Yun Zhang, Ting Gao, Qing-Qing Tao

The number of cognitive deterioration patients has been steadily increasing as the population ages in China. Patients with cognitive deterioration demonstrated diverse patterns, often making the diagnosis difficult, especially in rapidly progressive cognitive deterioration (RPCD) patients. The purpose of this study was to exhibit the disease spectrum and frequency of noncerebrovascular RPCD in patients from a medical college hospital of southeastern China. We performed a 2-year retrospective cohort study including 310 RPCD patients who had been admitted to the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, from January 1, 2015 to December 31, 2016. RPCD patients' information on epidemiologic data and clinical aspects were collected. All the data were analyzed using SPSS. Of a total of 310 patients hospitalized for RPCD diagnosis, mean age of onset was 55.92±18.89 years. The most common cause of RPCD was viral encephalitis, accounting for 21.9% (68) of the cases, followed by Alzheimer's disease and autoimmune encephalitis, accounting for 14.5% (45) and 9.0% (28) of the cases, respectively. Creutzfeldt-Jakob disease accounted for 7.1% (22) of the cases. Patients in the secondary RPCD group tended to be younger than those in the primary RPCD group and experienced a more rapid progression course. Our study suggests that the most common causes of RPCD are secondary neurological diseases and most of them are potentially reversible under appropriate treatment of the underlying disease. The spectrum and frequency of RPCD in our cohort is comparable with a previous study performed in the European population.