2. Importance of the finding
• Most common congenital condition
discovered by antenatal US.
• ultrasonography enables us to detect the
correctable cause of hydronephrosis, such
as ureteropelvic junction obstruction.
• Failure of recognizing those needing
surgical intervention will result in
permanent loss of the kidney.
3. Fetal hydronephrosis Detection
• Grignon et al developed a grading system for hydronephrosis in
fetuses of 20 weeks gestation or greater in relation to their postnatal
findings.
• Grade I dilatations (AP renal pelvic diameter up to 1.0 cm) were
described as normal and physiologic because none of the affected
patients required surgery after birth.
• Grade II (>1.0–1.5 cm) and grade III (>1.5 cm with slight dilatation of
calices) dilatation was termed intermediate hydronephrosis; 50%
required postnatal surgical intervention.
• All patients with grade IV dilatation (>1.5-cm pelvis, moderate
dilatation of calices, no cortical atrophy) or grade V hydronephrosis
(>1.5-cm pelvis, severe caliceal dilatation, atrophic renal cortex)
required surgery.
• Their work suggests that one should be concerned with pelvic
dilatations greater than 10 mm particularly if there is associated
calyceal dilatation and loss of cortex.
4. • Clinically significant disease is more likely
if:
• (1) a grade 3 or 4 hydronephrosis is
present;
• (2) the renal pelvis diameter is > 10 mm;
• (3) the renal pelvis/kidney ratio is > 0.5.
5. Incidence:
• Pre-natal ultrasound
– detects fetal anomaly in 1% of
pregnancies, of which 20-30%
are genitourinary in origin and
50% manifest as hydronephrosis
6. Grading of Severity of
Hydronephrosis
Grade Central Renal Renal
Complex Parenchymal
Thickness
0 Intact Normal
1 Slight splitting Normal
2 Evident splitting Normal
3 Wide splitting Normal
4 Further dilatation Thin
7. Pathophysiology:
• Anatomic and functional processes
interrupts the flow of urine.
• There is a rise in ureteral pressure
causing stretching and dilation; if
pressures continue to rise, leads to
decline in renal blood flow and GFR.
• When significant obstruction is
persistent, it affects nephrogenic tissue
and results in varying degrees of cystic
dysplasia and renal impairment.
11. I-Mild (Grade II)
• These images shows mild dilatation of the pelvis as well
as the calyces of the right kidney
12. II-Moderate (III)
• The above ultrasound images show cupping of the calyces with moderate dilation
(Right kidney) of the pelvis and calyces. Despite the hydronephrosis the renal
parenchyma is still preserved.
13. III-severe (IV)
• The above sonographic images show marked dilatation of the
pelvicalyces with sever thinning of the renal parenchyma. note
almost total absence of normal renal tissue (cortex).