Medication Summary
Thiazide therapy, in addition to restriction of animal protein intake, and aggressive diuresis may be helpful in patients with medullary sponge kidney and hypercalciuria.
Patients with medullary sponge kidney who demonstrate risk factors for stone formation (ie, hypocitraturia, hypercalciuria, hyperuricosuria, hyperoxaluria) should be considered for treatment with potassium citrate to prevent stone formation. [10]
Diuretics
Class Summary
The primary role of thiazide diuretics is to decrease hypercalciuria.
Hydrochlorothiazide (Esidrix, Microzide, HydroDIURIL)
This agent inhibits the reabsorption of sodium in distal tubules, causing increased excretion of sodium and water, as well as of potassium and hydrogen ions. Its use is indicated in patients with medullary sponge kidney with hypercalciuria.
Urinary Alkalinizing Agents
Class Summary
Patients with medullary sponge kidney who demonstrate risk factors for stone formation (ie, hypocitraturia, hypercalciuria, hyperuricosuria, hyperoxaluria) should be considered for treatment with potassium citrate to prevent stone formation.
Potassium citrate (Urocit K)
Potassium citrate is a potassium-based alkalinizer. The starting dose of potassium citrate is 20 mEq/day and should be adjusted to keep a urinary citrate level of 450 mg/day and a urinary pH level of less than 7.5.
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IVU-like, volume-rendered (VR) computed tomography (CT) scan of both kidneys demonstrates brushlike densities throughout multiple papillae of both kidneys consistent with renal tubular ectasia. Correlation of the stone disease with the ectatic tubules is diagnostic of medullary sponge kidney. Image courtesy of Dr. Terri J. Vrtiska, Consultant, Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
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Unenhanced coronal, volume-rendered (VR) computed tomography (CT) scan of the kidneys demonstrates 2 small calculi in the midportion of the right kidney and 2 small calculi in the lower pole of the left kidney (arrowheads). A large, low-density lesion in the lower pole of the right kidney and a small, low-density lesion in the upper pole of the left kidney (short arrows) were shown to represent benign simple renal cysts on the contrast-enhanced CT scans. Image courtesy of Dr. Terri J. Vrtiska, Consultant, Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
Tables
Frequency |
Clinical Findings |
Etiology |
Common* |
Nephrolithiasis (calcium oxalate, calcium apatite) |
Hypercalciuria Increased oxalate concentration Tubular acidification defects Hypocitraturia |
Hematuria (gross 10-20%, microscopic) |
Acute pelvic obstruction UTI, renal stones, or absence of both |
|
UTI |
Sterile pyuria common even in absence of stones Presence of renal stones |
|
Rare |
Chronic kidney disease |
Repeated urinary obstruction Repeated pyelonephritis due to urease-producing organisms (Proteus) |
*Asymptomatic |
||
Radiologic Test |
Appearance |
Plain radiograph |
Normal 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 scan |
Papillary calcification Hyperdense papilla Ectasia of precaliceal tubules |
*Findings limited to medullary pyramids |
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