SOMETHING IS BREWING
Dr Kate Brotherton1, Dr Lachlan Clarke1, A/Prof Bobby Chacko1,2
1Nephrology and Transplantation Unit, John Hunter Hospital, Newcastle, Australia, 2School of Medicine and Public Health, University of Newcastle, Newcastle, Australia
Background: Kava plant root (piper methysticum) is an ingredient used in ceremonial drinks throughout Pacific and South Sea Island communities. Kava is made up of kavalactones; psychoactive compounds that act as central nervous system depressants. The rare occurrence of kavalactone toxicity manifests most commonly with hepatotoxicity and cases of myoglobinuria have been reported. Our case describes an association of significant kava tea ingestion with severe acute tubulo-interstitial nephritis.
Case Report: an 18-year-old male, without any medical comorbidities, presented with oliguric acute kidney injury after ingestion of fifteen cups of kava tea causing severe vomiting. His creatinine at admission was 223umolL and peaked at 96hrs post ingestion at 970umol/L despite intravenous fluid administration. His urine ACr was 196mg/mmol with microscopic haematuria, a creatinine kinase was 780U/L, C3 was mildly reduced (0.77g/L) with normal C4 and the remainder of a glomerulonephritis screen was negative. He did not have any evidence of hepatotoxicity but was bradycardic with a prolonged QT interval. A urine drug screen was negative for other substances. A kidney biopsy demonstrated severe acute tubulointerstitial nephritis without acute tubular necrosis or evidence of myoglobulin-related injury. He was commenced on oral corticosteroids and had complete recovery of his kidney function after two weeks, without requiring kidney replacement therapy. Toxicology analysis of the kava powder identified four different kavalactones without additional substances.
Conclusions: kavalactone toxicity, specifically nephrotoxicity, is a very rare complication of kava ingestion. This case describes a pathological mechanism for kava nephrotoxicity, supported by histopathologic findings, that has not yet been described in the literature.