ABSTRACT
Objective: To elaborate the clinical characteristics of congenital pulmonary lymphangiectasia in a neonate with hydrops fetalis. This could be an alert in considering it as a differential diagnosis for neonates with acute respiratory failure. Methods: We reviewed and analyzed single-center registry patients who underwent cadaveric autopsies in the Department of Pathology at Children's Hospital from January 1, 2010 to December 31, 2021. We aimed to explore the perinatal clinical manifestations associated with congenital pulmonary lymphangiectasis (CPL). Literature was reviewed to summarize the common features of CPL in pregnancy from individual cases, and to facilitate prenatal and intrapartum diagnosis prognosis, and assessment of medical emergencies. Results: Thirty-four patients were included, and the main causes of death were intrauterine infection (n = 6), severe pneumonia (n = 11), spontaneous pneumothorax (n = 3), hemorrhagic shock (n = 2), CPL (n = 1), and other non-respiratory failure manifestations (n = 12). The manifestations of respiratory distress in CPL were different from those of intrauterine infections and respiratory failure due to parenchymal lung lesions. These include prenatal presentation of fetal edema, postnatal presentation of uncorrectable respiratory failure with severe hypoproteinemia, pneumothorax and interstitial emphysema on imaging, and poor response to treatment with surfactant-like substances. Thus, when the pregnancy tests reveal fetal edema and postnatal presentation of acute, respiratory distress, the diagnosis of CPL should be considered first, and corresponding medical care should be implemented to improve the survival rate. Conclusions: CPL is a rare pulmonary defect, and its perinatal clinical manifestations can often be neglected. For children with prenatal fetal edema who die after birth due to progressive respiratory distress, a timely autopsy is of utmost importance to clarify the etiology, improve understanding of CPL, and diagnose early to allow for proper prenatal and postnatal care.
ABSTRACT
A vortex is a common ratchet phenomenon in active systems. The spatial symmetry is usually broken by introducing asymmetric shapes or spontaneously by collective motion in the presence of hydrodynamic interactions or other alignment effects. Unexpectedly, we observe, by simulations, the formation of a vortex in the simplest model of a circular obstacle immersed in a bath of spherical self-propelled particles. No symmetry-breaking factors mentioned above are included in this model. The vortex forms only when the particle activity is high, i.e. large persistence. The obstacle size is also a key factor and the vortex only forms in a limited range of obstacle sizes. The sustainment of the vortex originates from the bias of the rotating particle cluster around the obstacle in accepting the incoming particles based on their propelling directions. Our results provide new understanding of and insights into the spontaneous symmetry-breaking and ratchet phenomena in active matter.
