[Chronic interstitial nephritis in an 18-year-old due to intake of a compound analgesic].

BACKGROUND: Renal side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) are acute renal failure due to an impaired perfusion caused by inhibition of prostaglandin synthesis, acute allergic interstitial nephritis as well as acute toxic tubular necrosis. Moreover, chronic renal failure may occur due to a chronic interstitial nephritis or an analgesic nephropathy that is characterized by capillary sclerosis and papillary necrosis in addition to chronic interstitial nephritis. In contrast to acute renal insufficiency that may already occur after a single NSAID dose, analgesic nephropathy is a disease caused by long-term intake of NSAID compound analgesics and predominantly affects the middle and old age.

CASE REPORT: An 18-year-old patient with a 4-year history of NSAID compound analgesic intake presented to the urology department with right-sided flank pain and increased serum creatinine. An obstruction as well as nephrolithiasis were ruled out and the patient was referred to the medical department. Urinalysis showed leukocyturia, mild microhematuria as well as proteinuria of 2.2 g/day whereupon a diagnostic kidney biopsy was performed. Histology revealed a chronic nonpurulent destructive interstitial nephritis. After cessation of analgesic intake, the serum creatinine level fell to the normal range; however, a reduced creatinine clearance persisted indicating chronic renal damage.

CONCLUSION: The present case is remarkable in that chronic renal damage due to intake of a compound analgesic was already observed in an 18-year-old patient. In this context, the permission of NSAID compound analgesics and their free over-the-counter sale to adolescents need to be critically questioned.