卡氏肺囊虫性肺炎

肺门部可出现典型的网状或颗粒状影，可从肺门部扩散。[Figure caption and citation for the preceding image starts]: 胸部X线显示两肺轻度网状样间质浸润图片由Matthew Gingo（UPMC）提供 [Citation ends].其很少不对称或进展为网状肺泡影。

胸部X线表现多样，包括大叶实变、结节性病变、气胸、纵隔气肿，甚至正常。也可有肺囊肿或肺大泡。[82]Kennedy CA, Goetz MB. Atypical roentgenographic manifestations of Pneumocystis carinii pneumonia. Arch Intern Med. 1992;152:1390-1398.http://www.ncbi.nlm.nih.gov/pubmed/1627019?tool=bestpractice.com[83]Sandhu JS, Goodman PC. Pulmonary cysts associated with Pneumocystis carinii pneumonia in patients with AIDS. Radiology. 1989;173:33-35.http://www.ncbi.nlm.nih.gov/pubmed/2789413?tool=bestpractice.com[Figure caption and citation for the preceding image starts]: 胸部X线表现为两肺严重的间质浸润伴有肺囊肿图片由Matthew Gingo（UPMC）提供 [Citation ends].

胸腔积液或淋巴结肿大建议替代的诊断

为预防卡氏肺孢子虫肺炎（PCP）而使用吸入喷他脒的患者，胸部X线可出现以肺部右上叶为主的浸润。[84]Abd AG, Nierman DM, Ilowite JS, et al. Bilateral upper lobe Pneumocystis carinii pneumonia in a patient receiving inhaled pentamidine prophylaxis. Chest. 1988 Aug;94(2):329-31.http://journal.chestnet.org/article/S0012-3692(16)33453-5/fulltexthttp://www.ncbi.nlm.nih.gov/pubmed/3260848?tool=bestpractice.com

双侧对称性间质侵润

室内空气状态下，当pO2＜70mmHg或肺泡-动脉(A-a)氧分压差＞35时，认为疾病进展至中度到重度。

pO2减少和A-a梯度增加

90%感染HIV的PCP患者LDH水平升高。治疗成功后LDH水平下降。[60]Zaman MK, White DA. Serum lactate dehydrogenase levels and Pneumocystis carinii pneumonia. Diagnostic and prognostic significance. Lancet. 1988 Nov 5;2(8619):1049-51.http://www.ncbi.nlm.nih.gov/pubmed/3258483?tool=bestpractice.com

升高(＞220IU/L)

应诱导咳痰，送至能够提供最佳检查的机构通过此法行金罗维氏肺囊虫染色。[Figure caption and citation for the preceding image starts]: 支气管肺泡灌洗（BAL）液显微照片示肺孢子虫包囊，Grocott-Gomori氏六胺银改良法染色呈黑色（甲基绿复染）图片由Matthew Gingo（UPMC）提供 [Citation ends].

诱导痰检测的敏感性取决于标本质量、应用的染色技术和实验室经验，敏感性约50%-90%。[43]Centers for Disease Control and Prevention; National Institutes of Health; HIV Medicine Association of the Infectious Diseases Society of America. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. May 2016. http://aidsinfo.nih.gov/guidelines (last accessed 5 June 2016).http://aidsinfo.nih.gov/contentfiles/lvguidelines/adult_oi.pdf[55]Fortun J, Navas E, Marti-Belda P, et al. Pneumocystis carinii pneumonia in HIV-infected patients: diagnostic yield of induced sputum and immunofluorescent stain with monoclonal antibodies. Eur Respir J. 1992;5:665-669.http://www.ncbi.nlm.nih.gov/pubmed/1628723?tool=bestpractice.com[56]Kovacs JA, Ng VL, Masur H, et al. Diagnosis of Pneumocystis carinii pneumonia: improved detection in sputum with use of monoclonal antibodies. N Engl J Med. 1988;318:589-593.http://www.ncbi.nlm.nih.gov/pubmed/2449613?tool=bestpractice.com[57]Midgley J, Parsons P, Leigh TR, et al. Increased sensitivity of immunofluorescence for detection of Pneumocystis carinii. Lancet. 1989;2:1523.http://www.ncbi.nlm.nih.gov/pubmed/2574793?tool=bestpractice.com[58]Ng VL, Virani NA, Chaisson RE, et al. Rapid detection of Pneumocystis carinii using a direct fluorescent monoclonal antibody stain. J Clin Microbiol. 1990;28:2228-2233.http://www.ncbi.nlm.nih.gov/pubmed/1699968?tool=bestpractice.com

