Clinical Case Reports 2018; 6(5): 946--947

Case {#ccr31456-sec-0001}
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A 21‐year‐old otherwise healthy White woman was admitted to the hospital for treatment of atypical pneumonia following foreign travel. She was started on ceftriaxone and azithromycin to complete a 9‐day course of antibiotics. She developed acute kidney injury (AKI) with sudden worsening of serum creatinine from 0.98 mg/dL to 4.36 mg/dL on day 4, eventually requiring hemodialysis (Fig. [1](#ccr31456-fig-0001){ref-type="fig"}). The primary clinical diagnosis was acute tubular necrosis in the setting of sepsis. There was no rash, eosinophilia, pyuria, or eosinophiluria suggestive of acute interstitial nephritis (AIN). Moreover, the timing of creatinine up‐spike was not typical for AIN. Glomerulonephritis was unlikely in the absence of hematuria and significant albuminuria. Interestingly, renal biopsy was consistent with drug‐induced AIN (Fig. [2](#ccr31456-fig-0002){ref-type="fig"}). She was started on steroid therapy with complete recovery of renal function in 6 weeks.

![Graph depicting the trend of patient\'s serum creatinine and major clinical events.](CCR3-6-946-g001){#ccr31456-fig-0001}

![Renal biopsy demonstrating (A) normal glomerulus, which excludes glomerulonephritis; (B) diffuse interstitial inflammation, suggestive of AIN. Eosinophils are shown in the inset, which favor drug‐induced etiology.](CCR3-6-946-g002){#ccr31456-fig-0002}

AIN typically develops 7--10 days after drug exposure and presents with variable clinical features [1](#ccr31456-bib-0001){ref-type="ref"}. High index of suspicion for AIN should be maintained, even in the absence of "classic triad" of fever, rash, and eosinophilia [2](#ccr31456-bib-0002){ref-type="ref"}. Definitive diagnosis often requires renal biopsy [1](#ccr31456-bib-0001){ref-type="ref"}, [2](#ccr31456-bib-0002){ref-type="ref"}. In addition to prompt withdrawal of the offending agent, early initiation of corticosteroids has shown to be beneficial in improving renal outcomes, especially in severe cases [3](#ccr31456-bib-0003){ref-type="ref"}, [4](#ccr31456-bib-0004){ref-type="ref"}.

Informed Consent {#ccr31456-sec-0002}
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Informed consent has been obtained for the publication of this clinical image.

Conflict of Interest {#ccr31456-sec-0003}
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The authors have declared that no conflict of interest exists.

Authorship {#ccr31456-sec-0004}
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All the authors: made substantial contribution to the preparation of this manuscript. RC and MK: drafted the manuscript and performed literature search. OAO: provided input on patient management. XZ: provided pathology images and pertinent input. AK: revised the manuscript critically for important intellectual content as the attending physician on the case.
