## 4 Results  
The results of the descriptive statistics characterize both studied cohorts, including the retrospectively and the prospectively analyzed patients, as follows: (1) a ret rospective analysis of 402 medical records of newborn children (291 children, 57.1%; 95% CI [54.91-59.29]) and those aged between 28 days and 18 years (111 children, 21.8%; 95% CI [19.97-23.63]), diagnosed with neonatal or pediatric ischemic stroke between 2010 and 2016 in the neurology departments of IMSP IMC and IMSP SCM No. 1; and (2) a prospective study from 2017 to 2020 within the same medical institutions, with a sample of 108 children aged 0 to 18 years, distributed by age categories: newborn--71 (65.7%; 95% CI [61.13-70.27]), children aged between 28 days and 18 years (meeting pediatric ischemic stroke criteria)--37 (28.7%; 95% CI [24.35-33.05]), all diagnosed with acute ischemic stroke. To analyze epidemiological aspects, clinical manifestations, and neurological outcomes in both retrospective and prospective studies, data from 510 medical records of childhood acute stroke cases were examined, distributed by age categories: newborn--362 (71%, 95% CI [68.99-73.01]), child--148 (29%, 95% CI [26.99-31.01]). Imaging, neurofunctional, and immunological manifestations were analyzed based on results obtained from the 108 patients with ischemic stroke in the prospective study. The study of the clinical manifestations of IS in children across different age groups is crucial in this field. IS cases were predominantly diagnosed in newborns, with 362 cases (71%, 95% CI 68.99-73.01), while 148 cases (29%, 95% CI 26.99-31.01) occurred after 28 days of birth. Among newborns with IS, 242 (66.9%, 95% CI 64.43-69.37) were boys and 120 (33.1%, 95% CI 30.63-35.57) were girls. Perinatal IS is defined in the specialized literature as an acute neurological syndrome of vascular origin, occurring between 20 weeks of gestation and 28 days after birth, confirmed by neuroimaging or neuropathological studies, and leading to neurological outcomes. Clinical manifestations in this group of children are less specific, with seizures, apnea, and impaired consciousness being the most common. In the pediatric population, perinatal IS accounts for 25% of IS cases and 43% of cavernous sinus thrombosis cases. The analysis of IS clinical manifestations revealed differences compared to other age groups, characterized by several generalized symptoms (refer to Table 1), associated with age-specific nervous system development. Table 1 illustrates that 88.7% of newborns with ischemic stroke experienced convulsive seizures, with 65.7% exhibiting focal manifestations. The most prevalent clinical symptoms were apnea attacks, impaired consciousness, and movement disorders, while tremors, pathologic irritability, and converging strabismus were less frequent. However, it is important to include pathologic irritability in the algorithm for decision-making, as it represents an alarming sign. To interpret that, a brief difference to physiologic irritability is emphasized: Physiological irritability typically increases in the early weeks of life, peaks around 6-8 weeks of age, and generally improves by 3-4 months of age. In contrast, pathological irritability is characterized by excessive and relentless crying, which may lead to hypoxia and even epileptic seizures. This is a significant risk factor for abusive