预后不良的因素
与转归情况差(进入重症监护室或死亡)有关的预后因素包括年龄较大和存在并发病,如糖尿病、乙型肝炎病毒感染和心脏病等。[11]Peiris JS, Chu CM, Cheng VC, et al. Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study. Lancet. 2003;361:1767-1772.http://www.ncbi.nlm.nih.gov/pubmed/12781535?tool=bestpractice.com[24]Lee N, Hui D, Wu A, et al. A major outbreak of severe acute respiratory syndrome in Hong Kong. N Engl J Med. 2003;348:1986-1994.http://www.nejm.org/doi/full/10.1056/NEJMoa030685http://www.ncbi.nlm.nih.gov/pubmed/12682352?tool=bestpractice.com[25]Booth CM, Matukas LM, Tomlinson GA, et al. Clinical features and short-term outcomes of 144 patients with SARS in the greater Toronto area. JAMA. 2003;289:2801-2809.http://www.ncbi.nlm.nih.gov/pubmed/12734147?tool=bestpractice.com[74]Tsui PT, Kwok ML, Yuen H, et al. Severe acute respiratory syndrome: clinical outcome and prognostic correlates. Emerg Infect Dis. 2003;9:1064-1069.http://www.ncbi.nlm.nih.gov/pubmed/14519241?tool=bestpractice.com[75]Chan JW, Ng CK, Chan YH, et al. Short term outcome and risk factors for adverse clinical outcomes in adults with severe acute respiratory syndrome (SARS). Thorax. 2003;58;686-689.http://www.ncbi.nlm.nih.gov/pubmed/12885985?tool=bestpractice.com
表现为 LDH 水平升高、CRP 升高、中性粒细胞数量高 [24]Lee N, Hui D, Wu A, et al. A major outbreak of severe acute respiratory syndrome in Hong Kong. N Engl J Med. 2003;348:1986-1994.http://www.nejm.org/doi/full/10.1056/NEJMoa030685http://www.ncbi.nlm.nih.gov/pubmed/12682352?tool=bestpractice.com[74]Tsui PT, Kwok ML, Yuen H, et al. Severe acute respiratory syndrome: clinical outcome and prognostic correlates. Emerg Infect Dis. 2003;9:1064-1069.http://www.ncbi.nlm.nih.gov/pubmed/14519241?tool=bestpractice.com 以及 CD4 和 CD8 淋巴细胞数量低[76]Wong RS, Wu A, To KF, et al. Haematological manifestations in patients with severe acute respiratory syndrome: retrospective analysis. BMJ. 2003;326:1358-1362.http://www.bmj.com/content/326/7403/1358http://www.ncbi.nlm.nih.gov/pubmed/12816821?tool=bestpractice.com 也与独立的死亡风险增高有关。
发病率和死亡率
发生需要进行插管和机械通气的临床病情恶化的时间中位值是在出现症状后 8 日。[1]Christian MD, Poutanen SM, Loutfy MR, et al. Severe acute respiratory syndrome. Clin Infect Dis. 2004;38:1420-1427.http://cid.oxfordjournals.org/content/38/10/1420.longhttp://www.ncbi.nlm.nih.gov/pubmed/15156481?tool=bestpractice.com 最容易导致死亡的原因是脓毒症、ARDS 和多器官衰竭。[77]Lew TW, Kwek TK, Tai D, et al. Acute respiratory distress syndrome in critically ill patients with severe acute respiratory syndrome. JAMA. 2003;290:374-380.http://www.ncbi.nlm.nih.gov/pubmed/12865379?tool=bestpractice.com
2003 年重症急性呼吸综合征疫情暴发期间的病死率为 9.6%,其范围在 0% 至 40% 之间。[2]World Health Organization: global alert and response (GAR). Summary of probable SARS cases with onset of illness from 1 November 2002 to 31 July 2003. December 2003 [internet publication].http://www.who.int/csr/sars/country/table2004_04_21/en/ 年龄在 65 岁以上的患者的死亡率超过 50%。
在重症急性呼吸综合征幸存者中,经常观察到残余肺功能降低、持续性的放射影像异常,以及长时间存在的心理后遗症和肌无力,尽管这些症状会随着时间推移而改善。[78]Chan KS, Zheng JP, Mok YW, et al. SARS: prognosis, outcome and sequelae. Respirology. 2003;8:S36-S40.http://www.ncbi.nlm.nih.gov/pubmed/15018132?tool=bestpractice.com
儿童(年龄 <12 岁)
儿童的临床症状较为温和,且临床病程也较短,与普通感冒类似。[37]Hon KL, Leung CW, Cheng WT, et al. Clinical presentations and outcome of severe acute respiratory syndrome in children. Lancet. 2003;361:1701-1703.http://www.ncbi.nlm.nih.gov/pubmed/12767737?tool=bestpractice.com[79]Chiu WK, Cheung PC, Ng KL, et al. Severe acute respiratory syndrome in children: experience in a regional hospital in Hong Kong. Pediatr Crit Care Med. 2003;4:279-283.http://www.ncbi.nlm.nih.gov/pubmed/12831407?tool=bestpractice.com[80]Bitnun A, Allen U, Heurter H, et al. Children hospitalized with severe acute respiratory syndrome-related illness in Toronto. Pediatrics. 2003;112:e261.http://pediatrics.aappublications.org/content/112/4/e261.fullhttp://www.ncbi.nlm.nih.gov/pubmed/14523209?tool=bestpractice.com 因此,与成人患者相比,儿童患者的预后较好,在被重症急性呼吸综合征冠状病毒感染的低龄儿童中,尚未报告有死亡情况。