咳出痰标本灵敏度差，不应使用。

首选直接荧光抗原检测，因为其敏感性和特异性更高。

卡氏肺孢子虫阳性

患者有PCP的临床表现但无胸片的改变或胸片正常，应该做胸部HRCT，[Figure caption and citation for the preceding image starts]: 胸部CT扫描显示两肺间质性浸润和肺囊肿，这是典型的卡氏肺孢子虫肺炎(PCP)表现图片由Matthew Gingo（UPMC）提供 [Citation ends].或是通过测定一氧化碳扩散功能检测肺功能。

如果HRCT显示毛玻璃样变，患者可进一步行痰诱导检查，如果痰诱导阴性，可行BAL。 尽管CT显示毛玻璃样变对诊断具有敏感性，但并不是PCP的特异性检查。[61]Gruden JF, Huang L, Turner J, et al. High-resolution CT in the evaluation of clinically suspected Pneumocystis carinii pneumonia in AIDS patients with normal, equivocal, or nonspecific radiographic findings. AJR Am J Roentgenol. 1997;169:967-975.http://www.ajronline.org/doi/pdf/10.2214/ajr.169.4.9308446http://www.ncbi.nlm.nih.gov/pubmed/9308446?tool=bestpractice.com[62]Huang L, Stansell J, Osmond D, et al. Performance of an algorithm to detect Pneumocystis carinii pneumonia in symptomatic HIV-infected persons. Chest. 1999 Apr;115(4):1025-32.http://journal.chestnet.org/article/S0012-3692(16)37737-6/fulltexthttp://www.ncbi.nlm.nih.gov/pubmed/10208204?tool=bestpractice.com[63]Sankary RM, Turner J, Lipavsky A, et al. Alveolar-capillary block in patients with AIDS and Pneumocystis carinii pneumonia. Am Rev Respir Dis. 1988;137:443-449.http://www.ncbi.nlm.nih.gov/pubmed/3257662?tool=bestpractice.com

PCP患者HRCT无殊几乎不可能。[61]Gruden JF, Huang L, Turner J, et al. High-resolution CT in the evaluation of clinically suspected Pneumocystis carinii pneumonia in AIDS patients with normal, equivocal, or nonspecific radiographic findings. AJR Am J Roentgenol. 1997;169:967-975.http://www.ajronline.org/doi/pdf/10.2214/ajr.169.4.9308446http://www.ncbi.nlm.nih.gov/pubmed/9308446?tool=bestpractice.com

