Adequacy: Diagnostic sufficiency. An adequate diagnostic hypothesis is one that encompasses all elementary hypotheses under consideration and accounts for all of the patient’s findings, whether abnormal or normal. Ambiguity: The degree of uncertainty in a probability assessment. The degree of confidence in a probability assessment. A second-order probability; the probability of a probability. Anchoring heuristic; […]

Chapter 22: Learning Clinical Problem Solving

Case 67. Learning Clinical Reasoning from Examples A 48-year-old man presented with a 2-day history of headaches and neck stiffness. He also had a mild sore throat, a dry mouth, and a temperature as high as 39°C associated with chills. He had no confusion, nausea, vomiting, or changes in mental status. There was no history […]

Chapter 21: Some Cognitive Concepts

Case 62. A Message About Methods An 18-year-old woman with a history of acute lymphocytic leukemia (ALL) was admitted to the hospital with fever, chills, sweating, myalgias, and headache. With these symptoms, it sounds to me as if she is infected. It could also be her underlying disease, but that usually does not present in […]

Chapter 20: Cognitive Errors

Case 54. A Defective Detective Here we present two independently recorded discussions of a renal diagnostic problem, one by a medical intern and the other by an experienced nephrologist. Although we know little about the phylogeny of diagnostic acumen, it is instructive to compare the consecutive responses to the same clinical data of two individuals […]

Chapter 19: Examining Evidence

Case 48. A Difficult Tradeoff After spending more than 8 hours on an airplane, a 75-year-old physician with a passion for rock climbing had a pulmonary embolism. He did well with anticoagulation, although he noted some residual shortness of breath with exertion. His evaluation for possible clotting abnormalities was negative. His physician recommended that he […]

Chapter 18: Therapeutic Decision Making

Case 44. The Surgeon Opts to Operate: Why? A 38-year-old man with a 12-year history of ulcerative colitis was admitted to a community hospital with bloody diarrhea and abdominal pain. Campylobacter was found in his stool, and he was treated with a macrolide antibiotic for 10 days, but the diarrhea worsened. Sigmoidoscopy showed a diffuse, […]

Chapter 17: Diagnostic Verification

Case 37. A Point-by-Point Dissection of Clinical Reasoning We depart here from our usual framework of first presenting sequential case information and accompanying discussant’s remarks with analysis tacked on at the end. Instead, the analysis of the discussant’s remarks is presented directly in the text of her remarks. The comments in bold italics represent an […]

Chapter 16: Causal Reasoning

Case 32. Judging Causality A 55-year-old man with cancer was admitted to the hospital for progressive jaundice. Progressive jaundice in a man with cancer has many possible causes. His jaundice could be due to excessive red cell breakdown. Some cancers, particularly the B cell lymphomas, may produce immunoglobulins that cause a Coombs-positive hemolytic anemia. More […]

Chapter 15: Use and Interpretation of Diagnostic Tests

Case 20. Interpreting a Negative Test Result A 72-year-old woman with a history of mitral valve prolapse presented with a 3-week history of almost daily fevers and night sweats. In a patient like this with 3 weeks of fever, acute infections seem unlikely. Disorders such as pneumonia or a urinary tract infection (UTI) would present […]

Chapter 14: Refinement of Diagnostic Hypotheses

Case 10. What is a Differential Diagnosis? A 34-year-old coal miner from West Virginia was in good health until 4 weeks before admission, when he developed fever (40°C), drenching night sweats, diffuse myalgias, arthralgias, and nasal congestion. He failed to improve after a 5-day course of an oral macrolide antibiotic. This man’s occupation might provide […]