Purslane-induced oxalate nephropathy: case report and literature review

Abstract

Background: The kidney is particularly vulnerable to toxins due to its abundant blood supply, active tubular reabsorption, and medullary interstitial concentration. Currently, calcium phosphate-induced and calcium oxalate-induced nephropathies are the most common crystalline nephropathies. Hyperoxaluria may lead to kidney stones and progressive kidney disease due to calcium oxalate deposition leading to oxalate nephropathy. Hyperoxaluria can be primary or secondary. Primary hyperoxaluria is an autosomal recessive disease that usually develops in childhood, whereas secondary hyperoxaluria is observed following excessive oxalate intake or reduced excretion, with no difference in age of onset. Oxalate nephropathy may be overlooked, and the diagnosis is often delayed or missed owning to the physician's inadequate awareness of its etiology and pathogenesis. Herein, we discuss the pathogenesis of hyperoxaluria with two case reports, and our report may be helpful to make appropriate treatment plans in clinical settings in the future.

Case presentation: We report two cases of acute kidney injury, which were considered to be due to oxalate nephropathy in the setting of purslane (portulaca oleracea) ingestion. The two patients were elderly and presented with oliguria, nausea, vomiting, and clinical manifestations of acute kidney injury requiring renal replacement therapy. One patient underwent an ultrasound-guided renal biopsy, which showed acute tubulointerstitial injury and partial tubular oxalate deposition. Both patients underwent hemodialysis and were discharged following improvement in creatinine levels.

Conclusions: Our report illustrates two cases of acute oxalate nephropathy in the setting of high dietary consumption of purslane. If a renal biopsy shows calcium oxalate crystals and acute tubular injury, oxalate nephropathy should be considered and the secondary causes of hyperoxaluria should be eliminated.

Keywords: Acute kidney injury; Case report; Hyperoxaluria; Oxalate nephropathy; Portulaca oleracea; Purslane.

Fig. 1

Purslane is widely grown in the land

Fig. 2

Renal biopsy showing oxalate crystallization in Case 1. a Kidney biopsy tissue under hematoxylin and eosin staining (H&E, × 100). b Translucent calcium oxalate crystals in the renal tubules (black arrows) under light microscopy (H&E, × 200). c The same field as b is shown under the polarized light microscope, and the birefringent crystal is visible (× 200)