eMedicine Specialties > Radiology > Pediatrics

Multicystic Dysplastic Kidney: Follow-up

Author: John S Wiener, MD, FACS, FAAP, Clinical Assistant Professor, Division of Urology, University of North Carolina at Chapel Hill; Associate Professor of Surgery and Associate Residency Program Director, Division of Urologic Surgery, Associate Professor of Pediatrics, Duke University School of Medicine
Coauthor(s): Michaella E Maloney, Duke University School of Medicine; Ana Maria Gaca, MD, Assistant Professor, Division of Pediatric Radiology, Duke University Medical Center
Contributor Information and Disclosures

Updated: Feb 19, 2008

Intervention

The management of MCDK is a controversial topic. Routine nephrectomy is not indicated at this time. A few authors have recommended routine nephrectomy to prevent potential complications, but the rarity of such complications does not justify the surgical and anesthetic risks.

Surgery is indicated in patients with symptomatic MCDK, suspicious enlargement, hypertension, mass effect, pain, or infection. MCDK seldom requires urgent management; therefore, the asymptomatic neonate should be given several months to adjust to postnatal life before extirpation is pursued. In fragile neonates, percutaneous cyst aspiration may be used in cases where respiratory function is compromised by the size of the affected kidney. Cases in which malignancy is suspected because of a greater solid component or growth on follow-up are the exception. In addition, nephrectomy may be undertaken in combination with ureterectomy in the setting of an ipsilateral VUR.

Given the lack of definitive evidence for serious late complications, the management of asymptomatic MCDK is less straightforward. Nonoperative management requires close surveillance of the affected kidney with follow-up renal sonograms. The recommended schedule from the National Multicystic Kidney Registry calls for sonography every 3 months during the first year of life, then every 6-12 months until 5 years of age. The need for follow-up imaging after 5 years is unclear. The likelihood of malignant degeneration diminishes after the child reaches school age (>5 years).

Parents can be taught to perform abdominal examinations to screen for palpable masses. Malignant growth can be rapid. Wilms tumors have been noted to develop in between screening sonograms in other high-risk groups; therefore, it is possible that a parent could detect a large, rapid-growing Wilms tumor on casual examination between the recommended 6-month sonograms. This has not been reported in MCDK, however, and there is no reason to recommend more frequent sonograms. Finally, blood pressure should be monitored for the development of hypertension.

Ultimately, the patient’s parents will make the final decision regarding the management of MCDK. They should be fully informed of the risks of observation versus the risks of surgery. Some may opt for surgical management. Given the current lack of data, definitive recommendations for MCDK have not been established, and each instance should be managed on a case-by-case basis.

Medicolegal Pitfalls

• If MCDK is indicated on prenatal sonograms, postnatal sonography should be completed before the patient is discharged home from the hospital.
• In addition, prophylactic antibiotics are indicated until VCUG excludes VUR.
• Other factors to consider include the following:
  • The failure to diagnose and adequately treat VUR in the solitary contralateral kidney may result in renal scarring or may negatively affect the process of compensatory renal development.
  • The failure to diagnose MCDK may result from an inadequate radiologic workup or a lack of suspicion in an unusual presentation (such as respiratory function compromise or compressive effects in the GI system). It may be important to know that only a single kidney is functional.
  • The failure to adequately follow a patient with MCDK with repeated surveys for the development of malignant degeneration or hypertension, which may be life threatening.
  • Treatment of MCDK should be individualized. The financial costs of surgical versus nonsurgical management do not significantly differ, because nonsurgical management requires a minimum of 13 scans over the first 5 years of a patient's life. Long-term data regarding observation are lacking.

Special Concerns

• The clinician should always consider the likelihood of malignant degeneration and hypertension.
• The parents and the primary care provider should be fully informed about adequate surveillance for abdominal masses and the development of hypertension.
• Despite having a normal life expectancy, some children with MCDK have difficulty obtaining life insurance policies because of the diagnosis. This difficulty stems from misinformation regarding the benign natural history of unilateral MCDK among laypersons and confusion of MCDK with autosomal recessive PCKD, which can progress to renal failure.

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