Multicystic dysplastic kidney (MCDK) is the most common cause of cystic disease in children. It is characterized by multiple non-communicating cysts of varying sizes with no identifiable normal renal parenchyma. The incidence ranges from 1 in 1000 to 4300 live births, and it is one of the most commonly detected anomalies on prenatal ultrasound. MCDK has been shown to follow a benign course with relatively few sequelae and therefore should be managed conservatively. Currently, the key clinical questions revolve around the detection of anomalies in the contralateral kidney and follow-up imaging. The recent literature suggests that very limited radiographic evaluation of the MCDK is needed. The use of voiding cystourethrogram or nuclear medicine renal scans should be directed by any abnormalities on renal ultrasound or the development of urinary tract infections.

Update on Multicystic Dysplastic Kidney.

The urological management of multicystic dysplastic kidneys (MCDK) in the paediatric population is controversial. Historically, MCDK was rare, presenting with a palpable mass or symptoms, and was managed with open nephrectomy. Wilms’ Tumor (WT) was listed in the differential diagnosis. Introduction of antenatal ultrasound (US) transformed unilateral MCDK into a common condition (1/4300 live births) which is generally asymptomatic at presentation. Observation through a MCDK registry determined and reported in 1993 that the low risk of WT developing in these kidneys did not justify prophylactic nephrectomy and that observation with periodic US was safe. However, as of 2007, a cost-effective protocol, had not been established. With widespread adoption of paediatric laparoscopy, there was potential for the pendulum to swing back to prophylactic nephrectomy as management for MCDK. However, the indications cited for intervention were more to relieve the iatrogenic symptoms caused by long-term observation, those being parental anxiety and costs to the health care system, rather than any confirmed medical indications.

Multicystic dysplastic kidney in the neonate: the role of the urologist.

Evidence-based treatment of multicystic dysplastic kidney: a systematic review.

A meta-analysis of the incidence and fate of contralateral vesicoureteral reflux in unilateral multicystic dysplastic kidney.

Congenital renal hypoplasia/dysplasia refers to the end result of a variety of pathogenic mechanisms that disturb the primary induction of metanephric progenitor cells (renal agenesis), dysregulation of nephron number (disorders of progenitor pool size or ureteric bud branching), aberrant progenitor cell differentiation (dysplastic tissue elements), disturbance of the renal vasculature (causing tubular dysgenesis), organ structure (multicystic/dysplastic kidney), and tissue migration (horseshoe kidney, ectopic kidney). Many of these disturbances are linked to mutation of genes in molecular cascades involved in the development of other organs; thus, renal hypoplasia/dysplasia can be seen with a variety of non-renal malformations. It has been useful to assemble large heterogeneous pediatric cohorts under the umbrella term of congenital anomalies of the kidney and urinary tract (CAKUT) as a way to study classification and identification of underlying genes without bias [1]. In this chapter we consider forms of CAKUT associated with reduced functional renal mass at birth.

http://link.springer.com/content/pdf/10.1007%2F978-3-642-27843-3_4-1.pdf

Renal Dysplasia/Hypoplasia

This study was performed to evaluate the clinical course and renal outcome of patients with unilateral multicystic dysplastic kidney (MCDK). We retrospectively reviewed the medical records of 59 cases with MCDK followed at Sanliurfa Children's Hospital between January 2009 and February 2013. The median age of the patients (boys 52.5%) was 31 months (range: 6-197) and the median follow-up period was 23 months (range: 6-111). Forty-two (71.2%) patients were diagnosed antenatally. The MCDKs were found more often on the right side (55.9%). The most frequently associated urological abnormality was contralateral vesicoureteral reflux (VUR) (26.6%). A total of 3 (5%) patients developed chronic renal insufficiency (CRI), 2 of whom had grade IV and V VUR; the other patient with CRI had a small and hyperechogenic contralateral kidney, suggesting dysplasia-hypoplasia, without any urological anomalies on imaging studies. The size of MCDK was unchanged in 20 (34%), had regressed in 26 (44%), and had increased in 9 (15.3%) patients. Total involution was documented in 4 (6.7%) patients. Compensatory hypertrophy occurred in 36/45 (80%) patients, with a mean age of 19.2±8.3 months. Proteinuria and hypertension were detected in 1 (1.7 %) patient each. In conclusion, abnormalities in the contralateral kidney in patients with MCDK increase the risk of renal failure. An initial investigation for associated urinary tract malformations should be done and the growth and function of the contralateral kidney, hypertension, and proteinuria should be monitored in all children with MCDK.

Aybar

Papers

Unilateral multicystic dysplastic kidney in children.