Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Differential Diagnosis Generation


Published on

"How I learned to stop worrying and love the BALM:" a method to developing a differential diagnosis

Published in: Health & Medicine
  • Be the first to comment

Differential Diagnosis Generation

  1. 1. Differential Diagnosis<br />Or “How I learned to stop worrying and love the BALM”<br />Clinton Pong<br />
  2. 2. Objectives<br />Define “differential diagnosis”<br />Errors<br />aka how do you get the “right ddx”<br />Develop a systematic, routine method for differential diagnosis generation<br />The BALM<br />
  3. 3. The Challenge: What is a Ddx?<br />Recognize a collection of signs and symptoms<br />Recall basic pathophysiology<br />Restate in terms of disease<br />Reconnect with the initial complaint<br />Framing: pre-/post-test probability<br />Reframing: Reconsidering ddx when there is a progression of unusual natural history<br />
  4. 4. How many times have you done this?<br />Premature closure of diagnosis<br />“Hm, this is the cardio unit and they have chest pain. Duh. It’s a heart attack.”<br />The crazy “House” diagnosis<br />“Chest pain and shortness of breath?!? They could have a worm like Strongyloidesstercoralis that went up their gut into their lungs and then to their bloodstream!”<br />The LI of the MINDNUMBING table of differentials A-Z + 1,2,3,4,5,6,7,8,9,10…<br />
  5. 5. Cognitive Diagnostic Errors<br />Examples:<br />“Umm… trauma or cancer?”<br />“80 years old? I thought you said 18 years old.”<br />“Psh. It’s just a little ____.”<br />“The ___ is (+) so it is ____.”<br />“The __ is (-) so it is not __.”<br />“It’s gotta be a ____.”<br />Errors<br />Faulty hypothesis generation<br />Faulty context formulation<br />Faulty information gathering/processing<br />Inaccurate assessment of prevalence or severity<br />Wrong interpretation of test<br />Overrreliance on clinical axiom<br />Faulty verification<br />Premature closure of diagnosis<br />“No-fault” errors<br />
  6. 6. Many diagnostic errors occur because we try<br /> to fit the data to our hypothesis rather than<br /> fitting the hypothesis to our data.<br /><br />
  7. 7.<br /><br />
  8. 8. House, MD. White board<br /><br />
  9. 9. Occam’s Razor:Quest for the Holy Parsimony<br />“Plurality should not be posited without necessity.”<br />Pluralitas non estponenda sine necessitate<br /><br />
  10. 10. Sherlock Holmes<br />&quot;When you have eliminated the impossible, whatever remains, however improbable, must be the truth.&quot;<br />
  11. 11. DeGowin’s Quotable:<br />Disease is a four-dimensional story, which follows the biologic imperatives of its particular pathophysiology in specific anatomic sites as influenced by the unique characteristics of this patient.<br />Your task is not verbal, but cinematic; construct a pathophysiologic and anatomic movie of the onset and progression of the illness: the words are generated from the images, not the images from the words. <br />
  12. 12. Nobody ever needs to know that the instant you see lawyer [on the USMLE] you immediately think:<br /> “Scumbag who sleeps with prostitutes and therefore has gonorrhea, syphilis, chlamydia, and herpes.”<br />It’ll stay our dirty little secret.<br /><br />
  13. 13. Race/Ethnicity<br />African Americans have sarcoid and sickle cell.White kids have cystic fibrosis and can’t dance.Japanese people have stomach cancer and ninja skills.<br />Lifestyles<br />Women are always pregnant. No matter how careful they were.Coke Addicts had an MI (don’t smoke crack, kids!)Patients with a swollen knee are female, young, hot, and caught gonorrhea from their last boyfriend.<br />Etc…<br /><br />
  14. 14. The BALM<br />By systems<br />Acute vs Chronic<br />Local vs Systemic<br />MEDICINE DOC<br />Great tier system for starting off your ddx<br />Where is it?<br />Will it kill the patient?<br />What else can it do?<br />If all else fails, go to the laundry list.<br />
  15. 15. Framework<br />AcutevsChronic<br />LocalvsSystemic<br />High Probability – Incidence<br />(the most difficult part of the frame as a medical student)<br />What is most likely? Rare  Common<br />High Utility – Morbidity/Mortality<br />What do you want to make sure you never miss? Benign  Serious<br />
  16. 16. The Systems Approach<br />MEDICINE<br />Metabolic/Medications<br />Endocrine<br />Degenerative<br />Infection/Ischemia/Infarction<br />Congenital<br />Iatrogenic/Idiopathic<br />Neoplastic<br />Electrical (Neuro/Psych)<br />Alternatively,<br /><ul><li>I VINDICATE AID
  17. 17. DIRECTION
  18. 18. VITAMIN C,D</li></ul>PE organ systems list<br />Neuro<br />Lung<br />CV<br />GI<br />Renal/GU/GYN<br />Heme/ID<br />Endo<br />
  19. 19. The Systems Approach<br />VITAMIN C, D & E<br />Vascular<br />Infection/Ischemia/Infarction<br />Trauma/Toxin<br />Autoimmune<br />Metabolic/Medications<br />Iatrogenic/Idiopathic<br />Neoplastic<br />Congenital<br />Degenerative<br />Electrical (Neuro/Psych)<br />Alternatively,<br /><ul><li>I VINDICATE AID
  20. 20. DIRECTION
  21. 21. MEDICINE</li></ul>PE organ systems list<br />Neuro<br />Lung<br />CV<br />GI<br />Renal/GU/GYN<br />Heme/ID<br />Endo<br />
  22. 22. By discipline<br />Hint hint…<br />
  23. 23. Resources<br />Groopman, Jerome. How Doctors Think. Mariner Books © 2008.<br />Kassirer, Jerome. Learning Clinical Reasoning. Williams and Wilkins. © 1991.<br />DeGowin&apos;s Diagnostic Examination, Ninth Edition (Paperback) by Richard LeBlond (Author), Donald Brown (Author), Richard DeGowin (Author)<br /><br />(Heuristics) Bigot your way to Success on the USMLE<br /><br />“Separating clinicians from automatons: the long tail”<br /><br />