Download Neonatal Hydronephrosis

Antenatal Hydronephrosis
Definition: APD  4 mm (or 5 mm)
Incidence: 1:188
Approximately 50% of antenatal scans are
normal postnatally
Posterior urethral valves account for 1.4%,
and are the only definite indication for
surgery.
Possibility of Abnormality
If APD  20 mm, 94% had a significant
abnormality requiring surgery or long-term
follow-up.
If APD was 10-15 mm, 50% had an
abnormality.
If APD was  10 mm, only 3% had an
abnormality.
Postnatal Investigations
Renal echo: performed at 1 and 6 weeks
– US at 1 week can be omitted in mild HN (< 10
mm APD)
VCUG: all patients with persistent HN on
postnatal ultrasound
Dynamic renography: diuretic renograms
– Persistent HN in the absence of VUR, or APD
> 10 mm even in the presence of VUR
Whitaker Test
Measure the pressure gradient between
the pelvis & bladder under fixed infusion
rate.
– Less than 15 mmHg: normal
– Above 20 mmHg: favor obstruction
UPJ Obstruction
Approximately 1 in 2000 children
Male : female ratio of 3 : 1
Bilateral: 20-25%
Cause: intrinsic (75%), high insertion of
the ureter, peripelvic fibrosis, or vessels
Diagnosis: generally suspected with HN
without hydroureter, and a normal bladder
and normal amniotic fluid volume
Treatment
Influenced by renal function, infection
Surgical correction: dismembered
pyeloplasty
Indication for surgery
– Bilateral UPJO
– Unilateral UPJO with Gr. 4 HN, reduced renal
function (< 40%), or deterioration (decrease
by > 10%)
Most patients do well with no long-term
sequelae