{"version":"1.0.0","segments":[{"startTime":0.001,"endTime":3.277,"body":"♪ (music) ♪"},{"startTime":3.278,"endTime":5.579,"body":"(Cathy) Hi, welcome to \u003ci\u003eHarrison's Podclass\u003c/i\u003e"},{"startTime":5.58,"endTime":8.521,"body":"where we discuss important concepts"},{"startTime":5.58,"endTime":8.521,"body":"in internal medicine."},{"startTime":8.521,"endTime":9.904,"body":"I'm Cathy Handy."},{"startTime":9.904,"endTime":11.304,"body":"And I'm Charlie Wiener,"},{"startTime":11.304,"endTime":13.761,"body":"and we're coming to you"},{"startTime":11.304,"endTime":13.761,"body":"from the Johns Hopkins School of Medicine."},{"startTime":13.762,"endTime":16.689,"body":"[music]"},{"startTime":16.69,"endTime":20.149,"body":"It is hospital day five"},{"startTime":16.69,"endTime":20.149,"body":"for a 65-year-old patient"},{"startTime":20.15,"endTime":23.436,"body":"with prerenal azotemia"},{"startTime":20.15,"endTime":23.436,"body":"secondary to dehydration."},{"startTime":23.436,"endTime":27.691,"body":"His creatinine was initially"},{"startTime":23.436,"endTime":27.691,"body":"3.6 milligrams per deciliter on admission,"},{"startTime":27.692,"endTime":31.388,"body":"but it has improved,"},{"startTime":27.692,"endTime":31.388,"body":"today to 2.1 milligrams per deciliter."},{"startTime":31.389,"endTime":33.444,"body":"He complains of mild lower back pain"},{"startTime":33.445,"endTime":36.931,"body":"and you prescribe naproxen"},{"startTime":33.445,"endTime":36.931,"body":"to be taken intermittently."},{"startTime":36.931,"endTime":41.556,"body":"By what mechanism might this drug"},{"startTime":36.931,"endTime":41.556,"body":"further impair his renal function?"},{"startTime":41.566,"endTime":43.75,"body":"So, Cathy, let's talk about this case."},{"startTime":43.751,"endTime":46.718,"body":"(Cathy) Alright, so the only patient"},{"startTime":43.751,"endTime":46.718,"body":"factors that we get in this case are"},{"startTime":46.719,"endTime":48.853,"body":"that it's a 65-year-old man,"},{"startTime":48.854,"endTime":51.617,"body":"and the symptoms that came on"},{"startTime":48.854,"endTime":51.617,"body":"are low back pain."},{"startTime":51.618,"endTime":54.617,"body":"And we don't know whether or not"},{"startTime":51.618,"endTime":54.617,"body":"they're acute or chronic,"},{"startTime":54.618,"endTime":58.125,"body":"but we're treating"},{"startTime":54.618,"endTime":58.125,"body":"with naproxen for those symptoms."},{"startTime":58.126,"endTime":60.102,"body":"The injury that he already has,"},{"startTime":60.103,"endTime":62.394,"body":"which also contributes"},{"startTime":60.103,"endTime":62.394,"body":"to the host factors are"},{"startTime":62.395,"endTime":64.346,"body":"that he has acute kidney injury"},{"startTime":64.346,"endTime":67.568,"body":"thought to be attributed to dehydration"},{"startTime":64.346,"endTime":67.568,"body":"which is a reversible cause,"},{"startTime":67.569,"endTime":69.791,"body":"and we see that there's"},{"startTime":67.569,"endTime":69.791,"body":"already been some improvement"},{"startTime":69.791,"endTime":73.005,"body":"from 3.6 serum creatinine down to 2.1."},{"startTime":73.007,"endTime":76.165,"body":"So, now we need to talk"},{"startTime":73.007,"endTime":76.165,"body":"about naproxen which is an NSAID,"},{"startTime":76.166,"endTime":78.819,"body":"so a non-steroidal anti-inflammatory drug,"},{"startTime":78.819,"endTime":81.277,"body":"and that does have"},{"startTime":78.819,"endTime":81.277,"body":"an impact on the kidney."},{"startTime":81.277,"endTime":83.53,"body":"(Charlie) So, let's read over"},{"startTime":81.277,"endTime":83.53,"body":"the possible options here"},{"startTime":83.532,"endTime":84.984,"body":"that are listed in the question."},{"startTime":84.985,"endTime":87.506,"body":"And remember the stem says,"},{"startTime":87.507,"endTime":91.945,"body":"\"By what mechanism might this drug"},{"startTime":87.507,"endTime":91.945,"body":"further impair his renal function?