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Background There have been a few studies regarding the pre-attack symptoms (PAS) and pre-episode symptoms (PES) of cluster headache (CH), but none have been conducted in the Chinese population. The purpose of this study was to identify the prevalence and features of PAS and PES in Chinese patients, as well as to investigate their relationships with pertinent factors. Methods The study included patients who visited a tertiary headache center and nine other headache clinics between January 2019 and September 2021. A questionnaire was used to collect general data and information about PAS and PES. Results Among the 327 patients who met the CH criteria (International Classification of Headache Disorders, 3rd edition), 269 (82.3%) patients experienced at least one PAS. The most common PAS were head and facial discomfort (74.4%). Multivariable logistic regression analysis depicted that the number of triggers (OR = 1.798, p = 0.001), and smoking history (OR = 2.067, p = 0.026) were correlated with increased odds of PAS. In total, 68 (20.8%) patients had PES. The most common symptoms were head and facial discomfort (23, 33.8%). Multivariable logistic regression analysis showed that the number of triggers were associated with increased odds of PES (OR = 1.372, p = 0.005). Conclusions PAS are quite common in CH patients, demonstrating that CH attacks are not comprised of a pain phase alone; investigations of PAS and PES could help researchers better understand the pathophysiology of CH.

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This work is purposed to study the flow characteristics of rotor pumps including cavitation. First, a simplified two-dimensional numerical model is developed and computing strategies of the numerical analysis for cavitation are set up, including the selection of cavitation model and its parameters. Second, the reliability and accuracy of the two-dimensional numerical model are verified by experimental results. Then, several factors affecting the cavitation are discussed, including the rotational speeds, pressure differences, clearance sizes, and inlet pressures. For different rotational speeds and pressure differences, the mass flow rates with cavitation are a little larger than that without cavitation, but the amplitudes of the mass flow rates with cavitation are much larger than that without cavitation. Meanwhile, the volume fraction of the water vapor increases with the increasing speeds and the decreasing pressure differences. However, compared with the influence of rotational speeds, the influence of the pressure differences on the vapor contents is relatively smaller. Regarding the clearance size, the smaller the clearance size is, the stronger the cavitation will be. Furthermore, the clearance size between two rotors has a larger effect on the cavitation than that between rotor and pump case. For inlet pressure, it has a little effect on the mass flow rates when cavitation is not considered, but it presents a remarkable effect for the model with cavitation. In addition, the peaks of the volume fractions of vapor and the mass flow rates generally offset backward with the decreasing inlet pressures.