1/#Medtwitter friends, we are thrilled to share a #tweetorial courtesy of @StephenieLe11 and inspired by @DrDanRestrepo's episode on intrarenal AKI #FOAMed
clinicalproblemsolving.com/2019/03/21/epi…

2/30M presented with MSSA native tricuspid valve endocarditis and lower extremity edema was found to have AKI. What are the renal manifestations of endocarditis?

3/There are numerous causes of AKI in patients with endocarditis. Let us know if you think of others!

4/UA showed trace protein, 1+ blood, 12 RBCs and 5 WBCs. The UA is a poor person’s kidney biopsy and it’s imperfect test characteristics mean that it can only be used as a guide to the Dx.

5/As @DxRxEdu taught us, trend your UAs like you trend troponin; repeat UAs consistent with a singular diagnosis offer better test characteristics.

6/Here is how the UA can be helpful. Many thanks to @naomi_anker for her review!

7/CT showed normal sized kidneys & no evidence of infarction. Spot urine Pr/Cr ratio was 1; albumin made up a small fraction of his proteinuria (consistent across several UAs). Urine microscopy showed muddy brown casts (image below) & no dysmorphic RBCs, RBC casts, or WBC casts

8/What is your leading diagnosis?

9/ Low grade non-albumin proteinuria & muddy brown casts were most suggestive of ATN. Infection related GN wasn’t definitively ruled out. Regardless, addressing the underlying infection would be the principal of Rx. With Abx, his kidney function gradually returned to baseline.

10/ Main take away: the UA, protein/creatinine ratio and microscopy can be incredibly helpful guides in the workup of AKI. Download a PDF version of the schema here
clinicalproblemsolving.com/dx-schema-urin…

11/If you enjoyed this #tweetorial, direct message us a snapshot of your retweet for a bonus schema on tubular diseases!
@dminter89 @Sharminzi @ArsalanMedEd @DxRxEdu @rabihmgeha