Case Studies

 Case 9.10 Acute tubulointerstitial nephritis

A 37-year-old woman was admitted to hospital with a diagnosis of bacterial endocarditis. Blood cultures grew Streptococcus faecalis. She was treated with intravenous gentamicin and ampicillin with considerable improvement. However, on the 12th day of treatment, she developed a further fever and a macular rash on her trunk and limbs. Her white-cell count was normal with an absolute eosinophil count of 0.32 x 10⁹/l. Further blood cultures were negative but her serum creatinine rose from 140µmol/l (NR 60-120) to 475µmol/l over the next 3 days, with a rise in the eosinophil count to 0.92 x 10⁹/l. Serum complement levels were normal. A renal biopsy showed marked interstitial oedema and infiltration of tubules by mononuclear cells, neutrophils and eosinophils. A diagnosis of acute TIN, probably drug induced, was made; antibiotics were discontinued and prednisolone started instead. Her serum creatinine rose to a peak of 640µmol/l but she never became oliguric and did not require dialysis. After 3 days of steroids, her renal function began to improve and the eosinophil count fell.