Small vessel vasculitis

Abstract

The pediatric small vessel vasculitides reviewed in this article are Henoch-Schönlein purpura (HSP) and the anti-neutrophil cytoplasmic antibody-associated vasculitides (AAV). The new classification criteria for HSP and Wegener's granulomatosis are now validated and will facilitate the conduct of future epidemiological studies and clinical trials. The clinical manifestations of small vessel vasculitis in children are described, and current therapies discussed. There is a lack of good clinical trial data on which to base therapy for HSP. Similarly, data based on randomized controlled trials (RCTs) for pediatric AAV are lacking, although children with AAV are for the first time now included in a RCT of mycophenolate mofetil versus cyclophosphamide. Significant challenges remain in the field of pediatric small vessel vasculitis, including the development of validated disease outcome measures and biomarkers to be used in clinical trials. Lastly, long-term outcome data are lacking in survivors of pediatric small vessel vasculitis.

Fig. 1

Pulmonary nodule in Wegener’s granulomatosis (WG). Computed axial tomography scan of thorax revealing a pulmonary nodule in a 12-year-old girl with WG with multi-systemic involvement (see also Fig. 3)

Fig. 2

Diffuse alveolar hemorrhage in WG. Chest X-ray from a 14-year-old girl with diffuse alveolar hemorrhage due to WG with high titre PR3-anti-neutrophil cytoplasmic antibody (ANCA)

Fig. 3

Crescentic nephritis in WG. Focal segmental necrotizing glomerulonephritis with fibrocellular crescent formation in a 12-year-old girl with severe WG (same patient as shown in Fig. 1)

Fig. 4

Orbital involvement in WG. a Magnetic resonance scan revealing bilateral soft tissue lesions involving the superolateral quadrants of both orbits in a 16-year-old girl with WG. b Orbital biopsy specimen from the same patient revealing perivascular granulomatous inflammation with fibrinoid necrosis of the vessel wall