Medium-size-vessel vasculitis

Medium-size-artery vasculitides do occur in childhood and manifest, in the main, as polyarteritis nodosa (PAN), cutaneous PAN and Kawasaki disease. Of these, PAN is the most serious, with high morbidity and not inconsequential mortality rates. New classification criteria for PAN have been validated that will have value in epidemiological studies and clinical trials. Renal involvement is common and recent therapeutic advances may result in improved treatment options. Cutaneous PAN is a milder disease characterised by periodic exacerbations and often associated with streptococcal infection. There is controversy as to whether this is a separate entity or part of the systemic PAN spectrum. Kawasaki disease is an acute self-limiting systemic vasculitis, the second commonest vasculitis in childhood and the commonest cause of childhood-acquired heart disease. Renal manifestations occur and include tubulointerstitial nephritis and renal failure. An infectious trigger and a genetic predisposition seem likely. Intravenous immunoglobulin (IV-Ig) and aspirin are effective therapeutically, but in resistant cases, either steroid or infliximab have a role. Greater understanding of the pathogenetic mechanisms involved in these three types of vasculitis and better long-term follow-up data will lead to improved therapy and prediction of prognosis

Role of non-polio enterovirus infection in pediatric hemolytic uremic syndrome

Verocytotoxin-producing Escherichia coli (VTEC) infections cause most cases of hemolytic uremic syndrome (HUS); 10-30% of patients, however, are negative for VTEC infection. The etiology of HUS in VTEC-negative cases remains poorly understood. Before the association between VTEC infection and HUS was recognized, sporadic cases of HUS with enterovirus infection were reported in the literature. Since May 1988, most cases of HUS in Italy have been reported to the Italian surveillance system, and in 73% of these, evidence of VTEC infection was demonstrated. The aim of this study was to determine whether the frequency of enteroviral infections was different in the acute phase of VTEC-positive and VTEC-negative HUS. Eighty-nine patients were investigated for enteroviral infection, of whom 58 were VTEC positive and 31 VTEC negative. Two serum samples from each patient were examined for seroconversion to enterovirus (coxsackie, echovirus, and picornavirus) by a complement fixation test. Serological evidence of acute infection with non-polio enterovirus was found in 33 patients (37%) [20/58 (34.5%) VTEC positive and 13/31 (41.9%) VTEC negative]. There was no statistically significant difference between the two groups. These results demonstrate that there are no significant differences for enteroviral infection in VTEC-positive and VTEC-negative patients and, therefore, enteroviral infections should not be considered a cause of HUS in VTEC-negative children