In medicine, differential diagnosis (sometimes abbreviated DDx or ΔΔ) is the systematic method physicians use to identify the disease causing a patient's symptoms.
Before a medical condition can be treated, it must be identified. In the process of listening to a patient's complaints, examining the patient, and taking the patient's personal, family and social history, the physician makes a mental list of the most likely causes. The doctor asks additional questions and performs tests to eliminate possibilities until he or she is satisfied that the single most likely cause has been identified.
Once a working diagnosis is reached, the physician prescribes a therapy. If the patient's condition does not improve, the diagnosis must be reassessed. The method of differential diagnosis was first suggested for use in the diagnosis of mental disorders by Emil Kraepelin. It is more systematic than the old-fashioned method of diagnosis by gestalt (impression).
The term differential diagnosis also refers to medical information specially organized to aid in diagnosis, particularly a list of the most common causes of a given symptom, annotated with advice on how to narrow down the list.
There are various methods of clinical reasoning include probabilistic (Bayesian), causal (physiologic), and deterministic (rule-based).[1] In addition, medical experts rely more on pattern recognition which is faster[2]; however, clinical experts seem flexible and may use whichever method of reasoning most easily represents and solves a given problem.[3] When confronted with non-challenging cases physicians may use 'nonanalytical reasoning' such as pattern recognition; however, during more difficult cases physicians may switch to 'reflective reasoning'.[4] Reflective reasoning may especially help complex cases.[5] Explicit Bayesian thinking with precise numbers is rarely done.[6][7] Basic science knowledge is probably "encapsulated" into clinical knowledge.[8]
Possible strategies to improve clinical reasoning have been reviewed[9][10] and using problem-based learning[10], include teaching appropriate problem representation creating a one-sentence summary of a case[9], standardized patients[11], teaching hypothetico-deductive reasoning[12][13], cognitive forcing strategies[14][15][16] to avoid premature closure[17], teaching the competing-hypotheses heuristic[18], using fuzzy-trace theory[19] and mixed-methods interventions[20][21][20]. Studies are unclear about teaching logic.[22][23]
Scales to measure clinical reasoning have been proposed.[24]
Regarding hypothetico-deductive reasoning, an observational study on the methods used by experts solving clinicopathological exercises reported that these experts use the following six steps:[13]
Successfully distilling complex information into a short summary, perhaps using semantic qualifiers, may help diagnostic accuracy.[29][30][31][32] Problem representation, "usually as a one-sentence summary defining the specific case in abstract terms," may help clinical reasoning[9][30][33].
Various methods have been proposed for improving quantitative literacy. For diagnosis, likelihood ratios[34] or sensitivity and specificity are two methods. It is unclear which method is better according to the results of a controlled trial.[35]
Studies are inconclusive on using cognitive feedback.[36].
Framing bias is best avoided by using numeracy with absolute measures of efficacy.[37]
↑Leape LL (1994). "Error in medicine". JAMA. 272: 1851–7. PMID7503827.
↑Norman G (2006). "Building on experience--the development of clinical reasoning". N Engl J Med. 355: 2251–2. doi:10.1056/NEJMe068134. PMID17124025.
