Acute tubulointerstitial nephritis in Scotland.

BACKGROUND AND AIMS Acute tubulointerstitial nephritis (ATIN) is a potentially reversible cause of acute kidney injury with the majority of cases drug related. Our aims were to examine the incidence profile of patients with ATIN in Scotland and to assess the impact of corticosteroid treatment. DESIGN AND METHODS All adult patients with biopsy-proven ATIN, diagnosed between 2000 and 2012, presenting to renal units serving 1.9 of Scotland's 5 million population were included. Patient demographics, presenting, aetiologic and pathologic features, treatment given and outcome were extracted from patient records. RESULTS In total, 171 cases representing 4.7% of native renal biopsies were identified. Median serum creatinine (sCr) was 327 μmol/l at biopsy (106 μmol/l at baseline). Eosinophilia, fever or rash was present in 57% with all 3 in only 1.1%. Active urinary sediment was found in 68%. Aetiology appeared drug induced in 73%. Proton pump inhibitors (PPIs) were likely causative in almost as many cases as antibiotics (35% each) and were more frequently implicated than non-steroidal anti-inflammatory drugs (20%). Number of PPI-related cases paralleled the rising prescription of these drugs. Corticosteroids were prescribed in 59% of drug-induced ATIN (median sCr at biopsy: 356 μmol/l vs. 280 μmol/l in those managed conservatively). There was no difference in sCr at 1, 6 and 12 months, with similar proportions of both groups experiencing complete renal recovery (48% vs. 41%) and becoming dialysis dependent (10% in both). CONCLUSIONS Incidence of biopsy-proven ATIN in Scotland has been rising over the past decade with the majority of cases drug induced. Evidence supporting corticosteroid treatment is lacking.