Glomerular lesions in congenital endocardial fibroelastosis. Clinical manifestations and ultrastructural studies in two patients

Two children with congenital fibroelastosis and recurrent episodes of heart failure had overt proteinuria and hematuria; one also had a reversible nephrotic syndrome. Urinary manifestations persisted during periods of cardiac compensation. Renal biopsies revealed mesangial hyperplasia by light microscopy, identical ultrastructural lesions in the glomerular basement membrane, and deposits of fibrin in one of the biopsy specimens studied by immunofluorescence. These changes detected by electron microscopy may result in an increase in glomerular permeability independent of the renal hemodynamic disturbances associated with cardiac insufficiency. The progression of the lesions appears to be slow, although urinary manifestations may simulate an intercurrent glomerulonephritis. Pulmonary hypertension and renal venous stasis with glomerular intravascular coagulation were discussed as possible pathogenic mechanisms.