Influence of Autonomic Regulation on Peripheral Blood Flow in Children With Acute Pneumonia

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Introduction. Community-acquired pneumonia (CAP) in children remains one of the most frequent and clinically significant respiratory diseases. Its pathogenesis involves not only a localized infectious-inflammatory process in lung tissue but also systemic responses that extend beyond the respiratory system. Among these, alterations in hemodynamics, disturbances of microcirculation, and dysfunction of the autonomic nervous system play a crucial role. Understanding these systemic changes is essential for clarifying mechanisms of prolonged recovery and potential complications, even after resolution of acute symptoms. Materials and Methods. The study enrolled 30 children aged 8–12 years diagnosed with CAP in the early recovery period, compared with a control group of 30 age-matched healthy children. Nailfold capillaroscopy was performed using a USB microscope to assess microcirculatory parameters, including density and perfusion characteristics of capillaries. Autonomic nervous system function was evaluated by orthostatic testing and the Valsalva maneuver, which allowed sympathetic and parasympathetic balance estimation. Results. Children recovering from CAP demonstrated autonomic imbalance with sympathetic predominance. Orthostatic test responses were significantly elevated compared to controls (1.51±0.07 vs. 1.39±0.04 points, p<0.05). In contrast, Valsalva maneuver results were reduced in CAP patients (1.40±0.09) compared to healthy peers (1.63±0.08), indicating diminished parasympathetic modulation. Capillaroscopy revealed reduced density of functioning capillaries, increased perfusion heterogeneity, and decreased overall perfusion, consistent with precapillary arteriolar vasoconstriction. Conclusions. This study highlights that children with CAP, even during early recovery, continue to exhibit autonomic imbalance characterized by sympathetic predominance. These changes provoke functional deterioration of the microcirculatory bed, potentially contributing to local tissue hypoxia and systemic complications. The demonstrated link between autonomic regulation and microvascular function provides new insights into pathophysiology and may suggest novel therapeutic targets aimed at restoring autonomic balance and improving microcirculatory function.