Membranous nephropathy due to chronic mercury poisoning from traditional Indian medicines: report of five cases

Abstract

Mercury contained in traditional medicines can cause chronic poisoning, which can cause membranous nephropathy (MN). We report five cases of nephrotic syndrome caused by MN with evidence of chronic mercury poisoning due to consumption of traditional Indian medicines such as Siddha and Ayurveda, which to our knowledge are the first such reports. All patients were seronegative for antibodies against phospholipase A2 receptor (PLA2R). Two patients, who had severe nephrotic syndrome, had received Siddha medicine for prolonged period and oral chelation with dimercaptopropane-1-sulfonic acid was successful in eliminating mercury, resulting in an improvement in nephrotic state in these patients. We suggest that mercury poisoning should be entertained in patients with anti-PLA2R antibody-negative MN, with history of consumption of traditional Indian medicines.

Keywords: dimercaptopropane-1-sulfonic acid; membranous nephropathy; mercury; nephrotic syndrome; traditional Indian medicine.

FIGURE 1:

Periodic acid–Schiff staining of renal biopsy specimen showing uniformly thickened capillary walls (A) and silver staining of renal biopsy specimen from index case showing fine linear spikes (B).

FIGURE 2:

Hematoxylin and eosin staining showing segmental endothelial proliferation (arrow) with infiltration by numerous neutrophils and uniform thickening of capillary basement membrane (A) and Periodic acid–Schiff staining showing partial fibroepithelial crescent (arrow) from renal biopsy of Case 2 (B).

FIGURE 3:

EM picture from Case 2, showing subepithelial electron dense deposits.