A prospective search for urinary tract abnormalities in infants with isolated preauricular tags.

OBJECTIVE: To determine whether isolated preauricular tags are associated with urinary tract abnormalities. METHODOLOGY: Seventy consecutive infants with isolated preauricular tags were examined by ultrasonography for urinary tract abnormalities on day 3 or 4 of life between January 1993 and August 1999, after parental consent and ethics approval. Karyotype analysis was conducted in all infants with urinary tract abnormalities. The study group was compared with a control group of 69 infants without preauricular tags hospitalized during the same period. The control group consisted of infants who underwent urinary tract ultrasonography as part of an investigation for persistent regurgitation and/or vomiting associated with cyanotic spells. RESULTS: Urinary tract abnormalities were detected in 6 infants with isolated preauricular tags (6/70; 8.6%). Types of anomalies were as follows: hydronephrosis in 5 cases and horseshoe kidney in 1 case. The causes of hydronephrosis were ureteropelvic junction obstruction in 3 cases and vescicoureteric reflux in 2 cases. None of the infants in the control group had such abnormalities. All infants with urinary tract abnormalities had normal chromosomes. No statistically significant differences existed between groups concerning birth weight, gestational age, intrauterine growth, and male-to-female ratio. CONCLUSIONS: This study suggests a significant prevalence of urinary tract abnormalities in infants with preauricular tags. We recommend, therefore, that urinary tract ultrasonography be conducted in the routine assessment of infants with isolated preauricular tags.