Sonographic long-term study: paediatric growth charts for single kidneys.
OBJECTIVE
To explore the clinical course of children with "single kidney" (defined as either a solitary or single functioning kidney) with reference to renal function (glomerular filtration rate (GFR) and proteinuria), body height and particularly sonomorphological features.


METHODS
This retrospective monocentric study evaluated 119 children with a solitary or single functioning kidney (>90% unilateral function on isotope scan) between 1997 and 2007. Patients were followed for 6.3 years (median, range 1-17) and had at least three renal ultrasound examinations (median 8). During recruitment six children were identified with chronic kidney disease (CKD) stage III or worse. These patients were analysed separately.


RESULTS
The aetiology of "single kidney" was attributed to contralateral multicystic dysplastic kidney (26%), tumournephrectomy (24%), renal agenesis (18%), hypo/dysplasia (11%) and obstructive or refluxive uropathy (18%). Irrespective of aetiology, the sonographic dimensions of "single kidneys" were in the upper range of normal paired kidneys and showed adequate growth. Compensatory renal hypertrophy (defined as >95% CI on two or more recent measurements) occurred in a third of patients. All six patients with CKD and GFR less than 60 ml/minute per 1.73 m(2) had pathological sonomorphology of their "single kidney" with inadequate renal growth (6/6), abnormal echogenicity (5/6), hypo/dysplasia (5/6). In addition, proteinuria (5/6) and short stature (3/6) were found.


CONCLUSIONS
New reference centiles were generated to assess renal size of "single kidneys" in paediatric patients. These charts will facilitate counselling of patients and parents. Further evidence for a benign clinical course of children with "single kidney" and absent additional pathology of the remnant kidney is presented.
Spira
E M
EM
Department of Paediatrics and Adolescent Medicine, University Medical Centre Freiburg, Mathildenstrasse 1, D-79106 Freiburg, Germany.
Jacobi
C
C
Frankenschmidt
A
A
Pohl
M
M
von Schnakenburg
C
C
D000293:Adolescent; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D005260:Female; D005919:Glomerular Filtration Rate; D006128:Growth; D006801:Humans; D007223:Infant; D007668:Kidney / Q000002:abnormalities* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D011507:Proteinuria / Q000000981:diagnostic imaging / Q000503:physiopathology; D012016:Reference Values; D012189:Retrospective Studies; D014463:Ultrasonography