Rosuvastatin-Induced Acute Interstitial Nephritis
An 83-year-old man was admitted to our unit for rapidly worsening renal function 3 weeks following angioplasty of the left internal carotid artery. During this 3-week period his serum creatinine increased from 2.0 to 5.4 mg/dl. The patient had suffered from hypertension within the last 20 years and had chronic kidney disease with unremarkable urinalysis and diffuse peripheral vasculopathy. At the time of admission, he was being treated with an angiotensin receptor blocker (ARB), a dihydropyridine calcium channel blocker, aspirin and rosuvastatin (20 mg/day), which was prescribed following the carotid angioplasty. At admission the patient was afebrile, eupneic and mildly hypovolemic, showed normal diuresis and had a blood pressure of 110/60 mm Hg and a heart rate of 88 bpm. Laboratory tests were normal except for elevated serum creatinine (5.4 mg/dl) and BUN (73 mg/dl). Urinalysis showed no active sediment with mild proteinuria (500 mg/day). ANA, ENA, C3, C4, CH50, ANCA, cryoglobulinemia, rheumatoid factor, serum and urine protein immunofixation and free light-chain concentrations were all within the normal range. Kidney ultrasonography showed elevated echogenicity of the parenchyma and an increased renal resistance index (0.76) in the absence of renal artery stenosis. The ARB was discontinued and the patient received intravenous crystalloids for the next 72 h. At this time, the possibility of atheroembolic renal disease was excluded since the recent carotid angioplasty was performed through a femoral artery catheter, during which both an ophthalmologic examination for retinal cholesterol crystal emboli and dermatological manifestations were negative and did not show eosinophilia. However, because renal function did not recover (serum creatinine: 5.9 mg/dl), an echo-guided biopsy of the left kidney was performed. Light microscopy showed interstitial edema with lymphocyte infiltrate associated with tubulitis (fig. ). Electron microscopy evaluation was negative. Immunofluorescence was aspecific and not consistent. Based on these results, a diagnosis of acute tubulointerstitial nephritis was made.\nSince rosuvastatin was the most recently introduced drug, a possible relationship between the drug and AIN was considered. Thus, rosuvastatin was withdrawn, and oral prednisolone (1 mg/kg/day) was prescribed but rapidly tapered over a period of 4 weeks. The patient was discharged with conservative therapy, and after 8 weeks renal function values returned to baseline (serum creatinine 2 mg/dl, BUN 30 mg/dl, proteinuria 150 mg/24 h and urinalysis at polarized light microscopy was unremarkable).\nOne month later, the same ARB was reintroduced and, because of the high cardiovascular risk of the patient, a different statin (atorvastatin 20 mg/day) was prescribed. The patient is being regularly followed up at our outpatient service and, 6 months after the beginning of atorvastatin, has not shown any deterioration in renal functions.