\""},{"startTime":91.946,"endTime":96.644,"body":"Option A is afferent arteriolar"},{"startTime":91.946,"endTime":96.644,"body":"vasoconstriction,"},{"startTime":96.645,"endTime":100.869,"body":"option B is afferent arteriolar"},{"startTime":96.645,"endTime":100.869,"body":"vasodilation,"},{"startTime":100.87,"endTime":105.552,"body":"option C is efferent arteriolar"},{"startTime":100.87,"endTime":105.552,"body":"vasoconstriction,"},{"startTime":105.553,"endTime":109.804,"body":"option D is proximal tubular toxicity,"},{"startTime":109.805,"endTime":113.097,"body":"and option E is ureteral obstruction."},{"startTime":113.888,"endTime":115.966,"body":"So Cathy, let's review briefly"},{"startTime":115.967,"endTime":119.472,"body":"what is meant by afferent"},{"startTime":115.967,"endTime":119.472,"body":"and efferent arteriolar"},{"startTime":119.473,"endTime":121.409,"body":"vasoactivity in the kidney"},{"startTime":121.409,"endTime":122.997,"body":"and how is that relevant."},{"startTime":122.998,"endTime":127.099,"body":"(Cathy) Okay, so the afferent arteriole"},{"startTime":122.998,"endTime":127.099,"body":"is upstream of the glomerulus"},{"startTime":127.1,"endTime":128.362,"body":"and feeds the glomerulus"},{"startTime":128.363,"endTime":131.148,"body":"and it can really"},{"startTime":128.363,"endTime":131.148,"body":"either constrict or vasodilate."},{"startTime":131.149,"endTime":134.697,"body":"If you constrict the afferent arteriole"},{"startTime":131.149,"endTime":134.697,"body":"then you decrease the blood supply"},{"startTime":134.698,"endTime":136.483,"body":"and the results in GFR."},{"startTime":136.487,"endTime":139.44,"body":"And if you vasodilate"},{"startTime":136.487,"endTime":139.44,"body":"the afferent arteriole,"},{"startTime":139.441,"endTime":143.206,"body":"then you increase the blood supply"},{"startTime":139.441,"endTime":143.206,"body":"and the result in GFR."},{"startTime":143.206,"endTime":146.573,"body":"The efferent arteriole is downstream"},{"startTime":143.206,"endTime":146.573,"body":"and the exact opposite happens,"},{"startTime":146.574,"endTime":149.106,"body":"so constriction will increase the GFR"},{"startTime":149.107,"endTime":153.318,"body":"and vasodilation of the efferent"},{"startTime":149.107,"endTime":153.318,"body":"arteriole will decrease the GFR."},{"startTime":153.719,"endTime":156.741,"body":"Now, in the setting of kidney injury,"},{"startTime":153.719,"endTime":156.741,"body":"the response is naturally"},{"startTime":156.742,"endTime":161.025,"body":"that the afferent arteriole"},{"startTime":156.742,"endTime":161.025,"body":"will vasodilate to preserve GFR."},{"startTime":161.026,"endTime":162.302,"body":"(Charlie) So based on that,"},{"startTime":162.303,"endTime":164.215,"body":"we can already"},{"startTime":162.303,"endTime":164.215,"body":"eliminate two of the choices."},{"startTime":164.216,"endTime":168.477,"body":"Because answer B,"},{"startTime":164.216,"endTime":168.477,"body":"vasodilation of the afferent arteriole,"},{"startTime":168.478,"endTime":171.877,"body":"and answer C, vasoconstriction"},{"startTime":168.478,"endTime":171.877,"body":"of the efferent arteriole,"},{"startTime":171.888,"endTime":176.299,"body":"will both increase GFR, and therefore"},{"startTime":171.888,"endTime":176.299,"body":"would not impair renal function."},{"startTime":176.3,"endTime":177.761,"body":"They would actually help it, right?"},{"startTime":177.762,"endTime":179.229,"body":"(Cathy) Right, that's exactly right."},{"startTime":179.229,"endTime":183.799,"body":"So, now if we go back to the impact"},{"startTime":179.229,"endTime":183.799,"body":"that NSAIDs would have on renal perfusion,"},{"startTime":183.8,"endTime":188.647,"body":"this would sort of fall under the category"},{"startTime":183.8,"endTime":188.647,"body":"of prerenal causes of acute kidney injury."},{"startTime":188.648,"endTime":191.031,"body":"And NSAIDs act on prostaglandins"},{"startTime":191.032,"endTime":194.88,"body":"which exert vasodilatory action"},{"startTime":191.032,"endTime":194.88,"body":"on the afferent arterioles."