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Hematuria is a common sign of urinary tract disease but also
occurs in otherwise healthy children.1,2 Hematuria can
present as either discolored red, brown, or tea-colored urine (eFig. 467.1), or it can present as yellow
urine with a positive dipstick for blood. Clues to the diagnosis
may be obtained from a history focused on whether the hematuria
is painless, intermittent, or persistent, or microscopic or gross.
A family history of hematuria or renal disease is important. Brown
or tea-colored urine is common in glomerulonephritis, whereas red
or obviously bloody urine suggests postglomerular bleeding. Glomerulonephritis is
commonly associated with other abnormalities of the urine such as proteinuria
and cellular casts as well as hypertension, edema, and reduced renal
function. Table 468-1 provides a simple mnemonic
for the causes of hematuria throughout the urinary tract. A diagnostic approach
and differential diagnosis for discolored urine and microscopic hematuria
are shown in Figure 468-1.
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Microscopic hematuria, defined as the presence of a positive
urine dipstick for blood and more than five RBCs/hpf on
centrifuged urine, occurs in approximately 1% of school-age
children on at least one urine sample. About 0.5% will continue
to have hematuria on two of three samples, and a third have hematuria
on three samples.1,2 Fewer than one third of patients diagnosed
with hematuria demonstrate hematuria 1 year later. Only a very small
number of children with microscopic hematuria had significant renal
or urological disease. Microscopic hematuria can occur following
vigorous exercise; thus, it is common in school-age children and
in the majority of cases is benign.
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Hypercalciuria, defined as more than 4 mg urinary calcium/kg
per day, has been found in significant numbers of children with
microscopic hematuria.3 This association is even stronger if
there is a family history of stone disease or the occurrence of
gross hematuria. The calcium-to-creatinine ratio can be used to
screen for hypercalciuria; for children or adolescents, a urinary
Ca/Cr ratio greater than 0.2 is abnormal.4
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The value of urinary tract imaging in children with microscopic
hematuria is controversial. The yield of routine IVP or ultrasound
is low, and reported findings are frequently of little clinical
significance. When microscopic hematuria persists for several months,
decisions on the need for urinary tract imaging are made based on
other concerns. Voiding cystourethrograms and cystoscopy are rarely
helpful and are not indicated for the routine evaluation of children
with either microscopic or ...