9%20ECOGRAFIA%20ABDOMINAL%20COMO%20CUANDO%20DONDE

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ABDOMINAL ULTRASOUND
POSTERIOR
E
F
Figure 9.10 cont’d (E) Small, scarred RK, due to reflux. (F) DMSA scan showing bilateral renal scarring due to reflux.
Note in particular two wedge-shaped scars in the RK.
Table 9.2 Conditions associated with urinary tract
infection (UTI)
● Vesicoureteric reflux
● Obstruction
—pelviureteric junction
—vesicoureteric junction
—posterior urethral valves
—duplex kidney with obstructed moiety/ectopic ureter
—ureterocoele
● Other structural anomalies
—duplex and/or ectopic renal anatomy
—multicystic dysplastic kidney
—prune belly syndrome
● Calculi
● Neurogenic bladder
non-dilated urinary tract. 17,18 There may be evidence
of thickening of the uroepithelium of the renal pelvis
due to intermittent renal pelvis distension. Uni- or
bilateral dilatation may be present to a mild or severe
degree and may involve the kidney and/or ureter
(Fig. 9.10). It is important to scan the renal pelves
and ureteric orifice immediately after micturition,
when intermittent dilatation due to reflux may be
demonstrated on an otherwise normal scan.
When dilatation is seen, the exact cause may be
uncertain unless reflux is actually visualized, which
is rare, and micturating cystography is required.
Although most commonly performed conventionally
by fluoroscopy using iodinated contrast
medium, radionuclide cystography and more
recently contrast sonocystography have been used
as an alternative, particularly in the older child. 18
The most common complication of reflux is infection
and most children present with at least one
episode of urinary tract infection. This can cause
renal scarring. It is important to make the diagnosis
of vesicoureteric reflux and renal scarring early in
order to prescribe prophylactic antibiotics in an
attempt to avoid the damaging complications caused
by reflux of infected urine. The ultrasound appearances
of scarring include a focal reduction in cortical
thickness, irregular outline, interruption of or loss of
the renal capsule echo or a disruption in the renal
architecture. Colour flow and power Doppler may
show triangular areas of decreased or absent blood
flow (and occasionally increased flow) and can
improve the detection rate of focal scarring on
sonography. 19 These signs can be difficult to demonstrate
in young children’s kidneys, particularly when
highly lobulated, and the most reliable method of
scar detection is a DMSA scan (Fig. 9.10F).
Chronic reflux nephropathy leads to failure of
renal growth, resulting in a shrivelled, poorly
functioning kidney. Measurements of the maximum
length of the kidneys should be routinely performed,
and can be related to age, height and weight. 12 A difference
in renal length of more than 10% between