Imaging Pearls ❯ Kidney ❯ Medullary Sponge Kidney
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- Renal tubular ectasia/ Medullary sponge kidney
- “Brush”-like appearance of multiple, discrete, linear, papillary densities (2-3mm in diameter)
- Should not be confused with indistinct normal papillary “blush”.
- Renal tubular ectasia: isolated finding of linear collections
- Medullary sponge kidney: cystic collections associated with urolithiasis or medullary calcinosis
- Stone disease, hematuria
- Bilateral in 60-80% of cases
- One or more papillae may be affected.
- “ Medullary sponge kidney (MSK) is a kidney malformation that generally becomes manifest with nephrocalcinosis and recurrent renal stones; other signs may also be renal acidification and concentration defects, pre-calyceal duct ectasias (erroneously diagnosed as cysts) and neglected proximal tubular defects. MSK is generally considered a sporadic disorder.”
Medullary sponge kidney: state of the art
Antonia Fabris et al.
Nephrol Dial Transplant (2013) 28: 1111–1119 - “MSK typically involves all renal papillae bilaterally, though it may also be unilateral or affect only a few papilla, and this can be bewildering when it comes to diagnosis. The severity of the disease (symptomatic stone rate and numbers of hospital admissions and procedures required) correlates with the extent of the urographic signs.”
Medullary sponge kidney: state of the art
Antonia Fabris et al.
Nephrol Dial Transplant (2013) 28: 1111–1119 - “The initial unenhanced images allow a detection of nephrocalcinosis and small stones. The subsequent contrast-enhanced nephrographic phase gives high-resolution images of the kidneys that can detect medullary cysts. Excretory images combined with 3D reconstruction can demonstrate the characteristic findings of dilatation of the collecting tubules in MSK.”
CT urography for the diagnosis of medullary sponge kidney.
Koraishy FM, Ngo TT, Israel GM, Dahl NK.
Am J Nephrol. 2014;39(2):165-70. - Medullary Sponge Kidney is a rare disorder that affects slightly more women than men. It is thought to occur in 1 in 1,000 to 5,000 people in the United States. Although the symptoms of Medullary Sponge Kidney may begin at any age, they usually develop during adolescence or in adults between the ages of 30 and 50 years. Approximately 13 percent of all people who develop kidney stones are eventually diagnosed with Medullary Sponge Kidney. Medullary Sponge Kidney may also develop in people with Beckwith-Wiedemann Syndrome.
- The first symptoms of Medullary Sponge Kidney typically blood in the urine, stone formation or signs of a urinary infection such as excessive urination (polyuria) and/or burning and pain while urinating. In some affected individuals, calcium stones may form in the kidneys (nephrolithiasis). These stones can cause low back pain in the area of the kidneys (renal colic) and pain in the lower back and lower abdomen. A prominent feature of Medullary Sponge Kidney is the excretion of small stones with the urinary flow.