[Renal duplication in childhood. Incidence and clinical significance (author's transl)].

Renal duplication is the most common malformation within the urinary tract system and as such a particular challenge to the pediatrician with regard to diagnosis and therapy. It is discovered either by chance or in relation to chronically recurring urinary tract infections. Urinary tract infection is the main clinical symptom in 2/3 of all the patients with renal duplication. Incidence, age-and sex-distribution, predilection of side or bilateral occurrence, configuration of the ureter and the statistically significant combination with vesico-uretral reflux show systematic regularities and are discussed in connection with the literature. Ureterocele, concrements, obstructions or hydronephrosis often are consequences of renal duplication or, as with hydronephrosis, correlated malformations like aplasia, hypoplasia, malrotation, horseshoe kidney or duplication of the urethra. There is a causative relation between renal duplication and tumors or tuberculosis. Other correlated malformations are particularly heart malformations or myelomeningocele. It depends on the severity of the disease whether therapy will be symptomatic or operative. Between 1968 and 1974 we saw 114 children with renal duplication.