[The Turning Point of Diagnostic Process for Infectious Disease of Nervous System]

Infectious diseases of the nervous system are a group of diseases; timely diagnosis and treatment for these diseases determines the effect of prognosis on life and functions. Diagnosis itself is not very difficult in cases presenting with typical symptoms. However, if mild and atypical symptoms have been present for long, the underlying disease may not be easily recognized as a neurological disease or infectious disorder, and the diagnosis may be delayed. Furthermore, neurologists may not always be able to examine patients from the first visit itself. In this chapter, I present three cases with mild and atypical initial symptoms. The first case involved a patient with tetanus, whose initial symptom was dysphagia, and the onset of trismus was the turning point for diagnosis. The second case involved a patient with herpes simplex encephalitis. Dyshydrosis and dysosmia were the initial symptoms, and the appearance of disorientation, fever, and consciousness disturbance helped in achieving the final diagnosis. The last case was of a patient with Japanese encephalitis, whose initial symptoms were fever and parkinsonism. A recent history of surgery for gastric cancer, disease onset in the summer season, and living with neighbors on pig farms was indicative of Japanese encephalitis.