The Number of Calcium Oxalate Deposits Significantly Correlate with Elevated Serum Creatinine Levels in Calcium Oxalate Nephropathy.
American Journal of Clinical Pathology
Calcium oxalate nephropathy is defined as acute and/or chronic decrease in renal function due to deposition of calcium oxalate crystals in renal tubules leading to acute tubular injury, acute or chronic interstitial nephritis, and elevated serum creatinine levels. However, the correlation between serum creatinine (SCr) levels and the number of calcium oxalate deposits has not been well described in the literature. Methods/Case Report
Eight controls with mild to moderate acute tubular injury and 10 cases with calcium oxalate nephropathy (calcium group) were selected for the study. The patient’s SCr values were obtained from electronic medical records and the number of polarizable calcium oxalate crystal deposits in the lumen of proximal tubules seen on Hematoxylin & Eosin stained slides at 40x high power field were recorded for each biopsy. Umpired student T-test was used to compare the two groups. Linear regression analysis was used to correlate SCr and the number of calcium oxalate deposits. Results (if a Case Study enter NA)
Mean ages were not significantly different between two groups (49 ± 8 years in controls and 64 ± 6 years in calcium group). SCr was significantly higher in the calcium group (5.97 ± 0.68 mg/dl*) than in the control group (2.59 ± 0.37 mg/dl). No calcium oxalate deposits were seen in any of the controls, but the number of calcium oxalate deposits ranged from 3 to 7 in the calcium group (Table 1). In our study, we found a significant linear correlation between SCr and the number of crystals/high power field, when all cases were taken together (r value = 0.783, p value = 0.0002*). Conclusion
Our data suggest that there is a direct association between the number of calcium oxalate crystals in proximal tubules with the severity of renal dysfunction. Although the etiologies for calcium oxalate nephropathy can be multifactorial, counting the deposit number on renal biopsies is simple method to predict SCr levels.
Kumar S, Zhang P. The number of calcium oxalate deposits significantly correlate with elevated serum creatinine levels in calcium oxalate nephropathy. Am J Clin Pathol. 2022 Nov;158(Suppl 1):S155. doi: 10.1093/ajcp/aqac126.330.
Annual Meeting of the American Society for Clinical Pathology, Chicago, IL, September 7-9, 2022.