},{"startTime":194.881,"endTime":198.939,"body":"So, when you block the prostaglandins"},{"startTime":194.881,"endTime":198.939,"body":"like PG and prostacyclin,"},{"startTime":198.94,"endTime":200.299,"body":"which happens with NSAIDs,"},{"startTime":200.3,"endTime":202.386,"body":"then you get loss of vasodilation"},{"startTime":202.386,"endTime":205.453,"body":"and therefore constriction"},{"startTime":202.386,"endTime":205.453,"body":"of the afferent arteriole,"},{"startTime":205.454,"endTime":207.851,"body":"and that results in a decrease in GFR,"},{"startTime":207.852,"endTime":209.574,"body":"so the answer is A."},{"speaker":"(Charlie) So the answer is A","startTime":209.575,"endTime":214.09,"body":"constriction of the afferent arteriole"},{"speaker":"(Charlie) So the answer is A","startTime":214.091,"endTime":218.363,"body":"due to inhibition"},{"speaker":"(Charlie) So the answer is A","startTime":214.091,"endTime":218.363,"body":"of prostaglandin synthesis by the naproxen"},{"speaker":"(Charlie) So the answer is A","startTime":218.364,"endTime":222.394,"body":"could actually exacerbate his acute"},{"speaker":"(Charlie) So the answer is A","startTime":218.364,"endTime":222.394,"body":"renal injury or his acute kidney injury"},{"speaker":"(Charlie) So the answer is A","startTime":222.395,"endTime":223.793,"body":"by making the kidney think"},{"speaker":"(Charlie) So the answer is A","startTime":223.793,"endTime":226.323,"body":"that the glomerulus"},{"speaker":"(Charlie) So the answer is A","startTime":223.793,"endTime":226.323,"body":"is being under profuse."},{"speaker":"(Charlie) So the answer is A","startTime":226.323,"endTime":227.894,"body":"- (Charlie) Is that correct?"},{"speaker":"(Charlie) So the answer is A","startTime":226.323,"endTime":227.894,"body":"- (Cathy) That's correct."},{"speaker":"(Charlie) So the answer is A","startTime":227.895,"endTime":230.008,"body":"So B and C we already said were wrong,"},{"speaker":"(Charlie) So the answer is A","startTime":230.008,"endTime":232.228,"body":"and then just to go"},{"speaker":"(Charlie) So the answer is A","startTime":230.008,"endTime":232.228,"body":"over the other choices."},{"speaker":"(Charlie) So the answer is A","startTime":232.228,"endTime":235.218,"body":"D, which talks about"},{"speaker":"(Charlie) So the answer is A","startTime":232.228,"endTime":235.218,"body":"proximal tubular toxicity can happen"},{"speaker":"(Charlie) So the answer is A","startTime":235.219,"endTime":237.719,"body":"if NSAIDs are taken"},{"speaker":"(Charlie) So the answer is A","startTime":235.219,"endTime":237.719,"body":"for a really long periods of time"},{"speaker":"(Charlie) So the answer is A","startTime":237.72,"endTime":241.06,"body":"or other drugs like antibiotics"},{"speaker":"(Charlie) So the answer is A","startTime":237.72,"endTime":241.06,"body":"can also cause that,"},{"speaker":"(Charlie) So the answer is A","startTime":241.061,"endTime":242.918,"body":"but that's not the case here."},{"speaker":"(Charlie) So the answer is A","startTime":242.919,"endTime":246.346,"body":"And then obstruction"},{"speaker":"(Charlie) So the answer is A","startTime":242.919,"endTime":246.346,"body":"is usually caused by mass effect"},{"speaker":"(Charlie) So the answer is A","startTime":246.347,"endTime":248.306,"body":"which wouldn't be caused by NSAIDs,"},{"speaker":"(Charlie) So the answer is A","startTime":248.307,"endTime":251.123,"body":"and it also shouldn't really"},{"speaker":"(Charlie) So the answer is A","startTime":248.307,"endTime":251.123,"body":"cause acute kidney injury"},{"speaker":"(Charlie) So the answer is A","startTime":251.124,"endTime":253.378,"body":"unless there's pre-existing disease."