{"version":"1.0.0","segments":[{"startTime":0.377,"endTime":3.24,"body":"[upbeat intro music]"},{"startTime":3.24,"endTime":5.65,"body":"[Dr. Handy] Hi, welcome to Harrison's Podclass,"},{"startTime":5.65,"endTime":8.78,"body":"where we discuss important concepts in internal medicine."},{"startTime":8.78,"endTime":9.846,"body":"I'm Cathy Handy."},{"startTime":9.846,"endTime":11.68,"body":"[Dr. Wiener] And I'm Charlie Wiener, and we're coming to you"},{"startTime":11.68,"endTime":13.78,"body":"from the Johns Hopkins School of Medicine."},{"startTime":15.89,"endTime":17.25,"body":"[Dr. Handy] Welcome to today's episode,"},{"startTime":17.25,"endTime":20.158,"body":"a 67-year-old with a painful right knee."},{"startTime":20.158,"endTime":22.082,"body":"[Dr. Wiener] Hey Cathy, well today's case is"},{"startTime":22.082,"endTime":24.01,"body":"a 67-year-old woman with a history of"},{"startTime":24.01,"endTime":26.07,"body":"right knee replacement four years prior,"},{"startTime":26.07,"endTime":29.181,"body":"who presents with one month of worsening right knee pain"},{"startTime":29.181,"endTime":32.011,"body":"and decreased range of motion in that knee."},{"startTime":32.011,"endTime":35.317,"body":"On examination, she's afebrile but her right knee"},{"startTime":35.317,"endTime":38.608,"body":"is warm and red with some pustules over the top."},{"startTime":38.608,"endTime":42.056,"body":"The redness has a distinct border and surrounds the knee."},{"startTime":42.056,"endTime":45.49,"body":"That knee is tender to direct pressure and movement."},{"startTime":45.49,"endTime":47.36,"body":"The left knee is normal."},{"startTime":47.36,"endTime":49.02,"body":"[Dr. Handy] Okay, so let's stop there for a minute"},{"startTime":49.02,"endTime":50.49,"body":"and talk about what we heard so far."},{"startTime":50.49,"endTime":53.25,"body":"So, it sounds like she has some inflammation of the knee"},{"startTime":53.25,"endTime":54.7,"body":"with warmth and tenderness,"},{"startTime":54.7,"endTime":57.949,"body":"and it's notable that in the knee is a foreign body,"},{"startTime":57.949,"endTime":60.45,"body":"her knee replacement that you mentioned she had."},{"startTime":60.45,"endTime":61.84,"body":"So far, you've only told me about"},{"startTime":61.84,"endTime":63.31,"body":"this one joint being involved,"},{"startTime":63.31,"endTime":65.189,"body":"so I would be thinking of causes"},{"startTime":65.189,"endTime":67.77,"body":"of acute monoarticular arthritis."},{"startTime":67.77,"endTime":70.59,"body":"Now, infection or septic arthritis would be on the list,"},{"startTime":70.59,"endTime":72.988,"body":"but you also need to think about crystalline arthritis and"},{"startTime":72.988,"endTime":75.144,"body":"hemarthrosis, especially in patients"},{"startTime":75.144,"endTime":77.42,"body":"with a prior history of bleeding disorders."},{"startTime":77.42,"endTime":79.453,"body":"Other things to think about would be trauma,"},{"startTime":79.453,"endTime":82.04,"body":"and then less commonly, autoimmune diseases."},{"startTime":82.04,"endTime":83.24,"body":"[Dr. Wiener] You mentioned infection,"},{"startTime":83.24,"endTime":86.096,"body":"I presume you're worried about the prosthetic joint."},{"startTime":86.096,"endTime":88.07,"body":"Wouldn't that be surprising given the time course,"},{"startTime":88.07,"endTime":89.95,"body":"since her surgery was years ago?"},{"startTime":89.95,"endTime":91.67,"body":"[Dr. Handy] So it still could be possible,"},{"startTime":91.67,"endTime":94.33,"body":"her symptoms and examination are consistent with"},{"startTime":94.33,"endTime":97.274,"body":"what we call chronic periprosthetic joint infection."},{"startTime":97.274,"endTime":99.725,"body":"So that's traditionally classified as early"},{"startTime":99.725,"endTime":102.702,"body":"which would be within three months after implementation;"},{"startTime":102.702,"endTime":104.806,"body":"delayed which is between three months"},{"startTime":104.806,"endTime":106.75,"body":"and two years after surgery;"},{"startTime":106.75,"endTime":110.508,"body":"or late which would be over two years after implantation."