Acute Kidney Injury

Table of Contents

Table of Contents

Mack Holmberg, MD
Expert Review – Raj Mehrota, MD, MS (University of Washington, Division of Nephrology)


  1. Develop a framework for differentiating the cause (pre/intra/post-renal) of acute kidney injury (AKI)
  2. Diagnose and manage common presentations for AKI using this framework

Teaching Instructions

Plan to spend at least 30 minutes preparing for this talk by using the Interactive Board for Learning/Preparing and clicking through the headings to see the pre/intra/post framework. This talk can be presented in two ways:

1. Project the “Interactive Board for Presentation”
2. Reproduce a drawing of the presentation on a whiteboard.

With either method, print out copies of the Learner’s Handout so they may follow along during the presentation and take notes as you expand on the pathophysiology and differential. Begin with reviewing the objectives for the session. Ask the learners how they know a patient has developed an AKI. We have defined it as an abrupt decrease in GFR which is characterized by a rise in Cr, often with decreased UOP. This is a good time to remind them of the importance of characterizing an AKI as non-oliguric, oliguric or anuric. The KDIGO criteria are much more specific but reliant on accurate measurement of recent UOP and Cr, and therefore not as clinically relevant for a patient presenting to clinic or the ED.

Before moving forward, ask the learners their framework for an AKI differential; if they don’t respond with pre/intra/post, then introduce it to them and proceed with asking which one-liner and accompanying labs are associated with which. Since intra-renal is much more involved, it is recommended that you cover pre/post-renal (left side of the screen) before moving on. Click on the Cases to reveal the clinical history, then click on “Etiology?” to reveal the respective schema. If you are recreating this talk on a whiteboard, simply provide the learners with the one-liners before writing the pre/intra/post. The entire talk will take 25-35 minutes to deliver.


Interactive Boards

For Learning

Use for self-directed learning and for preparing to present

For Teaching

Use for Presenting – there is less text and fewer pop-ups

Take Home Points

  1. Pre-renal AKI is diagnosed by suggestive clinical history and physical and, if oliguric, a FeNa <1%.
  2. Post-renal AKI is easily ruled in or out by evaluation for hydronephrosis with renal US.
  3. Intra-renal is identified by ruling out pre and post renal causes along with identifying active urine sediment.


Rangaswami J, Bhalla V, Blair JEA, et al. Cardiorenal Syndrome: Classification, Pathophysiology, Diagnosis, and Treatment Strategies: A Scientific Statement From the American Heart Association. Circulation. 2019;139(16):e840‐e878. doi:10.1161/CIR.0000000000000664

Levey AS, Eckardt K-U, Dorman NM, et al. Nomenclature for Kidney Function and Disease: Executive Summary and Glossary From a Kidney Disease: Improving Global Outcomes (KDIGO) Consensus Conference. Kidney International Reports. 2020;5(7):965-972. doi:10.1016/j.ekir.2020.03.027

Brandon Fainstad


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