Maps for diagnosis and management of antenatal urinary tract dilatation

Vesicoureteral reflux in infants with isolated antenatal hydronephrosis

Standardized evaluation of all newborns with antenatally recognized hydronephrosis (ANH) at The Hospital for Sick Children (HSC) has included voiding cystourethrography (VCUG). This paper reviews this protocol to determine: (1) the prevalence of vesicoureteral reflux (VUR) in isolated ANH and (2) the value of performing VCUG in cases of mild hydronephrosis, defined as renal pelvis dilatation <10 mm on postnatal ultrasonography (US). A retrospective chart review was performed on infants referred with ANH. The inclusion criterion was isolated ANH. Exclusion criteria were (1) presence of additional genitourinary abnormalities and (2) no VCUG. Pelviectasis was categorized according to the anteroposterior diameter of the renal pelvis. There were 111 infants with isolated ANH. All except 3 underwent VCUG. There were 68 children (63%) with normal postnatal US or mild pelviectasis (<10 mm). VUR was detected in 16 patients, of whom 10 had mild or absent pelvic dilatation. There was no correlation between the degree of pelviectasis on postnatal US and the presence or severity of VUR ( P=0.567 and P=0.802). VUR was detected in 15% of children with isolated ANH, many of whom had normal postnatal US or mild postnatal pelviectasis. VCUG is the only reliable test for detecting postnatal VUR.

[Urinary tract abnormalities with prenatal diagnosis: neonatal management and outcome of 100 children born 1988-1990 at the Angers CHU (University Hospital)]

Malformative uropathies diagnosed in utero are increasing in number. This work describes the decision strategy adopted in Angers concerning the neonatal handling of those abnormalities.

PATIENTS AND METHODS

One hundred children born between 1988 and 1990, with prenatally suspected fetal uropathy, were included in the study and followed for a period of 3 years. In every case, an ultrasound scan was performed at birth. In cases with persistent abnormality, a voiding cystourethrography was done in the first week of life. An intravenous urograph and/or a nuclear renography were performed during the second month of life.

RESULTS

Twenty-nine children were normal. Seventy-one were affected by 126 isolated or related uropathies; the most frequent ones were the ureteropelvic junction obstruction syndrome (48), ureterovesical junction obstruction (18) and multicystic kidneys (13). A vesicoureteral reflux was associated in 22% of cases. The diagnosis was perfectly correlated with the prenatal diagnosis in 50% of cases. Fourteen of the normal children had a later ultrasound scan control, between 2 and 9 months; later on, three of them showed a moderate ureteropelvic junction obstruction syndrome. Amongst the 48 ureteropelvic junction obstruction syndromes, 22% have been operated on. The others obstructive uropathies remained stable or spontaneously improved.

DISCUSSION

These results require us to discuss as matter of priority the large number of spontaneously regressive prenatal hydronephrosis and the necessity to establish a consensus for the pre and postnatal pathological thresholds of the anteroposterior pelvic diameter, the interest in carrying out a voiding cystography after the birth when dilatation is confirmed, the interest of nuclear renography for the diagnosis and follow-up of obstructive uropathies and the absence of urgency for surgery.

CONCLUSION

We propose a decision tree specifying the action to take when facing the diagnosis of a prenatal hydronephrosis. It could be a part of the reflection for the medical teams handling these uropathies is the aim of a consensual attitude which is now essential.

Correlative imaging of the kidney

The proliferation of imaging methods for the kidney and urinary tract, combined with advances in technology and the introduction of new techniques, has created uncertainty in selecting the most efficient method for evaluating many problems encountered in clinical medicine. The main advantage of nuclear medicine lies in demonstrating the pathophysiology involved. Recent developments in Doppler ultrasound and magnetic resonance imaging with different pulse sequences and paramagnetic contrast agents also have shown promise for imaging physiological processes. However, there is little literature to support their advantage over nuclear medicine procedures in many common clinical situations. The complementary nature of nuclear medicine studies in the imaging evaluation of hydronephrosis, renal artery stenosis, flank pain, renal mass, pyelonephritis, and the transplant kidney is reviewed.

Follow-up evaluation of anomalies of the vesicoureteric junction

Anomalies of the vesicoureteric junction are important, particularly obstruction and reflux, as they may predispose to urinary tract infection. Over a 5-year period, 52 babies were referred with dilatation of the urinary tract detected antenatally or/and postnatally by ultrasound. Sixteen had an anomaly of the vesicoureteric junction: 9 had vesicoureteric reflux, 3 had ureteroceles, 1 had urethral stenosis with secondary reflux and 3 had stenosis of the vesicoureteric junction. Ten patients underwent 14 surgical procedures. The mean time to reconstructive surgery was 9.3 months. Ultrasonography showed regression of the dilatation in all patients who underwent surgery. Seven patients with minor dilatation are still under observation. In only 1 case was there loss of renal parenchyma. With conservative medical treatment the patients are 1 year old before reconstructive surgery is undertaken; with reflux, however, progression may indicate earlier surgery.