Stroke occurrence is not randomly distributed over time but has circadian rhythmicity with the highest frequency of onset in the morning hours. This specific temporal pattern is valid for all subtypes of cerebral infarction and intracerebral hemorrhage. It also correlates with the circadian variation of some exogenous factors such as orthostatic changes, physical activity, sleep-awake cycle, as well as with endogenous factors including dipping patterns of blood pressure, or morning prothrombotic and hypofibrinolytic states with underlying cyclic changes in the autonomous system and humoral activity. Since the internal clock is responsible for these circadian biological changes, its disruption may increase the risk of stroke occurrence and influence neuronal susceptibility to injury and neurorehabilitation. This review aims to summarize the literature data on the circadian variation of cerebrovascular events according to physiological, cellular, and molecular circadian changes, to survey the available information on the chronotherapy and chronoprophylaxis of stroke and its risk factors, as well as to discuss the less reviewed impact of the circadian rhythm in stroke onset on patient outcome and functional status after stroke.

Aims and background.The circadian pattern of stroke occurrence variation has been recognized with certain differences between authors and stroke types. The underlying reason may be related to exogenous factors (cyclic physical activity, including sleep–awake cycles and assuming the up-right posture) and endogenous factors, with their diurnal variation (blood pressure, hemostatic balance, autonomic system activity). The aims of the present study are to investigate the existence of a circadian variation of stroke and the possible differences between stroke subtypes in the Cluj Napoca area.Materials and method.The stroke event data were acquired from the Patient Records of a consecutive series of 1083 patients admitted through the Emergency Room at Neurology Departments I and II of the District Hospital of Cluj Napoca, between 1 January 2012 and 31 December 2012. The classifiable onset time was assigned to one of four six-hour intervals: 00.01–06.00 (night), 06.01–12.00 (morning), 12.01–18.00 (afternoon) and 18.01–24.00 (evening). Demographic data and vascular risk factors were recorded.Results.All three stroke types (ischemic stroke, hemorrhagic stroke and subarachnoid hemorrhage) have shown a circadian variation regarding their occurrence, with the peak of incidence in the morning and the nadir during nighttime. This circadian pattern is independent by demographic factors and vascular risk factors.Conclusion.Our study confirmed the circadian variation of onset occurrence for all stroke subtypes. Some triggering factors promote ischemic stroke and prevent hemorrhagic stroke. The diurnal pattern of variation with the higher incidence in the morning and the lower in the night may lead to chrono-therapeutic and preventive approach (chrono-therapy of the risk factors), which targets the period of the highest vulnerability after awaking.

The ucMGP assay can be used for determination of MGP in SF, and combined assessment of ucMGP in serum and SF could potentially serve as a joint inflammatory marker in arthritis patients.

Introduction. Cerebrovascular events are not randomly distributed over time. In addition to the better known circadian variation, a seasonal variation in stroke occurrence is described in different reports. The aim of our study was to investigate whether stroke with its types follows a seasonal occurrence pattern in the Cluj-Napoca area. Materials and method. The stroke event data were collected from the patient records of a consecutive series of 1083 patients admitted through the Emergency Room to the Neurology Departments I and II of the County Hospital Cluj-Napoca, between 1 January 2012 and 31 December 2012. The diagnosis of ischemic stroke, intracerebral hemorrhage and subarachnoid hemorrhage was confirmed by neurologic examination and neuroimaging, according to updated World Health Organization criteria. The onset time was assigned to one of the four seasons: spring (March to May), summer (June to August), autumn (September to November) and winter (December to February). Statistical analysis was performed using Excel Microsoft. Results. All three types of stroke (ischemic stroke, intracerebral hemorrhage and subarachnoid hemorrhage) showed a seasonal variation in their occurrence, with two peaks in the winter and in the summer. Conclusion. The knowledge of the seasonal variation pattern of stroke occurrence could provide a basis for preventive and therapeutic strategies in cerebrovascular pathology.

Introduction. The circadian variation of ischemic stroke onset is known, but its impact on recovery prognosis has been less studied. Materials and method. The study included 32 patients with ischemic stroke, admitted to Neurology Departments I and II of the Rehabilitation Hospital in Cluj-Napoca between 1 June 2008 and 31 December 2009 and followed up for 2 years, during 5 successive admissions. The diagnosis of ischemic stroke was defined according to updated World Health Organization criteria. The onset time of ischemic stroke was assigned to one of the following six-hour intervals