eMedicine Specialties > Nephrology > Hereditary Kidney Disorders

Medullary Sponge Kidney: Differential Diagnoses & Workup

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

Differential Diagnoses

Nephrolithiasis
Nephrolithiasis: Acute Renal Colic

Other Problems to Be Considered

Autosomal recessive polycystic kidney disease
Caliceal diverticula
Pyelovenous backflow in acute ureteral obstruction
Renal tuberculosis

Workup

Laboratory Studies

  • The diagnosis of medullary sponge kidney (MSK) is usually suspected in patients presenting with renal calculi, hematuria, or multiple urinary tract infections (UTIs). Prior clinical suspicion of medullary sponge kidney is important because it helps in ordering the most relevant radiological tests.
  • Metabolic acidosis may occur secondary to renal tubular acidosis (RTA) (type 1 RTA or distal RTA) and is usually diagnosed during an acidification test as an inability to reduce the pH of urine to less than 5.3. Incomplete distal RTA is more common than frank type 1 RTA and, thus, might be missed on electrolyte testing because incomplete RTA does not show resting metabolic acidosis. However, incomplete distal RTA has been known to contribute to stone formation.6
  • A defective urinary concentrating ability is the inability to achieve maximal urine osmolality (ie, 900 mOsm/kg or greater) with water restriction. However, the defect in urinary concentrating ability is usually mild, and patients are asymptomatic.
  • Hypercalciuria may occur in 30-50% of cases.
  • A higher incidence of hypocitraturia occurs in medullary sponge kidney.
  • Patients with medullary sponge kidney nephrolithiasis who are hypercalciuric have a higher incidence of renal leak–type hypercalciuria than do patients with hypercalciuric calcium stones without medullary sponge kidney.

Imaging Studies

  • The diagnosis is usually confirmed by findings on excretory urography (see Table 2).
    • Excretory urography reveals radial linear striations in the papillae.5 These are often referred to as "brushlike" patterns of the affected papillae. Cystic collections of contrast media in the ectatic collecting duct are referred to as "bunches of grapes" or "bouquets of flowers."
    • High-quality excretory urography with renal tomograms obtained before and after injection of contrast medium and then every 4 minutes during the next 20 minutes has been described as the most accurate method of identifying medullary sponge kidney. The diagnosis of medullary sponge kidney could be missed if the preparation is suboptimal.
  • Abdominal plain film may reveal nephrocalcinosis.
  • CT scan can reveal papillary calcification or hyperdense papillae but usually is not as sensitive as excretory urography (see Media files 1-2). CT scan can also be used to help identify other renal abnormalities, such as associated cysts, horseshoe kidney, renal abscess, and papillary necrosis. Helical CT scan has been demonstrated to improve the definition of the abnormalities in medullary sponge kidney.7
  • Ultrasound of the kidney in medullary sponge kidney may reveal calcification in the medullary region. In earlier cases of medullary sponge kidney without calcification, the papillae may appear bright on ultrasound.

Table 2. Radiological Appearance in Medullary Sponge Kidney



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Table
Radiologic TestAppearance
Plain radiographNormal or enlarged kidney
Medullary nephrocalcinosis indicated by isolated, single or multiple precaliceal concretions or clusters of grapelike calcifications
Excretory urogram*Papillary blush
Faint pyramidal striation
Papillary streaking or brushlike appearance
Precaliceal tubular dilatation filled with contrast
Papillary blush and multiple precaliceal dilatation
Bouquet of flowers
CT scanPapillary calcification
Hyperdense papilla
Ectasia of precaliceal tubules
Radiologic TestAppearance
Plain radiographNormal or enlarged kidney
Medullary nephrocalcinosis indicated by isolated, single or multiple precaliceal concretions or clusters of grapelike calcifications
Excretory urogram*Papillary blush
Faint pyramidal striation
Papillary streaking or brushlike appearance
Precaliceal tubular dilatation filled with contrast
Papillary blush and multiple precaliceal dilatation
Bouquet of flowers
CT scanPapillary calcification
Hyperdense papilla
Ectasia of precaliceal tubules

*Findings limited to medullary pyramids

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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