},{"startTime":110.508,"endTime":112.02,"body":"For therapeutic decision making,"},{"startTime":112.02,"endTime":115.149,"body":"it's more useful to classify periprosthetic joint infection"},{"startTime":115.149,"endTime":118.4,"body":"as either acute hematogenous with fewer than three"},{"startTime":118.4,"endTime":121.933,"body":"weeks of symptoms; early post interventional infections"},{"startTime":121.933,"endTime":124.51,"body":"manifesting within one month after surgery;"},{"startTime":124.51,"endTime":126.81,"body":"or chronic periprosthetic joint infection"},{"startTime":126.81,"endTime":129.74,"body":"with symptoms that last for longer than three weeks."},{"startTime":129.74,"endTime":131.47,"body":"[Dr. Wiener] Okay, so the fact that she's presenting"},{"startTime":131.47,"endTime":133.09,"body":"with about one month of symptoms"},{"startTime":133.09,"endTime":136.233,"body":"four years after her knee replacement is not atypical."},{"startTime":136.233,"endTime":139.645,"body":"What are the typical findings of a chronic infection?"},{"startTime":139.645,"endTime":143.07,"body":"[Dr. Handy] Key findings are joint effusion, local pain,"},{"startTime":143.07,"endTime":146.13,"body":"implant loosening, and occasionally a sinus tract."},{"startTime":146.13,"endTime":148.27,"body":"Now the patient may have generalized fatigue"},{"startTime":148.27,"endTime":150.006,"body":"from the low-grade inflammation."},{"startTime":150.006,"endTime":152.31,"body":"Tell me more about her history and if she has any other"},{"startTime":152.31,"endTime":153.47,"body":"joint problems."},{"startTime":153.47,"endTime":155.57,"body":"[Dr. Wiener] Okay, so as far as past history is,"},{"startTime":155.57,"endTime":157.83,"body":"she was a former competitive skier"},{"startTime":157.83,"endTime":159.799,"body":"and had injured that knee many times through her"},{"startTime":159.799,"endTime":163.355,"body":"twenties and thirties, her knee replacement was for DJD."},{"startTime":163.355,"endTime":165.48,"body":"She's remarkably healthy otherwise."},{"startTime":165.48,"endTime":168.38,"body":"The left knee has some [unintelligible] DJD and is being"},{"startTime":168.38,"endTime":172.095,"body":"followed, but as I mentioned is not acutely inflamed today."},{"startTime":172.095,"endTime":175.368,"body":"Her only medication is atorvastatin for hyperlipidemia."},{"startTime":175.368,"endTime":177.45,"body":"I'll also say that outside of the right knee"},{"startTime":177.45,"endTime":180.006,"body":"her physical examination is totally normal."},{"startTime":180.006,"endTime":183.4,"body":"We did get some labs and her white count is 14.5"},{"startTime":183.4,"endTime":185.0,"body":"with 80% neutrophils."},{"startTime":185.0,"endTime":188.691,"body":"Her C-reactive protein is elevated at 13 mg/L,"},{"startTime":188.691,"endTime":192.358,"body":"and she had a sed rate that's elevated at 50 mm/hour."},{"startTime":192.358,"endTime":195.23,"body":"[Dr. Handy] So she has a neutrophil predominant leukocytosis"},{"startTime":195.23,"endTime":198.133,"body":"with an elevation of her CRP and ESR,"},{"startTime":198.133,"endTime":201.263,"body":"and these values can be seen in chronic joint infections,"},{"startTime":201.263,"endTime":203.397,"body":"although they are relatively sensitive at this level with"},{"startTime":203.397,"endTime":207.26,"body":"a CRP that's at least 10 and an ESR of at least 30,"},{"startTime":207.26,"endTime":209.13,"body":"they're not specific for this."},{"startTime":209.13,"endTime":211.02,"body":"[Dr. Wiener] Okay, well let's get to the question."},{"startTime":211.02,"endTime":211.88,"body":"The question reads,"},{"startTime":211.88,"endTime":213.77,"body":"which of the following should you request?"},{"startTime":213.77,"endTime":218.572,"body":"And the options are A. initiate IV vancomycin;"},{"startTime":218.572,"endTime":221.33,"body":"B. a joint aspiration;"},{"startTime":221.33,"endTime":224.14,"body":"C. a surgical consultation;"},{"startTime":224.14,"endTime":226.64,"body":"and then option D says, you can get A and C,"},{"startTime":226.64,"endTime":229.835,"body":"which would be vancomycin and a surgical consultation;"},{"startTime":229.835,"endTime":232.19,"body":"or option E says, you can get B and C,"},{"startTime":232.19,"endTime":235.64,"body":"which is joint aspiration and a surgical consultation."