Renal Case: 35-year-old Woman with Increased Serum Creatinine

00:01 Let's move on to another case.

00:03 We have a 35-year-old woman with an increase in serum creatinine from 0.7 to 3.2 mg/dL.

00:10 She's currently in the ICU receiving nafcillin which is a penicillin by continuous infusion for Staph. aureus endocarditis.

00:18 On physical exam, she's febrile and she has a very interesting erythematous, maculopapular rash over her thorax and extremities.

00:28 When we look at her laboratory data, we see that her serum creatinine is now 3.2 mg/dL, you can see that that's elevated.

00:35 And her complete blood count has an increased number of eosinophils on the differential.

00:40 Her urine analysis shows white blood cells and white blood cell casts but the urine culture is negative.

00:48 So the question is, what type of acute kidney injury does this woman have? Let's go through our case and see if we can answer that question.

00:55 So looking at our history, it's very important to notice that temporal correlation with the administration of nafcillin and the rise in serum creatinine.

01:05 So essentially, she gets nafcillin, couple of days later we have an increase in serum creatinine.

01:10 Look at her physical exam, too.

01:12 On physical exam, she has an erythematous, maculopapular rash which really is also giving us a clue to the diagnosis.

01:20 Moving on then to our laboratory data, we can see that she has an eosinophilia and that is really suggestive of an allergic or hypersensitivity process.

01:31 So we combine that with her AKI and her physical exam, that really suggest allergic interstitial nephritis.

01:39 And the pyuria that she has - so that's the white cells at her urine and that white blood cell cast in the absence of a positive urine culture, highly suggestive of an interstitial nephritis.

01:51 So, the answer is of course is acute allergic interstitial nephritis.