Fundamentals of internal medicine

Abstract

The most important diagnostic tools available to the internist are the patient history and physical examination, after which a plan must be made for further diagnostic evaluation and treatment. For this the internist uses clinical reasoning based on his or her knowledge of evidence-based medicine and pathobiology. Pathobiology is primarily concerned with the question of how something works; evidence-based medicine is concerned with whether something works, and if so, how often or how much on average. Diseases do not exist in their own right and diagnostic criteria are based on consensus. A diagnosis of a ‘disease’ is based on observations of patients as well as our opinions, be they right or wrong, regarding its causes. It is important to distinguish between ‘partial causes’ and a ‘causative complement’. Because of these concepts, the biological relevance of a partial cause in the development of a disease cannot be derived from the strength of the link between it and the disease. Our opinions regarding the cause of disease appear to be based on induction. However, induction is not a good foundation from which to determine causation. Hypotheses on the causes of disease cannot be proved. They can, however, be refuted. Education, training, research and patient care all depend on effective communication. Communication is enhanced if the thesis is provided first followed by the arguments to support it. Hence, transfer of patient information such as during a morning report should begin with a working diagnosis (the ‘thesis’) and thereafter the findings of patient history and other relevant data (the ‘arguments’). At the present time, too little attention is devoted in education and continuing education in internal medicine to these aspects of clinical reasoning and communication.