Oxalate nephropathy analysis: A case series from a single center

Enteric hyperoxaluria is a common cause of secondary oxalate nephropathy (ON), and pancreatic exocrine insufficiency (PEI) is one of the causes of enteric hyperoxaluria. Due to atypical clinical symptoms or elusive etiology, the incidence of PEI is often underestimated. For patients with ON, it is crucial to screen for PEI and its etiology.

Cases with pathological diagnosis of ON and acute kidney injury (AKI) during January 2023 to December 2023 were retrospectively enrolled. The datasets of clinical manifestation, kidney pathology, treatment, and prognosis were collected. Fecal elastase-1 was employed to test pancreatic exocrine function. Genetic testing, bioinformatics analyses, and minigene splicing assay were performed on patients diagnosed with chronic pancreatitis (CP).

Among 6 patients diagnosed with ON, 2 patients had increased intake of oxalate/oxalate precursors, 2 patients had increased intestinal oxalate absorption due to PEI, one patient both had increased intake and absorption, with one case being of unknown etiology. Among the 3 patients with PEI, 2 were diagnosed with CP and genetic testing further discovered mutations in SPINK1 or PRSS1 . Renal function was completely recovered in 2 patients, progressed to end-stage kidney disease in 1, and the remaining patients showed varying degrees of kidney function recovery.

A kidney biopsy can help physicians determine the cause of AKI. Once diagnosed with secondary ON, screening for PEI is recommended, especially when considering enteric hyperoxaluria as the cause. The etiology of PEI should be investigated. Genetic testing is advised for CP patients without clear etiology or recurrent acute pancreatitis.