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Currently filtering by tag: Crystalline nephropathy

Diagnose This (July 1, 2019)

What is your diagnosis?       ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​   ​   ​ ​...

Renal Oxalosis

A 25-year-old female presents to the hospital with malaise and a creatinine of 3.5. She reports that she was in her normal state of health until about 2 weeks ago when she had the “flu.” The patient has minimal proteinuria and bland urine sediment. A kidney biopsy was obtained. Figure 1 shows a normal glomerulus. Figure 2 shows severe chronicity. Figure 3 and 4 show polyhedral clear crystals within the tubular lumina. Figure 5 shows an increased number of oxalate crystals under polarized light. Renal oxalosis is characterized by excess deposition of calcium oxalate crystals within the kidney. There are...

Bile Stained Calcium Oxalate Crystals

A renal biopsy was performed on this 75-year-old female who presented with acute liver failure, jaundice and acute renal failure (serum creatinine 6.4 mg/dl). The predominant biopsy findings are those of acute tubular injury with scattered translucent crystals which show a fan-like morphology (Fig 1) and birefringence upon polarization (Fig 2), consistent with calcium oxalate crystals. Due to the paucity of these crystals, they are favored to represent non-specific deposition in the setting of ongoing tubular injury. Interestingly, the deposited calcium oxalate crystals are bile-stained (Fig 1), a phenomenon which may be seen in the setting of hyperbilirubinemia. Although not...

2,8 DHA Crystalline Nephropathy

The renal biopsy shown here has crystals present within the tubular lumens and cytoplasm with a brownish appearance by H&E (A) that are strongly silver positive on the Jones methenamine silver stain (B). The crystals are birefringent when viewed under polarized light (C).  These findings are characteristic of 2,8 DHA crystal deposition in the kidney resulting from a deficiency of adenine phosphoribosyltransferase. 2,8 dihydroxyadeninuria is an autosomal recessive disease resulting from pathogenic variants in the APRT gene. It is an important disease to recognize as treatment with a low purine diet and allopurinol therapy blocks formation of 2,8 DHA and...

Oxalate Due to Vitamin C

A 51-year-old female with a history of SLE was found to have acute renal failure. There was no evidence of glomerular proliferation by light microscopy but the biopsy did show (A) focal tubules with intraluminal and intracytoplasmic refractile crystals (arrows) (hematoxylin and eosin; original magnification × 100).  (B)  There are numerous intra-tubular birefringent crystals visible under polarized light (hematoxylin and eosin; original magnification × 50). These findings are consistent with kidney injury due to oxalate nephropathy. Known causes of oxalate nephropathy include primary hyperoxaluria, ethylene glycol intoxication, enteric hyperoxaluria (e.g. due to gastric bypass, chronic pancreatitis, small bowel resection, or...

Calcium Phosphate Deposits

Calcium phosphate deposits within the kidney may be seen in the setting of hypercalcemia/ hypercalciuria or hyperphosphatemia/ hyperphosphaturia. Regardless of the etiology, the result is the formation of hydroxyapatite crystals within the tubular lumens (Fig 1 and 2), tubular epithelium, tubular basement membranes or within the interstitium. The term nephrocalcinosis is usually reserved to describe the presence of tubulointerstitial calcium phosphate deposits in patients with hypercalcemic disorders. These include, among others, hyperparathyroidism, sarcoidosis, underlying malignancies of various types, milk-alkali syndrome, hypervitaminosis A or D, Dent disease and other tubulopathies. On the other hand, phosphate nephropathy is predominantly seen in patients...

Diagnose This! (October 16, 2017)

What is your diagnosis?       The photomicrograph shows a distended tubule with an intratubular crystalline cast with argyrophilia. While crystalline casts can be seen from calcium phosphate, calcium oxalate and others, the presence of argyrophilia on silver stain is characteristic for 2,8-Dihydroxyadenuria (DHA) crystals. 2,8-DHA is a rare, autosomal recessive trait caused by a genetic deficiency in adenine phosphoribosyltransferase (APRT). Accurate diagnosis is critical (especially in those with limited chronicity) as treatment exists that can ameliorate renal damage in some patients. And, in patients with the undiagnosed disease who undergo a transplant, the disease will reoccur unless pharmacologic...

2,8-Dihydroxyadenuria

Adenine phosphoribosyltransferase (APRT) deficiency results from an autosomal recessive enzyme defect of purine metabolism and leads to 2,8-dihydroxyadenine (2,8-DHA) crystalline nephropathy. The clinical presentation of this often misdiagnosed disease is widely variable among patients homozygous for APRT mutations, ranging from asymptomatic in some to reddish-brown diaper stains in infants to recurrent nephrolithiasis, and even CKD in the absence of nephrolithiasis. 2,8-DHA nephropathy has also been reported to recur in the renal allograft resulting in rapid allograft failure. Prompt and accurate diagnosis of this disorder is important so that treatment through pharmacologic inhibition of xanthine dehydrogenase can be initiated. The morphologic findings...