EVALUATION
OF A CHILD WITH PROTEINURIA
Lewy,
J. E.
Department of Pediatrics,
Tulane Medical School, Tulane Hospital for Children, New Orleans,
Louisiana, USA
The presence of proteinuria on
a routine urinalysis requires evaluation as to the quantity and associated
findings. Proteinuria in
association with hypertension or diabetes is a predictor of progressive
renal failure. The
Pediatrician must be able to evaluate the child with proteinuria in order
to determine the likely diagnosis and appropriate therapy. The first step in evaluation is to
confirm the presence of proteinuria with a repeat urinalysis. If this shows 1+ or greater
proteinuria, then a quantitative measurement of protein concentration, in a
random or 24 hour urine collection, along with creatinine concentration
allows the calculation of the protein/creatinine ratio. This is normally <0.2. Protein/creatinine ratios >0.2
but <3.5 are found in a variety of states including nephritis, and
ratios >3.5 suggest the nephrotic syndrome. Workup should include careful history and physical exam,
measurement of renal function, urine culture, C3, streptococcal
enzyme, ANA, and renal ultrasound.
Transient proteinuria is usually related to renal congestion and may
be associated with exercise, or fever, or may be orthostatic. Mild to moderate proteinuria might
be related to renal structural abnormalities, urinary tract infection,
various forms of nephritis, or IGA nephropathy.
It also is seen in patients with hypertension and in
patients after some years of type I or type II diabetes. The early identification and
treatment of microalbuminuria has been shown to delay the onset of end
stage renal disease in these patients.
Marked proteinuria suggests the presence of the
nephrotic syndrome (discussed earlier in this symposium). Renal biopsies
are indicated in children with proteinuria when it is persistant and
associated with persistent hematuria, in the presence of persistent
hypocomplementemia, in the presence of atypical glomerulonephritis or atypical
nephrotic syndrome, and in staging the severity and type of treatment of
Systemic Lupus Erythematosis.