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

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ABDOMINAL ULTRASOUND
RT
L
A
B
LS LT
LS
C
D
Figure 9.5 (A) Normal neonatal kidney, showing lobulated outline, hyperechoic cortex, increased corticomedullary
differentiation and reduced renal sinus echoes. (B) Duplex kidney. The upper moiety is dilated with a thin cortex. The
lower moiety is normal. (C) Same patient as in (B). Dilated ureter (arrow) of the upper moiety of the duplex kidney
terminating in a uretercoele (arrowhead) seen in the base of the bladder at the vesicoureteric junction.
(D) Ureterocoele (arrowhead) at the base of the bladder covering the urethral orifice.
duplication predisposes to reflux, particularly into
the lower moiety and subsequently to infection.
The upper pole moiety of a duplex kidney is
more prone to obstruction either secondary to a
ureterocoele or, less commonly, with an obstructed
ectopic ureter. In the former case the obstructed
upper moiety may be associated with a dilated
ureter which can be followed to the bladder where
a ureterocoele, that is, a cystic dilatation of the distal
ureter, may be seen within the bladder at the
ipsilateral vesicoureteric junction (Fig. 9.5 B, C
and D). The ureterocoele may extend into the
urethra, causing bladder outlet obstruction which,
if severe, may result in bilateral hydronephrosis.
In the absence of any dilatation, it may be difficult
to demonstrate the duplex kidney on ultrasound.
Generally, the kidney is longer than
normal and two discrete, hyperechoic sinus
echoes can be seen. Ectopic insertion of the upper
pole ureter in a duplex system is a cause of urinary
incontinence in girls. It may not be possible to
follow an ectopic ureter to its distal end, even
when dilated, but one may be able to demonstrate
that the ureter is passing distally to the bladder.