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Differential Diagnosis Diagnostic Process? 8/23/2010 What We’ll Cover Today • 1. (Part 1) Differential Diagnosis (defined) The Best Tests for Diagnosis: And Why – The decision making process it's Important – Costs associated with errors in decision making • 3. (Part 2) Diagnostic Accuracy – The language of diagnosis Chad Cook PT, PhD, MBA, OCS, FAAOMPT – Bias (studying diagnosis) Professor and Chair Walsh University • 4. (Part 3) Best tests for diagnosis (Part 1) Differential Diagnosis My Objectives • Differential diagnosis is a systematic 1. Differential Diagnosis is Extremely Important process used to identify the proper (in the early phases of the examination but diagnosis from a competing set of possible less so in the later phases of the examination) diagnoses. 2. Recognizing Bias in Diagnosis is Half the Battle • Diagnosis is one of many necessary 3. It is Critical to Know which tests are best used components during the clinical decision early or late in the examination making process Diagnostic Process? Who Performs Diagnoses? • The Diagnostic process involves identifying or • Anyone who treats determining the etiology of a disease or patients condition through evaluation of patient • Certainly, physical history, physical examination, and review of therapists laboratory data or diagnostic imaging; and the subsequent descriptive title of that finding Whiting et al. J Health Serv Res 2008 1 8/23/2010 PT’s and Diagnosis 1988 Why it’s Important • “Physical Therapists thus must establish • Failure to correctly identify an appropriate diagnostic categories that direct their diagnosis can lead to: treatment prescriptions and that provide a – Negative outcomes (Trowbridge 2008). means of communication both within the – Delays in appropriate treatment (Whiting et al. profession and with other practitioners and 2008) consumers about the conditions that require – Unnecessary healthcare costs (Dohrenend and their particular expertise for effective Skillings) treatment and prognostication” Sahrmann S. Diagnosis by the physical therapist: A prerequisite for treatment. Phys Ther. 1988;68:1703-6. Can Lead to Death Most Common Types and Locations? • 44,000 to 98,000 • Most in physician offices Americans die (primary care 31%, annually as a medical specialty 21%) result of medical • Error types: Diagnostic 36%, surgical 24%, non- errors (1999). surgical procedures 14%, medications 13% Institute of Medicine. To err is human: building a safer health system. Kohn, Corrigan, Woods DM, Thomas EJ, Holl J. Ambulatory care adverse events and preventable adverse events and Donaldson (ed). Washington DC. National Academies Press, 1999, leading to hospital admission. Qual Saf Health Care 2007;16;127-131 ED Missed Diagnoses Worth Noting • Leading breakdowns • Delayed Diagnosis – Failure to order 58% – Diagnosis is made but – Inadequate at a later date history/physical 42% – Incorrect test • Misdiagnosis interpretation 37% – Diagnosis is missed Kachalia A, Gandhi TK, Puopolo AL, et al. Missed and delayed diagnoses in the ambulatory setting: Both cause adverse events a study of closed malpractice claims. Ann Intern Med. 2006;145:488-96. 2 8/23/2010 Diagnosis vs. Treatment Difficult, but Preventable • Acting on Insufficient Information* – (81% High Preventability) • Misapplication of, or failure to apply a rule or use a bad or inadequate rule – (90.3% High • 34.8% resulted in permanent disability • 86.5% of diagnostic delays were highly preventable Preventability) Wilson R, Harrison B, Gibberd R, et al. An analysis of the causes of adverse events from the Quality in Australian Health Care Study. MJA 1999; 170: 411-415 Wilson R, Harrison B, Gibberd R, et al. An analysis of the causes of adverse events from the Quality in Australian Health Care Study. MJA 1999; 170: 411-415 Costs associated with Too Many Lab Healthcare Costs Tests and Imaging • 50 to 53 million US dollars per million members, per year for a Referral• “Incorrect for lumbar diagnoses spine may medical misdiagnosis. radiographylead to incorrect for first and presentation of lowineffective back pain treatment in primary or care • 6.1 to 10.4 billion dollars is notunnecessary associated testing, with improved which is (adjusted) annually (for diagnostic physicalcostly functioning, and sometimes pain errors) or disability.invasive” Medical Misdiagnosis: Overlooked opportunity for meaningful health plan improvement Kerry et al. Br J Gen Pract. 2002;52:469-74. of quality and costs. Managed Care Outlook. 