Page 5 - Multicystic dysplastic kidney (MCDK) in the neonate: The role of the urologist

Psooy

Conclusion: unknown, with the exception of bilateral CAVD,
Based on the literature, there is potential for an adult malig- which may be diagnosed on physical examination
nancy to develop in a MCDK. This risk appears to be very as a teenager. Therefore, routine US screening for
low considering the majority of persons currently over the such anomalies in boys is unlikely to provide patient
age of 35 years born with a MCDK did not have it removed. benefit, and if identified, almost certainly will result
There is no evidence to suggest that this risk is higher in in parental anxiety [Dr. Ross MacMahon, Section
MCDKs that have failed to undergo radiographic involu- of Urology, Department of Surgery, University of
tion (new) Manitoba, personal communication December 14,
Level of evidence: 4 2014]

6. Anomalies of the internal genitalia (new) Conclusions:
a. The coexistence of renal and reproductive duct Any recommendations that refer to the assessment of the
anomalies is well established. Schlegel et al found internal genitalia in patients with a congenital solitary kidney,
that 26% of men with unilateral congenital absence should be applied to patients with a history of a MCDK (new)
of the vas deferens (CAVD) and 11% of men with Level of evidence: 3
bilateral CAVD had an absent ipsilateral kidney. 40
Similarly, uterus didelphys and obstructed hemiva- Females with MCDK should have a screening pelvic US
gina have an increased association with ipsilateral following advanced puberty (new)
renal agenesis 41 Level of evidence: 4
b. More recently, the association with MCDK and anom-
alies of the internal genitalia has been identified. 42,43 Recommendations
Merrot identified ipsilateral malformation of the inter-
nal genitalia in 15% of MCDK patients, which has
12
the potential to lead to genitourinary complaints 44 The role of the urologist in MCDK
c. The known tendency for MCDKs to involute, the
low rate of prenatally diagnosed renal agenesis, and 1. Confirm the diagnosis of MCDK is correct (Grade A)
the prospective observation of children with MCDK a. US criteria are clear and make misdiagnosis of a
having anomalies of the internal genitalia that per- cystic malignancy unlikely when these criteria are
sist in spite of MCDK involution, has led to the identified by an ultrasonographer experienced in
conclusion that the congenital anomalies previously pediatrics 46
identified in those with “congenital renal agenesis” I. Those inexperienced with recognizing the
extends to those with a history of MCKD 42,43,45 US features of MCDK may misdiagnose it
d. Screening for female anomalies of the internal for severe ureteropelvic junction obstruction.
genitalia is felt to be beneficial, as the manage - This error could result in loss of renal function
ment of female anomalies of the internal genitalia that might have otherwise been salvageable
at the onset of puberty may prevent the symptoms b. In indeterminate cases, renal scan showing lack of
of acute abdominal pain and dysmenorrhoea. 43 function is supportive of a diagnosis of MCDK, but
Opportunities for diagnosis in the asymptomatic evidence of some function does not necessarily rule
female include an early pelvic US in the neonate it out. (no change). Magnetic resonance urography
47
with the assistance of vaginal infusion of saline. 43 may also provide this information 48
Alternatively, and less invasively, diagnosis may
be obtained later, with a pelvic US done upon 2. Use of clinical judgement to determine if VCUG is indicated (Grade D)
reaching the stage of advancing thelarche. [Dr. a. The decision to perform a VCUG should take into
Jenna McNaught, Department of Obstetrics & consideration the risks of the child having VUR and
Gynecology, University of Manitoba, personal developing a UTI (lowest in those with “simple”
communication, November 21, 2014 & Dr. Tarek MCDK and no history of UTI, and highest in those
Motan, Department of Obstetrics & Gynecology, with “complex” MCDK)
University of Alberta, personal communication I. The management of VUR, if diagnosed, is
December 8, 2014] beyond the scope of this guideline. However,
e. The role of screening for male anomalies of the gen- if the urologist has no intent to intervene on
ital ducts is unclear. These conditions alone, in the any identified VUR in the absence of symp-
absence of symptoms, do not require intervention. 44 toms, it would seem appropriate to defer the
Additionally, the true risk of developing infertility investigation of a VCUG until such symp-
or becoming symptomatic from such anomalies is toms occur

22 CUAJ • January-February 2016 • Volume 10, Issues 1-2