},{"startTime":235.64,"endTime":237.987,"body":"[Dr. Handy] Well, what I would do is definitely"},{"startTime":237.987,"endTime":240.93,"body":"joint aspiration, but then also surgical consultation,"},{"startTime":240.93,"endTime":243.419,"body":"so that would be option choice E."},{"startTime":243.419,"endTime":246.01,"body":"Now an important distinction is that she does not appear"},{"startTime":246.01,"endTime":249.86,"body":"septic, so in this case empiric antibiotics are not warranted."},{"startTime":249.86,"endTime":252.327,"body":"Antibiotics should be deferred until joint aspiration or"},{"startTime":252.327,"endTime":254.97,"body":"surgical sampling can be performed."},{"startTime":254.97,"endTime":257.715,"body":"Now, treatment of prosthetic joint infection requires"},{"startTime":257.715,"endTime":260.577,"body":"a multidisciplinary approach, including an orthopedic surgeon"},{"startTime":260.577,"endTime":262.51,"body":"and an infectious disease specialist,"},{"startTime":262.51,"endTime":265.297,"body":"so most patients are referred to a specialized center."},{"startTime":265.297,"endTime":267.576,"body":"In general, the goal of treatment is cure,"},{"startTime":267.576,"endTime":270.414,"body":"so that means a pain-free, functional joint with complete"},{"startTime":270.414,"endTime":273.555,"body":"eradication of the infecting pathogens."},{"startTime":273.555,"endTime":276.849,"body":"As a rule, antimicrobial therapy without surgical intervention"},{"startTime":276.849,"endTime":279.6,"body":"is not curative but merely suppressive."},{"startTime":279.6,"endTime":281.71,"body":"There are four curative surgical options."},{"startTime":281.71,"endTime":284.404,"body":"So either debridement and implant retention,"},{"startTime":284.404,"endTime":288.29,"body":"a one-stage implant exchange, a two-stage implant exchange,"},{"startTime":288.29,"endTime":290.9,"body":"or an implant removal without replacement."},{"startTime":290.9,"endTime":292.77,"body":"[Dr. Wiener] What are the common causative organisms"},{"startTime":292.77,"endTime":295.43,"body":"in chronic prosthetic joint infections?"},{"startTime":295.43,"endTime":296.6,"body":"[Dr. Handy] It's most commonly caused by"},{"startTime":296.6,"endTime":298.05,"body":"low-virulence organisms,"},{"startTime":298.05,"endTime":301.78,"body":"such as coagulase-negative staphylococci or P. acnes."},{"startTime":301.78,"endTime":304.38,"body":"The more acute forms are typically due to the more virulent"},{"startTime":304.38,"endTime":306.383,"body":"bacteria such as Staph aureus."},{"startTime":306.383,"endTime":308.419,"body":"[Dr. Wiener] Okay, great. So the teaching points"},{"startTime":308.419,"endTime":310.86,"body":"in this case are that prosthetic joint infections"},{"startTime":310.86,"endTime":313.317,"body":"should be characterized by their timeframe."},{"startTime":313.317,"endTime":316.59,"body":"Chronic infections may happen even years after surgery and"},{"startTime":316.59,"endTime":319.35,"body":"usually present with low grade systemic inflammation and"},{"startTime":319.35,"endTime":322.024,"body":"findings that are local to the prosthesis."},{"startTime":322.024,"endTime":325.092,"body":"Appropriate therapy is multidisciplinary and empiric"},{"startTime":325.092,"endTime":328.14,"body":"antibiotics are not necessary in a non-acutely ill,"},{"startTime":328.14,"endTime":329.96,"body":"non-septic patient."},{"startTime":329.96,"endTime":331.33,"body":"[Dr. Handy] And you can read more about this"},{"startTime":331.33,"endTime":334.42,"body":"in Harrison's chapter on infections of prosthetic joints."},{"startTime":334.42,"endTime":336.53,"body":"[Dr. Wiener] I'm glad to know there's a full chapter on that."},{"startTime":336.53,"endTime":337.785,"body":"[Dr. Handy chuckles]"},{"startTime":337.785,"endTime":341.752,"body":"[outro music]"},{"startTime":341.752,"endTime":344.607,"body":"[Mr. Shanahan] This is Jim Shanahan, publisher at McGraw Hill."},{"startTime":344.607,"endTime":346.357,"body":"Harrison's Podclass is brought to you by"},{"startTime":346.357,"endTime":348.2,"body":"McGraw Hill's Access Medicine,"},{"startTime":348.2,"endTime":351.085,"body":"the online medical resource that delivers the latest trusted"},{"startTime":351.085,"endTime":353.504,"body":"content from the best minds in medicine."},{"startTime":353.504,"endTime":356.4,"body":"Go to accessmedicine.com to learn more."}]}