两肺弥漫性磨玻璃样影

患者有PCP的临床表现但无胸片的改变或胸片正常，应该测定一氧化碳扩散功能（DLCO）或进行胸部HRCT。

如果DLCO下降，患者可进一步行痰诱导检查，如果痰诱导阴性，可行BAL。 尽管DLCO对诊断具有敏感性，但并不是PCP的特异性检查。[61]Gruden JF, Huang L, Turner J, et al. High-resolution CT in the evaluation of clinically suspected Pneumocystis carinii pneumonia in AIDS patients with normal, equivocal, or nonspecific radiographic findings. AJR Am J Roentgenol. 1997;169:967-975.http://www.ajronline.org/doi/pdf/10.2214/ajr.169.4.9308446http://www.ncbi.nlm.nih.gov/pubmed/9308446?tool=bestpractice.com[62]Huang L, Stansell J, Osmond D, et al. Performance of an algorithm to detect Pneumocystis carinii pneumonia in symptomatic HIV-infected persons. Chest. 1999 Apr;115(4):1025-32.http://journal.chestnet.org/article/S0012-3692(16)37737-6/fulltexthttp://www.ncbi.nlm.nih.gov/pubmed/10208204?tool=bestpractice.com[63]Sankary RM, Turner J, Lipavsky A, et al. Alveolar-capillary block in patients with AIDS and Pneumocystis carinii pneumonia. Am Rev Respir Dis. 1988;137:443-449.http://www.ncbi.nlm.nih.gov/pubmed/3257662?tool=bestpractice.com

诊断PCP的患者很少DLCO正常。如果患者DLCO低（＜80%预测值），应进行痰诱导检查。

一氧化碳扩散功能（DLCO）下降

如果痰诱导阴性，可行支气管镜检查和BAL。

肺泡灌洗液应该送组织染色。

HIV阳性患者的支气管肺泡灌洗灵敏度约90%-99%。[43]Centers for Disease Control and Prevention; National Institutes of Health; HIV Medicine Association of the Infectious Diseases Society of America. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. May 2016. http://aidsinfo.nih.gov/guidelines (last accessed 5 June 2016).http://aidsinfo.nih.gov/contentfiles/lvguidelines/adult_oi.pdf对于HIV阴性患者单独行支气管肺泡灌洗检查灵敏度不高。

卡氏肺孢子虫阳性

HIV阴性的患者由于BAL敏感性低，往往需经纤维支气管镜活检确认诊断。

经纤维支气管镜活检的灵敏度约95%-100%。[43]Centers for Disease Control and Prevention; National Institutes of Health; HIV Medicine Association of the Infectious Diseases Society of America. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. May 2016. http://aidsinfo.nih.gov/guidelines (last accessed 5 June 2016).http://aidsinfo.nih.gov/contentfiles/lvguidelines/adult_oi.pdf

如果临床高度怀疑PCP且之前检查无法确定病因，可行开放性肺活检明确PCP或其他疾病是否存在。

卡氏肺孢子虫阳性

PCR、荧光定量PCR和逆转录聚合酶链反应可以检测到低水平的耶氏肺孢子虫DNA。

以上检测和S-腺苷蛋氨酸的血浆水平可提高PCP的诊断率，但临床上不常使用。PCR较组织化学染色有较高的假阳性率。[66]Fillaux J, Malvy S, Alvarez M, et al. Accuracy of a routine real-time PCR assay for the diagnosis of Pneumocystis jiroveci pneumonia. J Microbiol Methods. 2008;75:258-261.http://www.ncbi.nlm.nih.gov/pubmed/18606198?tool=bestpractice.com[67]Tuncer S, Erguven S, Kocagoz S, et al. Comparison of cytochemical staining, immunofluorescence and PCR for diagnosis of Pneumocystis carinii on sputum samples. Scand J Infect Dis. 1998;30:125-128.http://www.ncbi.nlm.nih.gov/pubmed/9730296?tool=bestpractice.com[68]Larsen HH, Masur H, Kovacs JA, et al. Development and evaluation of a quantitative, touch-down, real-time PCR assay for diagnosing Pneumocystis carinii pneumonia. J Clin Microbiol. 2002;40:490-494.http://www.ncbi.nlm.nih.gov/pubmed/11825961?tool=bestpractice.com[69]Helweg-Larsen J, Jensen JS, Lundgren B. Diagnostic use of PCR for detection of Pneumocystis carinii in oral wash samples. J Clin Microbiol. 1998;36:2068-2072.http://www.ncbi.nlm.nih.gov/pubmed/9650964?tool=bestpractice.com[70]Larsen HH, Huang L, Kovacs JA, et al. A prospective, blinded study of quantitative touch-down polymerase chain reaction using oral-wash samples for diagnosis of Pneumocystis pneumonia in HIV-infected patients. J Infect Dis. 2004;189:1679-1683.http://www.ncbi.nlm.nih.gov/pubmed/15116305?tool=bestpractice.com[72]Summah H, Zhu YG, Falagas ME, et al. Use of real-time polymerase chain reaction for the diagnosis of Pneumocystis pneumonia in immunocompromised patients: a meta-analysis. Chin Med J (Engl). 2013;126:1965-1973.http://www.ncbi.nlm.nih.gov/pubmed/23673119?tool=bestpractice.com

