A Pill Can Kill: Diclofenac-Induced Acute Interstitial Nephritis: A CaseReport

Background: Diclofenac is a commonly used non-steroidal anti-inflammatory drug, which is well known to have a causal association with drug-induced nephrotoxicity, specifically Acute Interstitial Nephritis (AIN). Case Presentation: We report a case of a mid-30-year-old healthy male who developed acute kidney injury following a single dose ingestion of 150 mg of a diclofenac tablet. The drug was administered since the patient had complaints of myalgia and back pain post-strenuous exercise. Upon presentation to the emergency room, his routine point of care laboratory investigation revealed an unexplained elevated serum creatinine level (3.13 mg/dl) with a daily progressive incline. Further urine analysis revealed the presence of AIN in the urine, with renal biopsy confirming AIN. Other renal imaging and ultrasound of the kidney showcased normal morphology with no abnormalities, thus ruling out other causes for renal impairment. Suspecting diclofenac to have contributed to AIN, causality and severity assessment was performed, indicating a probable adverse drug reaction. The patient was managed with pulse steroids for three days, following which renal function became normal. Conclusion: This case emphasizes that even a single dose of diclofenac can precipitate acute kidney injury, underscoring the importance of awareness of this reaction for early diagnosis, prompt discontinuation of the offending agent, and immediate initiation of immunosuppressive therapy.