MON-248 HERBAL BITTER: A RARE CAUSE OF ACUTE TUBULOINTERSTITIAL NEPHRITIS

Abstract

Acute interstitial nephritis is an immunologically driven condition characterised by an inflammatory infiltrate in the renal interstitium. The use of herbal remedies has increased globally and has been described as a risk factor for the development of kidney injury, causing a variety of renal syndromes. We present a unique case of biopsy-proven acute interstitial nephritis following ingestion of an herbal bitter health drink, which was associated with a skin rash and eosinophilia. A 72-year-old-man presented with a 1-week history of general malaise, rash and fevers. His physical examination revealed a widespread maculopapular rash and pitting oedema to the knees but otherwise a normal examination including vital signs. His blood pressure on admission was 124/70. Four days into admission, his renal function deteriorated with a serum creatinine level rising to 411μmol/L (baseline of 98 μmol/L). One week into admission, he had a peak serum creatinine of 651 and was also oligouric. A renal biopsy revealed an interstitial infiltrate with a rich population of eosinophils. The findings were diagnostic of tubulointerstitial nephritis; the presence of eosinophils supporting a drug-induced cause. He had no recent alteration to his medications. On further questioning, the patient noted that one month prior to admission, he had started consuming an herbal bitter health drink. He was treated with intravenous methylprednisolone and a tapering dose of prednisolone, with the patient’s kidney function returning to baseline four weeks after the commencement of steroids. The herbal health drink ingested by the patient in this case, comprised of a combination of bitter herbs, consisting of a blend of seven herbal bitters. To the best of our knowledge, this is the first case of biopsy-proven acute interstitial nephritis induced by this multi-herbal health drink. This case report highlights the importance of taking a thorough medical history including establishing the use of over-the-counter medication and herbal remedies in the drug history. Furthermore, the importance of a prompt histological diagnosis in the form of a kidney biopsy is warranted, particularly in the case of drug-induced acute interstitial nephritis, as the mainstay of treatment involves cessation of the causative agent.