title: [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: BACKGROUND
  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.
  
  
  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: Servicio de Nefrología Pediátrica, Hospital Nuestra Señora de Candelaria, Santa Cruz de Tenerife. vgarcianieto@gmail.com
authors: V
authors: V
authors: García Nieto
authors: S
authors: S
authors: González Cerrato
authors: V E
authors: VE
authors: García Rodríguez
authors: O
authors: O
authors: Mesa Medina
authors: M J
authors: MJ
authors: Hernández González
authors: M
authors: M
authors: Monge Zamorano
authors: M I
authors: MI
authors: Luis Yanes
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine*; D000419:Albuminuria / Q000209:etiology; D001942:Breast Feeding; D003404:Creatinine / Q000652:urine*; D003430:Cross-Sectional Studies; D003894:Deamino Arginine Vasopressin; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000652:urine; D007223:Infant; D007231:Infant, Newborn; D007677:Kidney Function Tests; D008297:Male; D009994:Osmolar Concentration; D011237:Predictive Value of Tests; D011446:Prospective Studies; D058536:Pyelectasis / Q000000981:diagnostic imaging; D011859:Radiography; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016216:Ultrasonography, Prenatal; D016482:Urinalysis; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D014551:Urinary Tract / Q000002:abnormalities / Q000196:embryology; D014718:Vesico-Ureteral Reflux / Q000150:complications / Q000000981:diagnostic imaging* / Q000652:urine
chemical_list: D003404:Creatinine; D000118:Acetylglucosaminidase; D003894:Deamino Arginine Vasopressin