2008;21(8). Reducing Errors in Health Care: Translating Research Into Practice . AHRQ Publication No. 00-PO58, April 2000. Agency for Healthcare Research and Quality, Rockville, MD. Institute of Medicine. To err is human: building a safer health system. Kohn, Corrigan, http://www.ahrq.gov/qual/errors.htm and Donaldson (ed). Washington DC. National Academies Press, 1999, Cost Utility Analysis Old Knowledge • An interdisciplinary early intervention • Seeing a rehab specialists treatment model was the preferred option in results in fewer loss of work over 85% of the samples within the an days per dedicated injury (whether serious or not established range of acceptable costs. serious) (N=2700) • (most of these interventions are underutilized because of physician concerns of cost and applicability) • Rogerson, Gatchel, & Bierner. Pain Pract. 2010;Apr 5. E-pub, ahead of print. Haig et al. Aggressive early medical management by a specialist in physical medicine and rehabilitation: effect on lost time due to injuries in hospital employees. J Occup Med. 1990;32:241-4. 3 8/23/2010 Misdiagnosis: A System Problem? Only Physicians? • < 5% of Primary Care Physicians Routinely Examine for Red Flags during an Initial Screen • Bishop & Wing. Spine J. 2006: 6:282-8. • “Low rates of compliance for the assessment and documentation of yellow and red flags” • Walsh et al. Occup Med. 2008;58:485-9. Orthopedic Surgeons? I’m Immune to your consultations (Bowie D) • “Both orthopedic surgeons and family physicians’ • …Not in my setting knowledge of treating LBP is deficient.” • ….I’ve never been in a direct • “Orthopedic surgeons are less aware of current access environment treatment than family practitioners” • …..I work with good • Finestone et al. Spine. 2009;34:1600-3. physicians • ……The prevalence is so low….. • …. I don’t see patients with those diagnoses .. Missed cancer diagnoses Most Commonly Missed Diagnoses? Kachalia A, Gandhi TK, Puopolo AL, et al. Missed and delayed diagnoses in the ambulatory setting: a study of closed malpractice claims. Ann Intern Med. 2006;145:488-96. 4 8/23/2010 What’s the Best Way to Go About the Diagnosis is Part of a Process “Process” • It is most important when the condition at hand is • A couple of thoughts unknown or a competing – Use a dedicated strategy – Understand the metrics of certain diagnosis is as likely as the findings presumed condition – Never rely too heavily on a single measure – Realize that diagnosis is a “process” not an “event” Tekwani K, Sikka R. High Risk Chief Complaints III: Abdomen and Extremities. Emerg Med Clin N Am. 2009;27:747-65. The Process Three Diagnostic Questions when Addressing a Patient Rule Out Sinister Problems • The first question of diagnosis: Are the patient's symptoms reflective of a visceral disorder or a serious or potentially life-threatening illness? • The second question of diagnosis: From where is Identify the the patient's pain arising? Appropriate Location • The third question of diagnosis: What has gone wrong with this person as a whole that would cause the pain experience to develop and persist? Identify “other” Contributors to the Condition Murphy D, Hurwitz E. A theoretical model for the development of a Murphy D, Hurwitz E. A theoretical model for the development of a diagnosis- diagnosis-based clinical decision rule for the management of patients with based clinical decision rule for the management of patients with spinal pain. BMC spinal pain. BMC Musculoskeletal Disorders 2007, 8:75 Musculoskeletal Disorders 2007, 8:75 Early Stages of Diagnosis • Specific to the necessity for accuracy, is the ability to differentiate patients with symptoms that arise from non-mechanical disorders or other potentially life threatening pathology • Tests will require high levels of sensitivity, low LR-, and reasonable reliability Murphy D, Hurwitz E. A theoretical model for the development of a diagnosis- based clinical decision rule for the management of patients with spinal pain. BMC Musculoskeletal Disorders 2007, 8:75 Rubinstein SD, van Tulder M. A best-evidence review of diagnostic procedures for neck And low back pain. Best Practice & Research Clinical Rheum. 2008;22:471-482. 5 8/23/2010 Example Some Foreshadowing • Mr. Smith, who was seen through direct access complained of an aching pain in his left lateral thigh. • “The findings of our study suggest that the The pain was worse at night and was described as a deep, boring, ache. majority of clinical tests for the spine with The comprehensive clinical acceptable diagnostic accuracy are for non- examination yielded no mechanical critical diagnoses.” findings during provocation or reduction testing and no special test that implicated a specific finding. Palpation findings were also inconclusive. Cook C, Hegedus E. Diagnostic utility of clinical tests for spinal dysfunction. Man Ther. 2010. (accepted for publication) Part Two of the Process Ruling Out Location? • The second question of diagnosis: • Using tests with high sensitivity (or From where is the patient's pain overpressures) to rule out a body part region arising? as
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