomerulonephritis