Chapter 1: Overview

Introduction Clinical reasoning is the essential function of the physician; optimal patient care depends on keen diagnostic acumen and thoughtful analysis of the tradeoffs between the benefits and risks of tests and treatments. As benchmarks for considering these issues, here are several real examples: A 33-year-old man presents to the emergency room complaining of headache, […]

Chapter 2: Diagnostic Hypothesis Generation

Hypotheses and Cues ( Case 1, Case 2 , Case 3– Case 4, Case 16) In our daily life, we are constantly generating hypotheses about our environment—about our visual images, how the physical world operates, our expectations of events, and our perceptions of people. These hypotheses provide a framework for interpreting all of our unstructured […]

Chapter 3: Refinement of Diagnostic Hypotheses

Where Refinement Begins and Ends ( Case 1, Case 12 , Case 13, Case 16, Case 17, Case 37, Case 38) After hypotheses are evoked, the process of hypothesis refinement, also known as “case building,” ensues. Hypothesis refinement is an evolving, sequential process of data gathering and interpretation. Repeated inferences yield a series of provisional […]

Chapter 4: Use and Interpretation of Diagnostic Tests

The Function of Tests Diagnostic testing is an information-gathering task that differs from the processes discussed in the previous chapter only in respect to the risks and costs that tests incur. Testing is used in the process of hypothesis refinement to help formulate a working diagnostic hypothesis, defined previously as one that is sufficiently unambiguous […]

Chapter 5: Causal Reasoning

Definition ( Case 32 , Case 34, Case 35) The process of arriving at a working diagnosis requires interpretation of new data in light of existing information and assessment of the relations among all of the clinical findings. In carrying out these tasks, the physician makes repeated attempts to “tie all the findings together.” The […]

Chapter 6: Diagnostic Verification

Definition ( Case 37, Case 38– Case 39, Case 56) Before a diagnosis is accepted as a basis for action, namely prognostication or therapy (i.e., a working diagnosis), it must be subjected to a detailed validity assessment. The processes used in this assessment are described here as diagnostic verification. This process makes a final check […]

Chapter 7: Therapeutic Decision Making

Principles We make every effort to select a treatment according to scientific principles. We try to avoid anecdotal reports of therapeutic efficacy and risk because factors such as placebo effect and individual variation in reactions to treatment can cloud the interpretation of individual responses. To avert these confounding variables, we rely heavily on randomized, controlled […]

Chapter 8: Examining Evidence

Introduction The preceding chapters considered the processes by which diagnoses are made and described approaches to understanding the tradeoffs between the risks and benefits of tests and treatments. However, process is never sufficient to deal with clinical medicine, even the simplest cases. There is no substitute for marrying effective clinical decision making with hard facts […]

Chapter 9: Cognitive Errors

Scope Unfortunately, errors in diagnosis and treatment selection are common occurrences in medicine, and in 2000, the Institute of Medicine estimated that nearly 100,000 deaths yearly could be attributed to some kind of error.[ 73] Errors can range from as important an error as removing a normal kidney instead of a diseased one to as […]

Chapter 10: Some Cognitive Concepts

Cognitive Science ( Case 65) Cognition—the process of perceiving and knowing—underlies all of human problem solving and decision making. In recent years, attempts by scientists in several fields to understand cognitive processes have converged within the discipline of cognitive science. Cognitive science views the mind as an information processor that receives, transforms, retrieves, and transmits […]