History: 22 yo female, active runner with worsening fatigue and pain.
Solution: In this case, there is medullary nephrocalcinos which has a very long differential diagnosis including:
Medullary Sponge Kidney (most common, but usually does not progress this rapidly), Renal tubular acidosis, distal (has numerous underlying etiologies, in this case it was analgesic nephropathy), hyperparathyroidism, hypercalcemia, oxalosis, papillary necrosis, and many other less common entities.
Renal tubular acidosis (RTA) is the development of metabolic acidosis because of a defect in the ability of the renal tubules to either secrete acids, or resorb filtered bicarbonate. It is characterized by a normal anion gap metabolic acidosis. The major cause of a normal anion gap acidosis in patients without renal failure is diarrhea.
There are three major subgroups of RTA with different clinical characteristics: Distal or type 1 RTA (give medullary nephrocalcinosis), proximal or type 2 RTA, hypoaldosteronism or type 4 RTA. Type 3 RTA is thought to be a combination of type 1 and type 2 and is rarely used today.
Medullary nephrocalcinosis is often asymptomatic when is it associated with MSK, but other etiologies, including RTA are often symptomatic.
Renal tubular acidosis (RTA) is the development of metabolic acidosis because of a defect in the ability of the renal tubules to either secrete acids, or resorb filtered bicarbonate. It is characterized by a normal anion gap metabolic acidosis. The major cause of a normal anion gap acidosis in patients without renal failure is diarrhea.
There are three major subgroups of RTA with different clinical characteristics: Distal or type 1 RTA (give medullary nephrocalcinosis), proximal or type 2 RTA, hypoaldosteronism or type 4 RTA. Type 3 RTA is thought to be a combination of type 1 and type 2 and is rarely used today.
Medullary nephrocalcinosis is often asymptomatic when is it associated with MSK, but other etiologies, including RTA are often symptomatic.
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