Case history
Case history
A 67-year-old man has been receiving amoxicillin treatment for bronchitis for 2 weeks. He develops a macular rash on his neck, torso, and back. The amoxicillin is therefore changed to cephalexin for an additional 7 days. The rash resolves, but he returns complaining of fatigue and a low-grade temperature that has persisted despite the resolution of bronchitis. He has not noticed any changes in his urine output. He has a history of hypertension, hyperlipidemia, a previous myocardial infarction (6 years ago), and symptoms suggestive of gastric reflux. There is no history of renal disease. He has been on a stable regimen of lisinopril, metoprolol, simvastatin, and omeprazole. Physical exam reveals a blood pressure of 140/85 mmHg, pulse 68 bpm regular, temperature 100°F (37.8°C), and respirations of 16/minute. Examination is normal. Blood test results show an elevated serum creatinine value (2.0 mg/dL [177 micromol/L] from a level of 0.9 mg/dL [80 micromol/L] 3 months ago).
Other presentations
The loss of kidney function may be acute (within 7 days), characterized by acute kidney injury (AKI), in about half the cases, and subacute (between 7 and 90 days), characterized by acute kidney disease (AKD), in the other half.[2] Classic allergic features such as fever, rash, and eosinophilia are noted in <10% of people with acute interstitial nephritis (AIN).[3]
Patients with NSAID-induced AIN may present with AKI accompanied by edema secondary to concurrent nephrotic syndrome.[1]
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