[Should a cystography be performed on all breastfeeding infants with mild to moderate dilatation of the urinary tract? Renal function tests can help to answer this question].

Abstract

INTRODUCTION:

Pyelectasis can be defined as mild to moderate dilatation of the urinary tract and is diagnosed by means of an ultrasound scan (0.5-2cm transverse diameter in the initial ultrasound performed after birth). There is some disagreement about whether cystography should be indicated as standard practice. The aim of this study was to establish if renal function tests are useful in determining which cases of mild to moderate dilatation of the urinary tract do not require an initial cystography.

PATIENTS AND METHODS:

The study was conducted on 79 infants (57 males, 22 females) with pyelectasis. Seventy-three were diagnosed in utero and 6 after birth. All infants underwent at least one cystography and one desmopressin urine concentration test before one year of age.

RESULTS:

Compared to infants without vesicoureteral reflux (VUR) (n=68), infants with VUR (n=11; two with Grade I, three with Grade II, five with Grade III, two with Grade IV) showed a significantly lower (P=.006) maximum urine osmolality and a significantly higher microalbumin/creatinine ratio (P<.001) and NAG/creatinine ratio (P=.003). The negative predictive value of the first two tests was 93%. Sensitivity of the maximum urine osmolality to detect VUR was 72.7% (specificity 63.2%). Sensitivity of the microalbumin/creatinine ratio to detect VUR was 62.5% (specificity 75%). The positive probability ratio (PR) was 1.29 for the NAG/creatinine ratio, 2.03 for the maximum urine osmolality and 2.5 for the microalbumin/creatinine ratio. The negative PR was 0.95 for the NAG/creatinine ratio, 0.43 for the maximum urine osmolality and 0.5 for the microalbumin/creatinine ratio.

CONCLUSIONS:

Pyelectasis is a benign condition. Only 2 patients required pharmacological intervention (prophylactic treatment for VUR Grade IV patients). Initially at least, cystography should not be indicated in cases of microalbuminuria and/or normal urine concentrations.

• Authors: V García Nieto, S González Cerrato, V E García Rodríguez, O Mesa Medina, M J Hernández González, M Monge Zamorano, M I Luis Yanes
• Journal: Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia (Nefrologia) Vol. 31 Issue 2 Pg. 192-8 ( 2011) ISSN: 1989-2284 [Electronic] Spain
• Vernacular Title: ¿Debe realizarse una cistografía a todos los lactantes con dilatación leve y moderada de las vías urinarias? Las pruebas de función renal pueden ayudar a responder a esta pregunta.
• PMID: 21461013 (Publication Type: Journal Article)

Chemical References

• Creatinine
• Acetylglucosaminidase
• Deamino Arginine Vasopressin

Topics

• Acetylglucosaminidase (urine)
• Albuminuria (etiology)
• Breast Feeding
• Creatinine (urine)
• Cross-Sectional Studies
• Deamino Arginine Vasopressin
• Early Diagnosis
• Female
• Humans
• Hydronephrosis (diagnostic imaging, etiology, urine)
• Infant
• Infant, Newborn
• Kidney Function Tests
• Male
• Osmolar Concentration
• Predictive Value of Tests
• Prospective Studies
• Pyelectasis (diagnostic imaging)
• Radiography
• Sensitivity and Specificity
• Severity of Illness Index
• Ultrasonography, Prenatal
• Urinalysis
• Urinary Bladder (diagnostic imaging)
• Urinary Tract (abnormalities, embryology)
• Vesico-Ureteral Reflux (complications, diagnostic imaging, urine)