CLINICAL DESCRIPTION
A 48-year-old White man with a history of congenital distal renal tubular acidosis and diabetes presented with low urine output for 6 months. He was diagnosed with distal renal tubular acidosis when he was 9 years old. He was not compliant to his alkali treatment. Labs were notable for a creatinine of 7 mg/dL, serum bicarbonate of 13 mEq/L with a positive urine anion gap and urine pH of 6. Plain radiographs of the abdomen and renal ultrasonograph are shown in Figs. 1 and 2, respectively.
Figure 1.
Plain radiography of the abdomen demonstrating bilateral nephrocalcinosis (transparent arrow).
Figure 2.
Renal ultrasonography in the longitudinal plane demonstrating calcification in the renal pyramids (transparent arrow) with acoustic shadowing (white arrow).
Nephrocalcinosis is a rare condition in which there is calcium deposited in the kidneys. It can be seen in a variety of congenital and acquired diseases.1 Diagnosis is often made incidentally by imaging such as plain abdominal radiography, kidney ultrasonography and abdominal computed tomography.2 In general, nephrocalcinosis is recognized as systemic disease and appropriate evaluation is needed to clarify underlying disease.2 Differential diagnosis of nephrocalcinosis includes primary hyperparathyroidism, sarcoidosis, hypervitaminosis D, medullary sponge kidney, distal renal tubular acidosis and other inherited tubulopathies. Initial laboratory evaluation including urinalysis, urine electrolyte, urine anion gap, serum calcium and phosphate, parathyroid hormone level and serum vitamin D level should be obtained based on clinical suspicion.1
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REFERENCES
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