Acute Interstitial Nephritis in the Pediatric Population: A Review of Etiologic Associations, Histologic Findings, and Clinical Outcome.

BACKGROUND

Acute interstitial nephritis (AIN) is an infrequent cause of acute kidney injury in the pediatric population with a broad range of etiologies. This retrospective review attempts to characterize AIN in the pediatric population, delineate etiologic factors, histologic features, and clinical outcome.

MATERIALS AND

METHODS

Institutional pathology reports were queried for a diagnosis of AIN between 1/2010 and 10/2021. Archived slides and reports and clinical records were reviewed.

RESULTS

Twenty-four patients were identified whose ages ranged from 5 to 20 years. A 8 cases (37.5%) were characterized as tubulointerstitial nephritis and uveitis (TINU), 4 cases (16.7%) were associated with an autoimmune disease, 4 cases (16.7%) were likely drug induced, and 8 cases (37.5%) had unclear etiology.

DISCUSSION: Although all cases of drug induced interstitial nephritis contained eosinophils they were not exclusive to drug induced interstitial nephritis. A prominent plasma cell infiltrate was seen in both cases of Sjögren's associated interstitial nephritis. The vast majority (n = 18, 75%) showed an improved serum creatinine (<1 mg/dL) 1 year post diagnosis/at last follow-up. In this pediatric series of AIN, TINU contributed to a large subset of cases with known etiologies. On follow up, majority of the cases demonstrated recovery of renal function.