Il concetto di "diagnosi fuzzy": una applicazione alla malattia di Anderson-Fabry

To ensure high diagnostic reliability, the traditional classification of the diseases is based on two fundamental criteria: the presence of peculiar characteristics that identify a disease distinguishing it from the others; and the detection of causes or multifactorial correlation. This idea is based on rules that refer to the principles of classical logic, which however cannot be considered an appropriate tool in medicine. It may prove to be a useful tool in case of "prototypical" manifestations of a disease, but not for a lot of pathologies that appear as complex and inconsistent cases, or characterized (on the etiological plane) by an interrelation between possible causes and trigger factors, and (on the clinical plane) by an high individual variability. The diagnosis of such diseases requires a logic through which it is possible to categorize the world of real objects. The article examines the fuzzy logic as a tool for the diagnostic reasoning, and particularly the "fuzzy set" and "fuzzy diagnosis" concepts, in order to verify its possible use in the diagnosis of a rare disease with complex etiology: the Anderson-Fabry disease. Our analysis underlines the practical (and not theoretical) purpose of the diagnosis, which gives it an ethical value. From this point of view, the article suggests, in the last part, some ethical criteria in the balance carried out by the clinician between the risk concerning the formulation of a "fuzzy" diagnostic hypothesis and the advantages of an early diagnosis for the patients, especially considering the availability of innovative pharmacological treatments.