Etiologies, Clinical Features, and Outcome of Oxalate Nephropathy

Abstract

Background: Oxalate nephropathy is a potentially underestimated cause of kidney failure characterized by massive deposition of calcium oxalate crystals in the renal parenchyma. The prevalence and modes of presentation of this entity are ill-defined. Methods: Here we report on the largest consecutive series of cases of adult oxalate nephropathy diagnosed on native kidney biopsies from January 2010 to December 2018 in the UCLouvain Kidney Disease Network. Results: We screened 2265 native kidney biopsies and identified 22 cases (1%) of oxalate nephropathy. Patients had a mean age at diagnosis of 61 years (AE20) and presented either with acute on chronic kidney disease (CKD) (62%) or with acute kidney injury (AKI) (38%). Mean serum creatinine at biopsy was 8.0 AE 4.5 mg/dl. Kidney biopsies showed abundant calcium oxalate crystal deposits, associated with acute interstitial nephritis and tubular necrosis, and variable degrees of interstitial fibrosis and tubular atrophy. Chronic pancreatitis and gastric bypass were the most common causes of oxalate nephropathy (48%). During a mean follow-up of 29 months, half of the patients (52%) progressed to kidney failure, all within the month following diagnosis. Higher serum creatinine level at presentation and interstitial fibrosis and tubular atrophy score were associated with progression to kidney failure. Conclusion: Oxalate nephropathy is the cause of kidney disease in 1% of consecutive native kidney biopsies and typically presents as acute on CKD or AKI. The prognosis of the disease is poor, with a high rate of kidney failure within the first month after the diagnosis.

Dietary Oxalate Intake and Kidney Outcomes

“…In addition, it was hypothesized that different forms of oxalate deposition may influence disease manifestation: severe acute supersaturation may cause massive crystal deposition, renal epithelial cell damage, inflammation and necrosis, resulting in AKI. On the contrary, less severe but persistent forms may generate chronic crystal deposition, especially in the distal tubule or collecting ducts, ending in CKD [108,109]. Although prospective studies are lacking, a large number of case reports suggested a causative role of dietary oxalate on acute kidney injury.…”

Critically ill, tubular injury, delayed early recovery: characteristics of acute kidney disease with renal oxalosis

“…This study describes characteristics of AKD with secondary renal oxalosis case series, which is clinically more common than PH, but a potentially underestimated disease. Oxalate crystals deposition in the kidney causes tubule obstruction and interstitial inflammation, leading to renal dysfunction [ 12 , 13 ]. As early as 1973, William R. Salyer and colleagues described oxalosis as a severe complication of chronic renal failure [ 14 ].…”

“…A recently published study reported oxalate nephropathy had a prevalence of 1% as the cause of native kidney disease. Disease origins from chronic pancreatitis and gastric bypass were the most common (48%) [ 13 ]. However, analysis of AKD with renal oxalosis in the present study showed a different etiological composition from that reported by Western researchers, where only 26.1% of patients having risk factors by enterogenous or excessive oxalate intake, but new AKD was regarded as the cause of oxalosis in these patients.…”

“…[ 15 ] and Buysschaert et al. [ 13 ] pointed out the poor prognosis of renal oxalosis, with more than half of the patients needing to rely on dialysis. Increasing data from PH, EH, and CKD cohort support the contribution of plasma and urine oxalate to CKD progression [ 21 , 28 ].…”

Acute Kidney Injury after Ingestion of a Native Southeast Asian Fruit as a Complementary Remedy

“…1 Ultrasound of the kidneys is usually unyielding in oxalate nephropathy as seen in observational studies. 3,4 Severe acute kidney failure was not uncommon and transient renal replacement therapy was required in 60-70%, 2 but prognosis was generally good with renal recovery within 2-8 weeks. 1 Oxalate nephropathy is uncommon and may be due to primary or secondary hyperoxaluria.…”