Influence of nephrotic state on the infectious profile in childhood idiopathic nephrotic syndrome

Patients with idiopathic nephrotic syndrome present alterations in their cellular and humoral immune reactions that predispose them to the development of infectious processes.

To characterize the infectious processes in patients with idiopathic nephrotic syndrome.

Ninety-two children and adolescents with idiopathic nephrotic syndrome were assessed retrospectively. The types of infection were grouped as follows: upper respiratory tract infections; pneumonia; skin infections; peritonitis; diarrhea; urinary tract infection ; herpes virus; and others. The patients were divided into 2 groups: Group I (steroid-responsive) n = 75, with 4 subgroups-IA (single episode) n = 10, IB (infrequent relapsers) n = 5, IC (frequent relapsers) n = 14, and ID (steroid-dependent) n = 46; and Group II (steroid-resistant) n = 17. The incidence-density of infection among the patients was assessed throughout the follow-up period. Comparisons for each group and subgroup were done during the periods of negative and nephrotic proteinuria.

The analysis revealed a greater incidence-density of infections during the period of nephrotic proteinuria in all the groups and subgroups, with the exception of subgroup IA. During the period of nephrotic proteinuria, subgroups IC, ID, and Group II presented a greater incidence-density of infections as compared to subgroup IA. For the period of negative proteinuria, there was no difference in the incidence-density of infections between the groups and subgroups. Upper respiratory tract infections were the most frequent infectious processes.

The nephrotic condition, whether as part of a course of frequent relapses, steroid dependence, or steroid resistance, conferred greater susceptibility to infection among the patients with idiopathic nephrotic syndrome. The results of this study suggest that the best preventive action against infection in this disease is to control the nephrotic state.