1 / 19

Diagnosing Diagnostic Mistakes: Insights from a 2005 Case Study

This educational presentation, based on a May 2005 AHRQ WebM&M Spotlight Case, explores the complexities of diagnostic errors in clinical practice. It highlights the challenges of overcalling mistakes due to biases such as hindsight and the absence of gold standards in diagnosis. The case of a radiologist misinterpreting his own chest X-ray underscores the implications of considering competing diagnoses and the variability in clinical presentations. Participants will gain a better understanding of how bias can affect diagnosis and patient outcomes.

dory
Télécharger la présentation

Diagnosing Diagnostic Mistakes: Insights from a 2005 Case Study

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spotlight Case May 2005 Diagnosing Diagnostic Mistakes

  2. Source and Credits • This presentation is based on the May 2005 AHRQ WebM&M Spotlight Case • See the full article at http://webmm.ahrq.gov • CME credit is available through the Web site • Commentary by: Robert McNutt, MD; Richard Abrams, MD; Scott Hasler, MD • Editor, AHRQ WebM&M: Robert Wachter, MD • Spotlight Editor: Tracy Minichiello, MD • Managing Editor: Erin Hartman, MS

  3. Objectives At the conclusion of this educational activity, participants should be able to: • Understand the biases that may contribute to overcalling medical errors • Describe the impact of considering the clinical spectrum of disease presentations or alternative diagnoses on assessment of error • Appreciate the challenges inherent in assigning the label of “missed diagnosis” to a clinical scenario

  4. “Overdiagnosis” of Diagnostic Mistakes • Knowledge base in safety research cannot provide definitive correlations between decisions, systems of delivery, and adverse events • Error identification schemes find error due to simple chains of events • Given complexities, redundancy and codependency are more likely • True cause and effect difficult to demonstrate McNutt RA, Abrams RI. Qual Manag Health Care. 2002;10:23-28.

  5. Sources of Overcalling Error • Evaluation of a case with knowledge of the patient’s outcome (hindsight bias) • Lack of a gold standard • Failure to consider the spectrum of clinical presentations • Failure to consider the consequences of competing diagnoses

  6. Case: “Doctor Don’t Treat Thyself” • A 50-year-old radiologist presented with shortness of breath and interpreted his own chest x-ray as being “consistent” with the diagnosis of pneumonia. Later the patient dies of a myocardial infarction and pulmonary edema. Several radiologists reviewed the chest x-ray (after the outcome) and reported it “consistent” with pulmonary edema.

  7. WebM&M Case Analysis • The case is considered to “dramatically and tragically” illustrate a diagnostic mistake based on the assessment of radiologists who interpreted the studies after the outcome of the case was known.

  8. Failure to Consider Hindsight Bias • Patient classified as low risk for adverse outcomes (0.1%-0.4% mortality) • No definitive guidelines for screening CXR in patients with a low risk score • Performance characteristics of CXR not known • Outcome of patient should not be known prior to defining diagnostic error Carthey J. Qual Saf Health Care. 2003;12(suppl 2):ii13-16.Lilford RJ, et al. Qual Saf Health Care. 2003;12(suppl 2):ii8-12.

  9. Lack of a Gold Standard • Diagnostic errors difficult to call when there is no gold standard for diagnosis • Without gold standard, all diagnoses probabilistic and certainty impossible • Variation in clinical evaluation of dyspnea well established • Only “fair to good” correlation between radiographic interpretation of CXR findings of pneumonia Mulrow, et al. J Gen Intern Med. 1993;8:383-392. Badgett, et al. JAMA. 1997;277:1712-1719. Albaum, et al. Chest. 1996;110:343-350.

  10. Case: “Crushing Chest Pain” • A 62-year-old woman is admitted with crushing chest pain and treated for possible myocardial infarction. She later dies of an aortic dissection and the case is presented as a diagnostic error.

  11. WebM&M Case Analysis • Initial diagnosis of acute coronary syndrome reasonable due to lower base rates of competing diagnoses • “Most critical error in the case” was misinterpretation of the CXR, which revealed the tell-tale “calcium sign”

  12. Calcium Sign Magnified in Radiograph

  13. Failure to Consider Spectrum of Clinical Presentations • Clinical presentations of disease vary • Some noted by casual observations of widened mediastinum, while others can be missed even after utmost scrutiny • CXR findings not reliable • Diagnostic “calcium sign” very subtle in this case and required magnification • Quality of literature assessing performance of diagnostic tests for aortic dissection is poor Klompas M. JAMA. 2002;287:2262-2272.Moore AG, et al. Am J Cardiol. 2002;89:1235-1238.

  14. Failure to Consider Consequences of Competing Diagnoses • Several serious diseases may explain the patient’s complaint • Empiric treatment of one increases the chance of death in another • Value of diagnostic tests to differentiate one disease from another is unknown or poorly studied

  15. Failure to Consider Consequences of Competing Diagnoses • Differential diagnosis in this case includes myocardial infarction, acute coronary syndrome (ACS), pulmonary embolus, and aortic dissection (AD) • Work up for AD may delay life saving anticoagulant therapy for ACS • ACS is more likely, more harm than good may come from an overzealous attempt to not miss AD

  16. Threshold Model of Decision Making • Ratio of AD to ACS is 1:250 • If AD diagnosed without delay, save a life; while delay in ACS diagnosis increases death or MI by 1% • A delay in treating ACS would kill or harm 2.5 patients with ACS while saving 1 with AD • This sort of trade-off for certainty of diagnosis is not warranted Meszaros, et al. Chest. 2000;117:1271-1278. Husted, et al. J Intern Med. 1989;226:303-310. Pauker, Kassirer. N Engl J Med. 1980;302:1109-1117.

  17. Improving Diagnosis of Errors • Case evaluation should occur without knowledge of case outcome • Evaluation should be done by an independent review panel following structured format using evidence based guidelines • Classification systems for diagnosis error must incorporate methods to evaluate spectrum of illness issues Lilford RJ, et al. Qual Saf Health Care. 2003;12(suppl 2):ii8-12.

  18. Improving Diagnosis of Errors • Use the threshold model of decision making • Consider explicit tradeoffs before asserting error has occurred Pauker SG, Kassirer JP. N Engl J Med. 1980;302:1109-1117.

  19. Take-Home Points • When determining whether an adverse outcome represents a preventable “missed diagnosis,” ask the following questions: • Are the diagnosticians seeking a reasonable differential diagnosis? • Do diagnostic plans incorporate the risk/benefit of finding one diagnosis rather than another? • Were the appropriate tests ordered for the differential diagnosis list?

More Related