如果患者在发病后一周内接受治疗,通常症状可得到明显改善,如在开始使用多西环素治疗 72 小时内可退热;若无症状改善则说明需要考虑其他诊断。[1]Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States. MMWR Recomm Rep. 2016;65:1-44.http://www.cdc.gov/mmwr/volumes/65/rr/rr6502a1.htmhttp://www.ncbi.nlm.nih.gov/pubmed/27172113?tool=bestpractice.com[6]Buckingham SC, Marshall GS, Schutze GE, et al. Clinical and laboratory features, hospital course, and outcome of Rocky Mountain spotted fever in children. J Pediatr. 2007;150:180-184.http://www.ncbi.nlm.nih.gov/pubmed/17236897?tool=bestpractice.com
死亡率
多数患者可完全治愈,尤其是在发病后 5 天内即采取适当抗生素治疗的患者。在无抗生素的时代,大约 30% 的落基山斑疹热 (RMSF) 患者死亡。随着支持性治疗的改善以及有效抗生素的开发,病死率稳步下降。自 2001 年来,在美国报告的 RMSF 患者中,仅有不到 1% 的病例死亡。[2]Drexler NA, Dahlgren FS, Heitman KN, et al. National surveillance of spotted fever group rickettsioses in the United States, 2008-2012. Am J Trop Med Hyg. 2016;94:26-34.http://www.ncbi.nlm.nih.gov/pubmed/26324732?tool=bestpractice.com[3]Openshaw JJ, Swerdlow DL, Krebs JW, et al. Rocky mountain spotted fever in the United States, 2000-2007: interpreting contemporary increases in incidence. Am J Trop Med Hyg. 2010;83:174-182.http://www.ajtmh.org/content/83/1/174.longhttp://www.ncbi.nlm.nih.gov/pubmed/20595498?tool=bestpractice.com造成 RMSF 患者死亡的最大危险因素是延迟使用合适的抗生素治疗。死亡率:有中等质量证据表明,在发病后 5 天内给予患者合适的抗生素治疗可以显著降低死亡风险。[17]Holman RC, Paddock CD, Curns AT, et al. Analysis of risk factors for fatal Rocky Mountain spotted fever: evidence for superiority of tetracyclines for therapy. J Infect Dis. 2001;184:1437-1444.http://jid.oxfordjournals.org/content/184/11/1437.longhttp://www.ncbi.nlm.nih.gov/pubmed/11709786?tool=bestpractice.com[19]Kirkland KB, Wilkinson WE, Sexton DJ. Therapeutic delay and mortality in cases of Rocky Mountain spotted fever. Clin Infect Dis. 1995;20:1118-1121.http://www.ncbi.nlm.nih.gov/pubmed/7619985?tool=bestpractice.com中等质量证据还表明,死于 RMSF 的患者相比于幸存患者,开始合适抗生素治疗的时间较后者晚两天。[5]Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. J Infect Dis. 1984;150:480-488.http://www.ncbi.nlm.nih.gov/pubmed/6491365?tool=bestpractice.com[20]Hattwick MA, Retailliau H, O'Brien RJ, et al. Fatal Rocky Mountain spotted fever. JAMA. 1978;240:1499-1503.http://www.ncbi.nlm.nih.gov/pubmed/682354?tool=bestpractice.com受试者<200名的随机对照临床试验(RCT)、受试者>200名且方法学存在缺陷的随机对照临床试验(RCT)、方法学存在缺陷的系统评价或者高质量的观察性(队列)研究。
