This paper discusses on one hand, the phenomenon of war through the medical mutations occurred within the First World War, the moment in history which inaugurates the "Total War", characterized by the implication of all civil society in the conflict. On the other hand, the transformations in medical sciences are approached as a whole of knowledges and practises during the Great War, since the development of certain techniques as the electro-diagnostic, emerged in response to the appearance of unexpected pathologies, as the "shell shock". In this way, it is showed how medical sciences improve certain epistemic and technological developments that would not be visible in peaceful times. This analysis allow us to perceive the evolution in electrotherapy domain and how it became a military tool for distinguishing the shell shock patients, from others who simulated to be incapacitated to keep on fighting. Furthermore, the example of shell shock proposes the larger philosophical discussion about the historical and cultural aspects in defining pathologies in the history of medicine.