Dynamic nasopharyngeal collapse (NPC) is an obstructive upper airway disease that affects mainly the inspiratory phase of respiration in horses undergoing strenuous exercise. It occurs when the neuromuscular activity of the nasopharynx is overwhelmed by the intense negative pressures generated during exercise. This leads to collapse of at least one of the four components of the nasopharynx which is comprised of the two lateral walls, the dorsal roof and the ventral soft palate. As a result, the airway diameter and thus airflow become compromised. Even small changes in the airway diameter produces profound increases in negative inspiratory pressure, perpetuating the cycle of collapse. Compared to other dynamic upper respiratory tract disorders, the amount of literature on NPC as a disease entity is limited. The exact pathophysiology of NPC is unknown; however, it impacts up to one quarter of high-performance equine athletes presenting for poor performance. There is currently no definitive treatment for this severely performance-limiting condition. Thus, the prognosis for future athletic prognosis is guarded, with most horses being retired from racing or athletic use in general. Further research is warranted in this field to reduce the impact of disease and in turn, reduce the turnover rate and economic loss by enhancing the career longevity of elite equine athletes diagnosed with NPC.

中文翻译：

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马的动态鼻咽塌陷：迄今为止我们所知道的

动态鼻咽塌陷（NPC）是一种阻塞性上呼吸道疾病，主要影响剧烈运动的马呼吸的吸气相。当鼻咽部的神经肌肉活动被运动过程中产生的强烈负压淹没时，就会发生这种情况。这导致鼻咽的四个部件中的至少一个塌陷，鼻咽部件由两个侧壁、背顶和腹侧软腭组成。结果，气道直径和气流受到损害。即使气道直径发生微小变化，也会导致吸气负压大幅增加，从而使虚脱循环持续下去。与其他动态上呼吸道疾病相比，有关鼻咽癌作为疾病实体的文献数量有限。NPC 的确切病理生理学尚不清楚；然而，它影响了多达四分之一表现不佳的高水平马术运动员。目前还没有针对这种严重影响表现的病症的明确治疗方法。因此，对未来运动预后的预测是谨慎的，大多数马匹从比赛或一般运动用途中退役。该领域需要进一步研究，以减少疾病的影响，从而通过延长被诊断患有鼻咽癌的精英马运动员的职业寿命来减少离职率和经济损失。