造血干细胞移植（HCT）在很多儿童恶性和非恶性疾病中得到应用。然而，这些患者在移植后容易出现紧急情况，这与既往存在的并存症和治疗基础疾病的方法、高剂量化疗方案相关的毒性、长时间骨髓抑制以及由于免疫功能低下而导致的机会性感染有关。紧急情况可能出现在准备阶段和造血祖细胞（HPC）输注中、移植后急性（移植前）和移植后晚期。感染并发症是围手术期死亡率和发病率最常见的原因。静脉窦梗阻综合症是一种儿童HCT中常见的危及生命的紧急情况，尤其是在婴儿中。及时识别和使用具有/不具有类固醇的抗凝血剂是管理这种并发症的关键。另一种并发症是移植相关性血栓性微血管病。如果不治疗，它可能导致多器官功能衰竭，需要紧急识别和使用亲和力阻滞剂（如厄洛昔单抗）进行管理。细胞因子释放综合征和细胞因子风暴是细胞治疗后常见的重要危及生命的并发症，需要急诊干预和重症监护以及使用托珠单抗。急性期的其他并发症包括但不限于：地比鱼精或其他化学治疗药物引起的癫痫、后可逆性脑病综合征、弥漫性肺出血、特发性肺综合征以及对干细胞输注的过敏反应。急性移植物抗宿主病（GvHD）是异基因HCT的主要毒性，特别是在减弱强度调节中，可以影响皮肤、肝脏、上、下消化道。已经对早期识别和分级GvHD进行了新生物标志物的重大发展，这使得应用治疗模式，如术后环磷酰胺和JAK / STAT抑制剂以预防和治疗GvHD成为可能。化疗导致的骨髓抑制增加了幼儿人群发生移植后综合征和凝血障碍的风险，从而增加了血凝和出血的风险。本文旨在回顾近年来有关儿童造血细胞移植（HCT）和细胞治疗中出现的并发症的最新文献，并提供关于HCT中主要紧急情况的全面总结。©2023 Agarwal，Rotz和Hanna。

Hematopoietic stem cell transplant (HCT) is used for many pediatric malignant and non-malignant diseases. However, these patients are at a high risk for emergencies post-transplant, related to prior comorbidities and treatments for the underlying disease, high dose chemotherapy regimen related toxicities, prolonged myelosuppression, and opportunistic infections due to their immunocompromised state. Emergencies can be during preparative regimen and hematopoietic progenitor cell (HPC) infusion, acute post-transplant (pre-engraftment) and late during post engraftment. Infectious complications are the most common cause of morbidity and mortality in the peri-transplant period. Sinusoidal obstructive syndrome is another life-threatening emergency seen in children undergoing HCT, especially in infants. Timely recognition and administration of defibrotide with/without steroids is key to the management of this complication. Another complication seen is transplant associated thrombotic microangiopathy. It can cause multiorgan failure if left untreated and demands urgent identification and management with complement blockade agents such as eculizumab. Cytokine release syndrome and cytokine storm is an important life-threatening complication seen after cellular therapy, and needs emergent intervention with ICU supportive care and tocilizumab. Other complications in acute period include but are not limited to: seizures from busulfan or other chemotherapy agents, PRES (posterior reversible encephalopathy syndrome), diffuse alveolar hemorrhage, idiopathic pulmonary syndrome and allergic reaction to infusion of stem cells. Acute graft versus host disease (GvHD) is a major toxicity of allogeneic HCT, especially with reduced intensity conditioning, that can affect the skin, liver, upper and lower gastrointestinal tract. There has been major development in new biomarkers for early identification and grading of GvHD, which enables application of treatment modalities such as post-transplant cyclophosphamide and JAK/STAT inhibitors to prevent and treat GvHD. Myelosuppression secondary to the chemotherapy increases risk for engraftment syndrome as well as coagulopathies, thus increasing the risk for clotting and bleeding in the pediatric population. The purpose of this article is to review recent literature in these complications seen with pediatric hematopoietic cell transplant (HCT) and cellular therapies and provide a comprehensive summary of the major emergencies seen with HCT.© 2023 Agarwal, Rotz and Hanna.