Renal Calcifications



Renal Calcifications


Eva Ilse Rubio, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Miscellaneous Hypercalcemia/Hypercalciuria


  • Chronic Diuretic Therapy


  • Renal Tubular Acidosis


  • Medullary Sponge Kidney


  • Tamm-Horsfall Proteins (Mimic)


Less Common



  • Chronic Glomerulonephritis


  • Papillary Necrosis


  • Infection/Infarction/Trauma


  • Oxalosis/Hyperoxaluria


  • Alport Syndrome


Rare but Important



  • Salt-Wasting Nephropathies



    • Bartter, Gitelman Syndromes


  • Malignancies



    • Wilms Tumor


    • Sarcoma


    • Renal Cell Carcinoma


  • Poisoning/Toxicity


  • Tuberculosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Distribution



    • Medullary nephrocalcinosis



      • Abnormal calcium deposition within renal medullary pyramids


      • Within interstitium or distal tubules


      • Represents between 85-95% of all cases of nephrocalcinosis


    • Cortical nephrocalcinosis



      • Abnormal calcium deposition within renal cortex


      • Represents minority of cases of nephrocalcinosis


  • Basic definitions



    • Nephrocalcinosis: Abnormal calcium deposition within renal parenchyma


    • Nephrolithiasis: Formation/presence of calculi within upper renal collecting system (renal calyces or renal pelvis)



      • Often calcium compounds but not exclusively


      • Calculi may or may not obstruct


    • Urolithiasis: Presence of calculi in mid to lower urinary tract (ureters, urinary bladder); obstructing or nonobstructing


Helpful Clues for Common Diagnoses



  • Miscellaneous Hypercalcemia/Hypercalciuria



    • Distribution: Medullary region


    • Numerous etiologies: Dietary, pharmaceutical, immobilization, metabolic, steroid use, familial, idiopathic, sarcoid, endocrine abnormalities


    • US more sensitive than radiographs



      • Calcifications on US have variable appearance: Punctate, coarse, granular, round, linear; ± shadowing


  • Chronic Diuretic Therapy



    • Distribution: Medullary region


    • Results from use of loop diuretics, commonly furosemide (Lasix)



      • Associated with hypercalciuria


    • More common in premature infants; many cases will resolve several months after discontinuation


  • Renal Tubular Acidosis



    • Distribution: Medullary region



      • Most reliably identified by US


      • Calcifications may be deposited at periphery of medulla or may occupy entire medullary pyramid


      • Small or sparse calcifications may not demonstrate posterior acoustic shadowing


    • Results from proximal tubule defect in bicarbonate resorption



      • Urine: May have hypercalciuria, urolithiasis


      • Blood: May have secondary hyperparathyroidism &/or hypophosphatemia


  • Medullary Sponge Kidney



    • Distribution: Medullary region


    • Primary abnormality is cystic/patulous dilatation of distal tubules



      • Urinary stasis in tubules results in precipitation of urinary calcium crystals


      • Distribution of calcifications may be patchy/asymmetric


    • Intravenous pyelogram reveals linear opacities of accumulated contrast material within dilated distal tubules


  • Tamm-Horsfall Proteins (Mimic)



    • Common mammalian urinary proteins; often conspicuous in newborn kidney



    • Considered incidental finding; typically resolves within 2-3 weeks of birth


    • Typically noted on US



      • Evenly distributed echogenicity of renal medullary pyramids; may be confused with renal medullary calcifications


Helpful Clues for Less Common Diagnoses

Tags:
Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on Renal Calcifications

Full access? Get Clinical Tree
Get Clinical Tree app for offline access