},{"speaker":"(Charlie) So the answer is A","startTime":253.379,"endTime":257.067,"body":"(Charlie) So, in summary this question"},{"speaker":"(Charlie) So the answer is A","startTime":253.379,"endTime":257.067,"body":"highlights the impact of NSAIDs"},{"speaker":"(Charlie) So the answer is A","startTime":257.069,"endTime":258.175,"body":"on renal perfusion,"},{"speaker":"(Charlie) So the answer is A","startTime":258.176,"endTime":260.644,"body":"such that they should be used"},{"speaker":"(Charlie) So the answer is A","startTime":258.176,"endTime":260.644,"body":"in caution in patients"},{"speaker":"(Charlie) So the answer is A","startTime":260.647,"endTime":263.044,"body":"with possible impaired renal perfusion,"},{"speaker":"(Charlie) So the answer is A","startTime":263.045,"endTime":266.791,"body":"such as elderly patients or other patients"},{"speaker":"(Charlie) So the answer is A","startTime":263.045,"endTime":266.791,"body":"with chronic kidney injury,"},{"speaker":"(Charlie) So the answer is A","startTime":266.792,"endTime":268.501,"body":"and probably are not the best choice"},{"speaker":"(Charlie) So the answer is A","startTime":268.501,"endTime":270.951,"body":"for post-operative pain"},{"speaker":"(Charlie) So the answer is A","startTime":268.501,"endTime":270.951,"body":"in this demographic."},{"speaker":"(Charlie) So the answer is A","startTime":270.951,"endTime":272.797,"body":"- (Charlie) Is that true?"},{"speaker":"(Charlie) So the answer is A","startTime":270.951,"endTime":272.797,"body":"- (Cathy) I agree completely."},{"speaker":"(Charlie) So the answer is A","startTime":272.798,"endTime":274.178,"body":"(Charlie) So, in this case, Cathy,"},{"speaker":"(Charlie) So the answer is A","startTime":274.179,"endTime":277.123,"body":"if this man were having pain"},{"speaker":"(Charlie) So the answer is A","startTime":274.179,"endTime":277.123,"body":"that was symptomatic enough"},{"speaker":"(Charlie) So the answer is A","startTime":277.123,"endTime":279.322,"body":"such that you did want"},{"speaker":"(Charlie) So the answer is A","startTime":277.123,"endTime":279.322,"body":"to give him something"},{"speaker":"(Charlie) So the answer is A","startTime":279.323,"endTime":280.966,"body":"what agents might you consider"},{"speaker":"(Charlie) So the answer is A","startTime":280.967,"endTime":282.223,"body":"given that we've already decided"},{"speaker":"(Charlie) So the answer is A","startTime":282.224,"endTime":284.699,"body":"that non-steroidals"},{"speaker":"(Charlie) So the answer is A","startTime":282.224,"endTime":284.699,"body":"are probably a bad choice."},{"speaker":"(Charlie) So the answer is A","startTime":284.7,"endTime":287.716,"body":"(Cathy) So, you can try something topical"},{"speaker":"(Charlie) So the answer is A","startTime":284.7,"endTime":287.716,"body":"like a lidocaine patch"},{"speaker":"(Charlie) So the answer is A","startTime":287.717,"endTime":289.129,"body":"if it was something focal,"},{"speaker":"(Charlie) So the answer is A","startTime":289.13,"endTime":291.002,"body":"or if you wanted to use a systemic drug,"},{"speaker":"(Charlie) So the answer is A","startTime":291.003,"endTime":293.168,"body":"you could try something"},{"speaker":"(Charlie) So the answer is A","startTime":291.003,"endTime":293.168,"body":"like acetaminophen."},{"speaker":"(Charlie) So the answer is A","startTime":293.169,"endTime":297.373,"body":"Or if that wasn't controlling the pain,"},{"speaker":"(Charlie) So the answer is A","startTime":293.169,"endTime":297.373,"body":"then you could also do opioids"},{"speaker":"(Charlie) So the answer is A","startTime":297.374,"endTime":299.262,"body":"or opiate-like medications."},{"speaker":"(Charlie) So the answer is A","startTime":299.263,"endTime":301.509,"body":"(Charlie) With the understanding"},{"speaker":"(Charlie) So the answer is A","startTime":299.263,"endTime":301.509,"body":"that you'd be judicious"},{"speaker":"(Charlie) So the answer is A","startTime":301.51,"endTime":305.538,"body":"similarly in an elderly patient"},{"speaker":"(Charlie) So the answer is A","startTime":301.51,"endTime":305.538,"body":"with chronic underlying comorbidities."},{"speaker":"(Charlie) So the answer is A","startTime":305.539,"endTime":306.61,"body":"(Cathy) Absolutely."},{"speaker":"(Charlie) So the answer is A","startTime":306.611,"endTime":308.213,"body":"(Charlie) Great. Okay, thank you!"},{"speaker":"(Charlie) So the answer is A","startTime":308.214,"endTime":310.665,"body":"[outro music]"}]}