Bedside reasoning on causes and mechanisms of diseases in the era of precision medicine: a timeless story?

Abstract

This is a short reflection about bedside reasoning in clinical medicine, emphasizing the importance of distinguishing between causes and mechanisms of diseases. All complex/sporadic diseases result from interactions between a genetic predisposition and environmental factors. The main disease mechanisms resulting in clinical signs involve inflammation, insult of vessels or nerves, pharmacological or hormonal dysfunction, altered metabolism and overload, tumoral proliferations, intrinsic dysfunction, malformation and traumatism. Different mechanisms can occur during the same disease process. The practical consequences of identifying causes and mechanisms of diseases are illustrated. As a unifying concept, a very simple diagnostic flow chart that puts the patient, and not the disease, into centre of reflection and that bridges the gap between basic knowledge and patient care is provided. This diagnostic flow chart helps both the experienced physician and the medical student to perform a complete diagnostic process, addressing the specificities of the clinical findings, the pathogenesis and the causative factors, an aim that has become possible in the era of precision medicine. Two examples of patients with a dermatologic presentation highlight this diagnostic process, which paves the way to rational therapy and to translational research.