对 1999~2007 年报告的 RMSF 病例进行分析的结果发现 5~9 岁儿童、70 岁及以上成人、美洲原住民、免疫功能低下人群以及 3 月 1 日至 5 月 31 日间发病的患者死亡率增加。[21]Dahlgren FS, Holman RC, Paddock CD, et al. Fatal Rocky Mountain spotted fever in the United States, 1999-2007. Am J Trop Med Hyg. 2012;86:713-719.http://www.ajtmh.org/content/86/4/713.longhttp://www.ncbi.nlm.nih.gov/pubmed/22492159?tool=bestpractice.com既往研究也认为死亡可能与导致延迟(或遗漏)治疗等因素有关(如未知身体曾有蜱虫附着);[5]Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. J Infect Dis. 1984;150:480-488.http://www.ncbi.nlm.nih.gov/pubmed/6491365?tool=bestpractice.com[17]Holman RC, Paddock CD, Curns AT, et al. Analysis of risk factors for fatal Rocky Mountain spotted fever: evidence for superiority of tetracyclines for therapy. J Infect Dis. 2001;184:1437-1444.http://jid.oxfordjournals.org/content/184/11/1437.longhttp://www.ncbi.nlm.nih.gov/pubmed/11709786?tool=bestpractice.com未伴头痛症状;[17]Holman RC, Paddock CD, Curns AT, et al. Analysis of risk factors for fatal Rocky Mountain spotted fever: evidence for superiority of tetracyclines for therapy. J Infect Dis. 2001;184:1437-1444.http://jid.oxfordjournals.org/content/184/11/1437.longhttp://www.ncbi.nlm.nih.gov/pubmed/11709786?tool=bestpractice.com皮疹出现延迟或未及时识别出皮疹;[5]Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. J Infect Dis. 1984;150:480-488.http://www.ncbi.nlm.nih.gov/pubmed/6491365?tool=bestpractice.com[20]Hattwick MA, Retailliau H, O'Brien RJ, et al. Fatal Rocky Mountain spotted fever. JAMA. 1978;240:1499-1503.http://www.ncbi.nlm.nih.gov/pubmed/682354?tool=bestpractice.com除发热、皮疹或头痛外的初始症状。[5]Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. J Infect Dis. 1984;150:480-488.http://www.ncbi.nlm.nih.gov/pubmed/6491365?tool=bestpractice.com
发病率
大约 10%~15% 的存活患者出院时伴有后遗症,某些病例是永久性的神经功能障碍。[1]Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States. MMWR Recomm Rep. 2016;65:1-44.http://www.cdc.gov/mmwr/volumes/65/rr/rr6502a1.htmhttp://www.ncbi.nlm.nih.gov/pubmed/27172113?tool=bestpractice.com神经系统并发症包括认知障碍、轻瘫、听力受损、失明、神经病变和脑皮质功能异常。非神经系统后遗症较为少见,大部分与皮肤坏死相关,受损皮肤可能需要进行植皮手术,受损四肢或手指(脚趾)可能需要截肢。[1]Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever and other spotted fever group rickettsioses, ehrlichioses, and anaplasmosis - United States. MMWR Recomm Rep. 2016;65:1-44.http://www.cdc.gov/mmwr/volumes/65/rr/rr6502a1.htmhttp://www.ncbi.nlm.nih.gov/pubmed/27172113?tool=bestpractice.com[6]Buckingham SC, Marshall GS, Schutze GE, et al. Clinical and laboratory features, hospital course, and outcome of Rocky Mountain spotted fever in children. J Pediatr. 2007;150:180-184.http://www.ncbi.nlm.nih.gov/pubmed/17236897?tool=bestpractice.com[22]Archibald LK, Sexton DJ. Long-term sequelae of Rocky Mountain spotted fever. Clin Infect Dis. 1995;20:1122-1125.http://www.ncbi.nlm.nih.gov/pubmed/7619986?tool=bestpractice.com对儿童来说,神经系统不良治疗效果的独立危险因素包括昏迷、需要流体饮食和/或强心剂治疗。[6]Buckingham SC, Marshall GS, Schutze GE, et al. Clinical and laboratory features, hospital course, and outcome of Rocky Mountain spotted fever in children. J Pediatr. 2007;150:180-184.http://www.ncbi.nlm.nih.gov/pubmed/17236897?tool=bestpractice.com