[Fundamentals of internal medicine]

The most important diagnostic tools of 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 our observation of patients as well as our opinions, whether right or wrong, regarding its cause. It is important to distinguish between 'partial causes' and a 'causative complement'. As a result of this concept, 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 cause of disease cannot be proved. They can, however, be disproved. Education, training, research and patient care all depend on effective communication. Communication is enhanced if the thesis is given first and thereafter the arguments. 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, et cetera (the 'arguments'). At this time, too little attention is given to these branches of clinical reasoning and communication in education and continuing education in internal medicine.