This book helps doctors and students to arrive at a diagnosis, and to explain and to justify their reasoning, especially when seeing patients with new problems that lie outside their personal range of experience. This will happen very frequently to students, frequently to house officers, but will still happen regularly to very experienced senior hospital doctors and general practitioners.
The book adopts the approach used by experienced diagnosticians, by focusing on the finding with the shortest differential diagnosis (i.e. the best diagnostic lead). It describes the differential diagnoses of such findings that may be encountered by a reader in the history, examination and usual preliminary tests and how the diagnoses can be confirmed. It describes what tactics to adopt in order to find better leads, while not losing sight of the patient’s original concern. The probability and set theory of this process is explained in Chapter 13.
The entries on each page of the book resemble a traditional past medical history with multiple diagnoses. The reader scans down the page to see which of the diagnoses with its findings match the patient’s findings so far. The compatible findings can then be used as evidence for the diagnosis and treatment, to be shared with the patient and other members of the multidisciplinary team, such as nurses, pharmacists, physiotherapists, and other professionals allied to medicine. It can be used to create high-quality discharge or handover summaries.
Patients or their carers may wish to share in the diagnostic and decision-making process. In order to do this, they need to know what problems have been identified and the tests and treatments being proposed. They will need to know which of these diagnoses explain each problem and treatment. They may also need to know which findings are being used to confirm each diagnosis, and to choose its treatments and to mark the outcome. The book describes how this information can be provided in writing. The patient or carer will then be in a position to explain all this to another doctor, if necessary.
In this third edition, there are sections on each page that show how the diagnosis may be finalized by the outcome of management. This replaces the section in the second edition that described the ‘initial management’ of the condition. The purpose of this is to show how the response of treatment, etc., affects the diagnostic process. Chest X-ray images have been added to illustrate the findings in Chapter 12. The appendix of the second edition has been replaced by Chapter 13 in this third edition and explains the basis of evidence-based differential diagnosis and diagnostic confirmation.