A case report of acute interstitial nephritis caused by cotton phenol

BACKGROUND Cotton phenol is a yellowish-brown polyphenol hydroxybinaphthyl aldehyde compound mainly found in the roots, stems, leaves and seeds of cotton; a plant of the mallow family that has been widely used in the study of antifertility and antitumor drugs. However, there has been no report of serious renal injuries caused by cotton phenol. We report a case of granulomatous acute interstitial nephritis caused by exposure to large amounts of cotton phenol. CASE DESCRIPTION The patient was a 56-year-old male with nausea and a blood creatinine level of 4.95 mg/dL 2 month prior to admission. He was admitted to the hospital with worsening nausea, blood creatinine level of 7.21 mg/dL, and a renal puncture biopsy suggesting granulomatous acute interstitial nephritis. The patient had no specific past medical history. Laboratory tests (double-stranded DNA, antineutrophil cytoplasmic antibody, extractable nuclear antigen, rheumatoid subunit, serum and urine protein electrophoresis, complement levels, immunoglobulin subclasses, streptococcal serology, and hepatitis B and C serology were negative, normal or undetectable. Follow-up history revealed that the patient receives large quantities of cotton phenol at work. The diagnosis was granulomatous acute interstitial nephritis induced by exposure to cotton phenol. Treatment was volume management, maintenance of a stable internal environment, and glucocorticoid activation. Blood creatinine level gradually decreased to 1.86 mg/dL after 3 month and his condition improved. CONCLUSIONS Physicians encountering patients with acute interstitial nephritis of uncertain etiology are obligated to conduct a prompt and comprehensive history review. Special attention should be given to cotton phenol and its derivatives as they may potentially act as nephrotoxic agents. The application of glucocorticoids in the treatment of acute interstitial nephritis remains a subject of debate. However, in this particular case, the patient exhibited a rapid restoration of renal function following the administration of glucocorticoids.