eMedicine Specialties > Nephrology > Hereditary Kidney Disorders

Medullary Sponge Kidney: Follow-up

Author: Amit K Ghosh, MD, DM, FACP, FASN, Associate Professor, Department of Internal Medicine, General Internal Medicine Research Fellowship, Mayo Clinic College of Medicine
Coauthor(s): Karthik Ghosh, MD, Consultant, Assistant Professor Medicine, Department of Internal Medicine, Mayo Clinic College of Medicine
Contributor Information and Disclosures

Updated: Dec 15, 2008

Follow-up

Further Outpatient Care

  • Asymptomatic adults with medullary sponge kidney
    • Advise patients about the benign nature of medullary sponge kidney (MSK), and inform them about the possibility of renal calculi and urinary tract infections (UTIs) due to medullary sponge kidney.
    • Obtaining periodic urinalysis and abdominal radiographs is recommended, although guidelines for the frequency of radiological surveillance in asymptomatic adults are unclear.
  • Asymptomatic children with medullary sponge kidney: Conduct regular surveillance for Wilms tumor and other abdominal tumors.
  • Symptomatic patients with medullary sponge kidney
    • These patients must be evaluated routinely using a renal function test, radiological surveillance, and ultrasound.
    • Urinary pH of more than 5.3 in adults and more than 5.6 in children in the setting of non–anion gap metabolic acidosis can indicate the presence of distal RTA (type 1). However, urinary pH can also be alkaline in the presence of UTI because of urea splitting organisms. The diagnosis of this disorder can be established simply by raising the plasma bicarbonate concentration toward the reference range (ie, 18-20 mEq/L) with an intravenous infusion of sodium bicarbonate at a rate of 0.5-1.0 mEq/kg/h. The fractional excretion of bicarbonate is less than 3%, and the urine pH remains relatively stable in type 1 disease. Raising the plasma bicarbonate concentration to 18-20 mEq/L has little effect on bicarbonate excretion in type 1 RTA because no defect in proximal reabsorptive capacity exists.
    • The presence of urinary infection with urea splitting organisms can lead to struvite stones and subsequent renal insufficiency. This must be identified and promptly treated.
  • Patients with medullary sponge kidney and other renal or congenital abnormalities must be evaluated for oncological tumors.

Complications

  • Renal stones
  • Hematuria
  • Distal RTA (type 1 RTA)
  • Renal insufficiency (rarely)

Prognosis

  • Medullary sponge kidney is usually a benign disorder without any serious morbidity or mortality. However, renal insufficiency may occur in as many as 10% of patients with medullary sponge kidney.
  • Occasionally, patients can have recurrent nephrolithiasis, which can lead to significant morbidity.
  • If any suggestion of history of medullary sponge kidney in other family members exists, further investigations may be indicated to unravel the genetic pattern of transmission.
  • Some physicians may encounter patients with medullary sponge kidney who claim severe, chronic renal pain without any manifestation of infection, stones, or obstruction. The source of this pain is unclear. These patients may be treated best by physicians comfortable with chronic pain management.
  • A grading system has recently been devised that could identify patients with medullary sponge kidney who are at an increased risk for complications based on intravenous urographic findings.8

Patient Education

  • Patients should receive educational materials, including handouts, informing them about the importance of maintaining volume expansion to maintain a urine output in excess of 2 liters per day. Handouts should indicate that medullary sponge kidney is a benign disorder and requires no specific therapy.
  • Patients with medullary sponge kidney can have recurrent stone disease and UTI that occasionally result in gross hematuria.
  • Patients with medullary sponge kidney should be informed of the possibility of a genetic role in their condition if other members of their families have a history of renal stones.
  • Young children with medullary sponge kidney may need regular follow-up and evaluation because incidence of Wilms tumor and other abdominal tumors is increased in this group.
  • For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center. Also, see eMedicine's patient education article Blood in the Urine.

Miscellaneous

Medicolegal Pitfalls

  • Confusing medullary sponge kidney for other diagnoses mentioned under Differentials leads to needless investigation.
  • Failure to properly treat calculi may lead to renal impairment.
  • Failure to clear urinary infection may lead to renal impairment. Hypercalciuria in patients with medullary sponge kidney could occur due to impaired calcium reabsorption in the damaged collecting tubules.
  • Adults with medullary sponge kidney presenting with gross hematuria should be investigated properly for additional causes of hematuria, such as bladder tumors.

Special Concerns

  • Children with medullary sponge kidney identified in childhood must be evaluated for other urological abnormalities and must undergo surveillance for future urological and abdominal tumors.
 


More on Medullary Sponge Kidney

Overview: Medullary Sponge Kidney
Differential Diagnoses & Workup: Medullary Sponge Kidney
Treatment & Medication: Medullary Sponge Kidney
Follow-up: Medullary Sponge Kidney
Multimedia: Medullary Sponge Kidney
References
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References

  1. Fick GM, Gabow PA. Hereditary and acquired cystic disease of the kidney. Kidney Int. Oct 1994;46(4):951-64. [Medline].

