RENAL GROWTH-CHARACTERISTICS IN CHILDREN BORN WITH MULTICYSTIC DYSPLASTIC KIDNEYS

Objectives, To report on the growth characteristics of the affected an d contralateral kidneys in children born with multicystic dysplastic k idneys (MCDKs). Methods. Thirty-three patients were enrolled from 1970 to 1995: 23 were initially managed nonoperatively (mean follow-up 3.3 9 years), and 10 underwent nephrectomy Patients underwent: radionuclid e renal imaging and contrast voiding cystography. Serial ultrasonograp hy was used to obtain measurements of the affected and contralateral k idneys. Blood pressure measurements and serum creatinine levels were a vailable in some patients. Results. Among the 23 nonoperative patients , the affected MCDK involuted in 4 patients during a mean follow-up of 4.5 years at a rate of 1.02 cm/yr (24% annually); 7 kidneys decreased in size at a mean rate of 0.38 cm/yr (5.8% annually); 6 grew at a mea n rate of 1.16 cm/yr (9.9% annually); 1 kidney did not change in size; and 5 children were lost to follow-up. The mean size of the contralat eral kidneys at birth was 5.3 cm, 2 standard deviations larger than no rmal. Over time, this relative hypertrophy was maintained at a growth rate of 0.89 cm/yr (18.5% annually). Two patients who had undergone ne phrectomy also had serial postoperative ultrasonic renal measurements, and contralateral growth was 0.61 cm/yr (12.16% annually). AII but 1 patient had normal blood pressure measurements and serum creatinine le vels. Conclusions. Most MCDKs involute or decrease in size over time, although this may take many years. Contralateral hypertrophy is seen a t birth and is maintained during childhood growth, regardless of wheth er the affected kidney is removed. There is no associated hypertension or malignancy when the dysplastic kidney is left in place. (C) 1998, Elsevier Science Inc. All rights reserved.