↑Mamede S, et al. (2008) Influence of Perceived Difficulty of Cases on Physicians' Diagnostic Reasoning. Academic Medicine. 83(12):1210-1216. doi:10.1097/ACM.0b013e31818c71d7
↑Moskowitz AJ; et al. (1988). "Dealing with uncertainty, risks, and tradeoffs in clinical decisions. A cognitive science approach". Ann. Intern. Med. 108: 435–49. PMID3277516.CS1 maint: Explicit use of et al. (link)
↑Reid MC, Lane DA, Feinstein AR (1998). "Academic calculations versus clinical judgments: practicing physicians' use of quantitative measures of test accuracy". Am J Med. 104: 374–80. PMID9576412.CS1 maint: Multiple names: authors list (link)
↑de Bruin AB; et al. (2005). "The role of basic science knowledge and clinical knowledge in diagnostic reasoning: a structural equation modeling approach". Academic Medicine. 80: 765–73. PMID16043534.CS1 maint: Explicit use of et al. (link)
↑ 10.010.1Graber M; et al. (2002). "Reducing diagnostic errors in medicine: what's the goal?". Academic Medicine. 77: 981–92. PMID12377672.CS1 maint: Explicit use of et al. (link)
↑Windish DM; et al. (2005). "Teaching medical students the important connection between communication and clinical reasoning". J Gen Intern Med. 20: 1108–13. doi:10.1111/j.1525-1497.2005.0244.x. PMID16423099.CS1 maint: Explicit use of et al. (link)
↑Wiese J; et al. (2002). "Improving oral presentation skills with a clinical reasoning curriculum: a prospective controlled study". Am J Med. 112: 212–8. PMID11893348.CS1 maint: Explicit use of et al. (link)
↑ 13.013.1Eddy DM, Clanton CH (1982). "The art of diagnosis: solving the clinicopathological exercise". N Engl J Med. 306: 1263–8. PMID7070446.
↑Croskerry P (2000). "The cognitive imperative: thinking about how we think". Academic Emergency Medicine. 7: 1223–31. PMID11073470.
↑Croskerry P (2002). "Achieving quality in clinical decision making: cognitive strategies and detection of bias". Academic Emergency Medicine. 9: 1184–204. PMID12414468.
↑Dubeau CE; et al. (1986). "Premature conclusions in the diagnosis of iron-deficiency anemia: cause and effect". Medical Decision Making. 6: 169–73. PMID3736379.CS1 maint: Explicit use of et al. (link)
↑ 18.018.1Wolf FM; et al. (1988). "Use of the competing-hypotheses heuristic to reduce 'pseudodiagnosticity'". J Med Educ. 63: 548–54. PMID3385753.CS1 maint: Explicit use of et al. (link)
↑Lloyd FJ, Reyna VF (2001). "A web exercise in evidence-based medicine using cognitive theory". J Gen Intern Med. 16: 94–9. PMID11251760. PubMed Central
↑ 20.020.1Windish DM (2000). "Teaching medical students clinical reasoning skills". Acad Med. 75 (1): 90. PMID10667884.
↑Struyf E, Beullens J, Van Damme B, Janssen P, Jaspaert H (2005). "A new methodology for teaching clinical reasoning skills: problem solving clinical seminars". Med Teach. 27 (4): 364–8. doi:10.1080/01421590500046411. PMID16024422.CS1 maint: Multiple names: authors list (link)
↑Cheng PW; et al. (1986). "Pragmatic versus syntactic approaches to training deductive reasoning". Cognitive Psychology. 18: 293–328. doi:10.1016/0010-0285(86)90002-2. PMID3742999.CS1 maint: Explicit use of et al. (link)
↑Jenicek M (2006). "The hard art of soft science: Evidence-Based Medicine, Reasoned Medicine or both?". Journal of Evaluation in Clinical Practice. 12: 410–9. doi:10.1111/j.1365-2753.2006.00718.x. PMID16907682.
↑Boshuizen HP; et al. (1997). "Measuring knowledge and clinical reasoning skills in a problem-based curriculum". Medical education. 31: 115–21. PMID9231115.CS1 maint: Explicit use of et al. (link)
↑Richardson WS, Wilson MC, Keitz SA, Wyer PC (2007). "Tips for Teachers of Evidence-based Medicine: Making Sense of Diagnostic Test Results Using Likelihood Ratios". J Gen Intern Med. doi:10.1007/s11606-007-0330-1. PMID18064524.CS1 maint: Multiple names: authors list (link)
↑Poses RM; et al. (1995). "You can lead a horse to water--improving physicians' knowledge of probabilities may not affect their decisions". Medical Decision Making. 15: 65–75. PMID7898300.CS1 maint: Explicit use of et al. (link)
↑Perneger TV, Agoritsas T (2011). "Doctors and Patients' Susceptibility to Framing Bias: A Randomized Trial". J Gen Intern Med. doi:10.1007/s11606-011-1810-x. PMID21792695.