Antenatal Hydronephrosis Definition APD 4 mm or 5
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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 mm. Hg: normal – Above 20 mm. Hg: 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