  2. Gambaro G, Feltrin GP, Lupo A, et al. Medullary sponge kidney (Lenarduzzi-Cacchi-Ricci disease): a Padua Medical School discovery in the 1930s. Kidney Int. Feb 2006;69(4):663-70. [Medline].

  3. Yagisawa T, Kobayashi C, Hayashi T, et al. Contributory metabolic factors in the development of nephrolithiasis in patients with medullary sponge kidney. Am J Kidney Dis. Jun 2001;37(6):1140-3. [Medline].

  4. Levine E, Hartman DS, Meilstrup JW, et al. Current concepts and controversies in imaging of renal cystic diseases. Urol Clin North Am. Aug 1997;24(3):523-43. [Medline].

  5. Palubinskas AJ. Renal pyramid structure opacification in excretory urography and its relation to medullary sponge kidney. Radiology. Dec 1963;81:963-70. [Medline].

  6. Higashihara E, Nutahara K, Tago K, et al. Medullary sponge kidney and renal acidification defect. Kidney Int. Feb 1984;25(2):453-9. [Medline].

  7. Lang EK, Macchia RJ, Thomas R, et al. Improved detection of renal pathologic features on multiphasic helical CT compared with IVU in patients presenting with microscopic hematuria. Urology. Mar 2003;61(3):528-32. [Medline].

  8. Forster JA, Taylor J, Browning AJ, et al. A review of the natural progression of medullary sponge kidney and a novel grading system based on intravenous urography findings. Urol Int. 2007;78(3):264-9. [Medline].

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Further Reading

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Keywords

medullary sponge kidney, sponge kidney, MSK, cystic dilatation of renal pyramids, cystic disease of renal pyramids, cystic dilatation of renal collecting tubules, congenital cystic dilatation of renal collecting tubules, precalyceal canalicular ectasia, tubular ectasia, renal tubular ectasia, renal tubules, Cacchi-Ricci disease, Lenarduzzi-Cacchi-Ricci disease, collecting tubules, medullary pyramids, kidney disease, renal disease, urinary tract infection, UTI, renal stone disease

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Contributor Information and Disclosures

Author

Amit K Ghosh, MD, DM, FACP, FASN, Associate Professor, Department of Internal Medicine, General Internal Medicine Research Fellowship, Mayo Clinic College of Medicine
Amit K Ghosh, MD, DM, FACP, FASN is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine, American Society of Nephrology, Minnesota Medical Association, and Society of General Internal Medicine
Disclosure: Mayo Clinic Foundation Royalty Editor of book, author

Coauthor(s)

Karthik Ghosh, MD, Consultant, Assistant Professor Medicine, Department of Internal Medicine, Mayo Clinic College of Medicine
Karthik Ghosh, MD is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine
Disclosure: Nothing to disclose.

Medical Editor

Frank C Brosius III, MD, Nephrology Program Director, Department of Internal Medicine, Division of Nephrology, Professor of Internal Medicine and Physiology, University of Michigan School of Medicine
Frank C Brosius III, MD is a member of the following medical societies: Alpha Omega Alpha, American Diabetes Association, American Society of Nephrology, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Eleanor Lederer, MD, Consulting Staff, Louisville VA Hospital; Professor of Medicine, Director of Nephrology Training Program, Kidney Disease Program, University of Louisville School of Medicine; Director, Metabolic Stone Clinic
Eleanor Lederer, MD is a member of the following medical societies: American Association for the Advancement of Science, American Federation for Medical Research, American Society for Biochemistry and Molecular Biology, American Society for Bone and Mineral Research, American Society of Nephrology, American Society of Transplantation, International Society of Nephrology, Kentucky Medical Association, National Kidney Foundation, and Phi Beta Kappa
Disclosure: Nothing to disclose.

CME Editor

Rebecca J Schmidt, DO, FACP, FASN, Professor of Medicine, Section Chief, Department of Medicine, Section of Nephrology, West Virginia University School of Medicine
Rebecca J Schmidt, DO, FACP, FASN is a member of the following medical societies: American College of Osteopathic Internists, American College of Physicians, American Medical Association, American Society of Nephrology, International Society of Nephrology, National Kidney Foundation, Renal Physicians Association, and West Virginia State Medical Association
Disclosure: Abbott Grant/research funds Speaking and teaching; Genzyme Honoraria Consulting; Roche Honoraria Consulting

Chief Editor

Vecihi Batuman, MD, FACP, FASN, Professor of Medicine, Section of Nephrology-Hypertension, Tulane University School of Medicine; Chief, Medicine Service, Southeast Louisiana Veterans Health Care System
Vecihi Batuman, MD, FACP, FASN is a member of the following medical societies: American College of Physicians, American Society of Hypertension, American Society of Nephrology, and International Society of Nephrology
Disclosure: Nothing to disclose.

 
 
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