Acute nephritis in fifty children: clinical and immunological studies.

The main clinical and laboratory findings in a group of 50 children with acute nephritis are described and discussed. All the group had evidence of a streptococcal aetiology. The wide spectrum of presenting complaints, the age distribution and the high incidence among Maori children are noted. The severity of the disease, as indicated by features such as hypertensive crisis, was greater than expected. Fifty per cent of our patients experienced one or more of our defined complications. Encephalopathy was seen in 12% of all patients and severe hypertension in 34%. The striking feature of the laboratory findings was the wide variation in complement changes. No constant patterns emerged which would have implicated either the "classical" or "alternate" pathway for the activation of complement in these patients. An unexpected finding was the relatively high incidence of a transient C3 nephritic factor in post-streptococcal cases. We found also that fibrin degradation products were present in high concentrations in the urine of patients with post-streptococcal nephritis, again an unexpected finding.