Acute interstitial nephritis in patients with viperine snake bite: single center experience of a rare presentation.

Acute renal failure following vasculotoxic viperine snake bites is very common in South Asia. Acute tubular necrosis and acute cortical necrosis are the common findings, with acute interstitial nephritis (AIN) being a rare presentation. We conducted renal biopsies in all patients who were admitted in our institute with viperine snake bite-related acute kidney injury (AKI) and who did not improve after three weeks of supportive care. Patients who had findings of AIN on renal histology were included for this study. Of a total of 42 patients, there were five patients (11.9%) with AIN. Our series of five patients is the largest series of this rare presentation in the literature. All of these five patients had features of severe envenomation, severe AKI network stage of AKI and very high antivenom requirements. They had a very prolonged stay in the hospital, and four of the five patients developed chronic kidney disease on follow-up. The overall outcome in this group was worse as compared with those who did not have AIN. AIN following viperine snake bites is not a very rare presentation. The reason for the development of this pathology is unclear, but direct venom-related effects are possible. This presentation portends a poor overall long-term prognosis as demonstrated in our case series.