Nutcracker syndrome in children with proteinuria

The left renal vein entrapment (“Nutcracker syndrome“) is one of most underestimated causes of proteinuria in children. The introduction of sonographic assessment of the left renal vein to the diagnostic algorithm of proteinuria in children may simplify the finaal diagnosis.

Purpose: The sonographic assessment of left renal vein (LRV) in children with proteinuria.

Material and methods: 44 children with proteinuria aged 10 to 18 years has been studied. Group A –26 children with orthostatic proteinuria; Group B –18 children with biopsy proven glomerular proteinuria. In both groups sonographic evaluation of the LRV in supine and prone position were performed. The diameter of the LRV in the widest and aortomesenteric portion were taken. The peak velocities (PV) in these points were measured.

Results: The diameter and PV ratios were significantly different in both groups of children. In the group A the medium value of the diameter ratio was 11,4 and PV ratio was 5,65, in the group B the values were respectively 4,97 and 2,99 In the group A there was significant difference in diameter and PV ratios between supine and upright position in contrast to group B. The Park et all 2002 criteria of NCS were fulfilled in 58% in group A and in 16% in group B.

1. A high percentage of children with orthostatic proteinuria have sonographic features of the NCS.

2. The sonographic assesment of the LRV should be a part of diagnostic algorithm of proteinuria in children.