ORAL PRESENTATION

BACKGROUND : Membranous nephropathy secondary to heavy metal toxicity is known to occur in patients undergoing treatment with indigenous Indian medications. Here we studied the different renal pathologies that were identified among patients with a history of intake of indigenous Indian medications.

AIM OF THE STUDY : To study the various renal pathologies associated with the use of indigenous Indian medications and their clinical profile.

METHODS : This was an ambispective observational study conducted at Madras Medical College Chennai India between May 2021 and August 2022. All patients with nephrotic syndrome or unexplained acute kidney injury who underwent a kidney biopsy for diagnostic purposes and who provided a history of recent ingestion of indigenous medications were included in the study. Histopathological examination of the biopsy tissue was performed by a single nephro-pathologist and included light microscopy and immunofluorescence. Serum and urine samples of the patient were analyzed using mass spectrometry for heavy metals. Indigenous medications when available were also analyzed using inductive coupled plasma-optical emission spectrometer.

RESULTS : A total of 18 patients were enrolled in the study; the median age was 46 years (IQR 40 to 53) with female preponderance (n = 14; 77.7%). The median duration of indigenous medication intake was 5 months. Indications for these medications were asthma (n = 6), joint pain (n = 8), diabetes (n = 1), general ill health (n = 2), and allergic symptoms (n = 1). A total of 12 patients (66.6%) had urine and 7 patients (38.8%) had serum mercury levels exceeding normal limits. Four patients were able to provide the indigenous formulations that they had been taking. All four of these samples contained high levels of mercury. The renal biopsy findings included membranous nephropathy (n = 11), minimal change disease (n = 6), and mesangial proliferative glomerulonephritis (n = 1). Tissue staining for PLA2R was negative in patients with membranous nephropathy, but two patients were positive for NELL-1 on direct immunofluorescence. The median quantum of proteinuria was 5.3 grams per day. Four patients had acute kidney injury at presentation. Acute kidney injury recovered during follow-up. Seven patients achieved complete remission with conservative management, three patients received steroids and achieved complete remission, three patients in partial remission, two patients lost follow-up, and three patients are currently in conservative management awaiting remission.

CONCLUSIONS : The most common pathology noted in patients having a history of intake of Indigenous Indian medications was membranous nephropathy (61%). Most patients recovered completely after withdrawing the drugs. Steroid-responsiveness was documented in some cases that did not remit spontaneously. Limitation: Despite the temporal association between the use of indigenous Indian medications and various renal pathologies, it is not possible to attribute causality, given the small number of patients studied.