Allergic Interstitial Nephritis Manifesting as a Striated Nephrogram

Abstract

Allergic interstitial nephritis (AIN) is an underdiagnosed cause of acute kidney injury (AKI). Guidelines suggest that AIN should be suspected in a patient who presents with an elevated serum creatinine and a urinalysis that shows white cells, white cell casts, or eosinophiluria. Drug-induced AIN is suspected if AKI is temporally related to the initiation of a new drug. However, patients with bland sediment and normal urinalysis can also have AIN. Currently, a definitive diagnosis of AIN is made by renal biopsy which is invasive and fraught with risks such as bleeding, infection, and hematoma. Additionally, it is frequently unclear when a kidney biopsy should be undertaken. We describe a biopsy proven case of allergic interstitial nephritis which manifested on contrast enhanced Magnetic Resonance Imaging (MRI) as a striated nephrogram. Newer and more stable macrocyclic gadolinium contrast agents have a well-demonstrated safety profile. Additionally, in the presentation of AKI, gadolinium contrast agents are safe to administer in patients who demonstrate good urine output and a downtrending creatinine. We propose that the differential for a striated nephrogram may include AIN. In cases in which the suspicion for AIN is high, this diagnostic consideration may be further characterized by contrast enhanced MRI.

Infliximab-Induced Tubulointerstitial Nephritis with Image Findings of Striated Nephrogram in Crohn’s Disease

“…The contrast-enhanced high absorption region is formed by the accumulation and concentration of the contrast agent due to mechanical compression against the col- lecting duct from the tubule associated with interstitial edema, along with drug-induced direct dysfunction of the renal tubule. Regarding patients who present with bilateral striated nephrogram, TIN, acute pyelonephritis, and autosomal recessive polycystic kidney disease have been reported (Moinuddin et al 2015). The cause of TIN has been noted to be drug-induced, infectious, and idiopathic in 71%, 15.6%, and 7.8% of cases, respectively (Baker and Pusey 2004).…”