呼吸
词汇介绍
拓展阅读
解析
Pneumocystosis /njuːməsɪs'təʊsɪs/
释 义 [内科] 肺孢子虫病
例 句 Artemisinin is also a promising potent drug in treatment of cancer, human parasites such as schistosomiasis, pneumocystosis and AIDS complication. 同时青蒿素也是治疗癌症、血吸虫病等人类寄生虫、肺孢子菌病、艾滋病并发症的有效药物。
概述
疾病概述
肺孢子菌病是由潜伏的肺孢子菌,在机体免疫抑制或受损时大量繁殖,破坏肺泡细胞,引起间质性肺炎即肺孢子菌肺炎。肺孢子菌肺炎尤其多见于艾滋病患者,也是其重要的致死原因;而器官移植、免疫抑制药物的广泛开展和应用,是肺孢子菌肺炎发病率上升的另一重要原因。主要临床表现为发热、干咳、进行性呼吸困难等,单纯吸氧不能缓解,经对因治疗后可迅速恢复。
致病因素或病理机制
肺孢子菌为毒力较弱,生长缓慢。健康人感染后多无病理损伤,且多呈隐性感染,只有在机体免疫功能缺陷或低下的患者才可能发生显性感染。目前肺孢子菌的具体发病机制尚不明确。认为被吸入下呼吸道的肺孢子菌,黏附寄生于人体Ⅰ型肺泡上皮细胞表面,当免疫功能低下时大量繁殖,直接导致Ⅰ型肺泡上皮细胞损伤并坏死,肺泡毛细血管通透性增加,肺泡内充满肺孢子菌、纤维蛋白、脱落的上皮细胞、淋巴细胞、浆细胞等,使肺泡的表面活性物质减少,影响气体交换,出现低氧血症。为清除肺泡内渗出物,肺泡Ⅱ型上皮细胞代偿性肥大,肺泡间隙上皮细胞增生、肥厚、部分脱落,同时间质内巨噬细胞和浆细胞增生,间质纤维化,造成肺功能严重障碍。
症状表现
潜伏期多为 1-2 个月,临床上通常分为两种类型:(1)流行型或经典型多发在早产儿、营养不良儿,易在育婴机构或居住拥挤环境中流行。隐袭性起病,进展缓慢,初期常有全身不适、食欲下降、低热、腹泻、体重下降,逐渐出现气促、干咳、进行性呼吸困难、鼻翼扇动、发绀。患儿症状虽重但肺部体征相对轻微。整个病程约 2-12周,患儿多死于呼吸衰竭,病死率可达 50%。(2)散发型或现代型多见于有免疫缺陷(先天或后天获得)的儿童或成人。最常见于艾滋病患者。病初食欲缺乏、体重降低,后出现干咳、气促、发绀,可伴有发热,最终导致呼吸衰竭,数天内死亡。通常疾病症状的严重程度与肺部体征不成比例,即肺部阳性体征缺如,或可闻及少量散在的干、湿啰音。有明显的低氧血症,晚期出现呼吸性酸中毒。AIDS 者肺功能损害更明显。未经治疗可100%死于呼吸衰竭。对于 AIDS 患者、恶性肿瘤接受抗癌治疗或器官移植后接受免疫抑制剂治疗者、未成熟儿、营养不良和衰弱婴儿等,在病程中出现无明显原因的发热、干咳、呼吸急促等症状时应考虑本病的可能,尤其患者呼吸困难症状明显而体征甚少时应高度警惕本病。
诊断依据
(1)缓慢或亚急性起病,发热、干咳、发绀、进行性呼吸困难。(2)临床症状重,但肺部阳性体征少。(3)X 线检查符合间质性肺炎改变。(4)低氧血症。(5)血乳酸脱氢酶常升高。(6)确诊依靠病原学检查如痰液、BALF、肺组织活检等发现肺孢子菌的包囊或滋养体。
凡免疫功能低下或缺陷的患者以及长期接受免疫抑制药物治疗的患者,出现上述症状应高度怀疑该病的存在:对于临床高度怀疑本病而未找到病原学证据时可以进行试验性治疗。本病应与细菌(包括结核菌)、病毒、衣原体、真菌感染引起的肺部疾病进行鉴别。
微创组织取样对南非儿童死亡的特定原因进行归因的潜力: 一项初步的流行病学研究。
发表时间:2019-10-09
影响指数:9.1
作者: Chawana R
期刊:Clin. Infect. Dis.
Data are presented as No. (%). Main row headings indicate the underlying cause of death, with immediate causes of death below.Abbreviation: HIV, human immunodeficiency virus.a Categorized according to the United Nations Inter-agency Group on Child Mortality Estimation classification categories.b One pneumonia case had HIV lymphoid interstitial pneumonitis as a coimmediate cause of death.c This case of rotavirus gastroenteritis also had a pneumonia as a coimmediate cause of death.d The underlying conditions in infants included neonatal jaundice from other hepatocellular damage (n = 1), pneumocystosis (n = 1), and tuberculosis (n = 1). The underlying conditions in children included hepatitis A with coma (n = 2), protein energy malnutrition, unspecified (n = 1), and tuberculosis (n = 2). The underlying condition in older children included chickenpox (varicella) (n = 1).e One case of nosocomial Pseudomonas pneumonia also had nosocomial Escherichia coli meningitis as a coimmediate cause of death; the immediate cause of death in this case is recorded as meningitis.f This case of congestive heart failure also had congenital hypoplasia and dysplasia of the lung as a coimmediate cause of death.g This case of nosocomial Staphylococcus aureus pneumonia also had nosocomial disseminated herpes simplex virus infection as a coimmediate cause of death.
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