卡氏肺孢子虫阳性

可能会增加诊断PCP的敏感性，但目前未应用于临床。[71]Skelly MJ, Holzman RS, Merali S. S-adenosylmethionine levels in the diagnosis of Pneumocystis carinii pneumonia in patients with HIV infection. Clin Infect Dis. 2008;46:467-471.http://cid.oxfordjournals.org/content/46/3/467.longhttp://www.ncbi.nlm.nih.gov/pubmed/18177224?tool=bestpractice.com

下降

检测血清 (1,3)-β-D-葡聚糖（真菌细胞壁的组成元素）对PCP的诊断也有意义。[73]Watanabe T, Yasuoka A, Tanuma J, et al. Serum (1-->3) beta-D-glucan as a noninvasive adjunct marker for the diagnosis of Pneumocystis pneumonia in patients with AIDS. Clin Infect Dis. 2009;49:1128-1131.http://cid.oxfordjournals.org/content/49/7/1128.longhttp://www.ncbi.nlm.nih.gov/pubmed/19725788?tool=bestpractice.com[74]Shimizu Y, Sunaga N, Dobashi K, et al. Serum markers in interstitial pneumonia with and without Pneumocystis jirovecii colonization: a prospective study. BMC Infect Dis. 2009;9:47.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2676289/?tool=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19383170?tool=bestpractice.com[75]Desmet S, Van Wijngaerden E, Maertens J, et al. Serum (1-3)-beta-D-glucan as a tool for diagnosis of Pneumocystis jirovecii pneumonia in patients with human immunodeficiency virus infection or hematological malignancy. J Clin Microbiol. 2009;47:3871-3874.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2786638/?tool=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19846641?tool=bestpractice.com[76]Del Bono V, Mularoni A, Furfaro E, et al. Clinical evaluation of a (1,3)-beta-D-glucan assay for presumptive diagnosis of Pneumocystis jiroveci pneumonia in immunocompromised patients. Clin Vaccine Immunol. 2009;16:1524-1526.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2756857/?tool=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19692624?tool=bestpractice.com[77]Nakamura H, Tateyama M, Tasato D, et al. Clinical utility of serum beta-D-glucan and KL-6 levels in Pneumocystis jirovecii pneumonia. Intern Med. 2009;48:195-202.https://www.jstage.jst.go.jp/article/internalmedicine/48/4/48_4_195/_articlehttp://www.ncbi.nlm.nih.gov/pubmed/19218768?tool=bestpractice.com

有研究显示 PCP 患者血清 (1,3)-β-D-葡聚糖水平明显升高，但在 HIV 阴性 PCP 患者中减少，其水平高低与病情严重性和治疗反应无关联。[78]Huang L. Clinical and translational research in pneumocystis and pneumocystis pneumonia. Parasite. 2011;18:3-11.http://www.ncbi.nlm.nih.gov/pubmed/21395200?tool=bestpractice.com

此外，在一项包括159位AIDS患者研究中，每位患者至少有一种呼吸道症状，其中139位患有PCP，β-葡聚糖（≥80 ng/ml）的敏感性和特异性分别为92.8%和75.0%。[81]Wood BR, Komarow L, Zolopa AR, et al. Test performance of blood beta-glucan for Pneumocystis jirovecii pneumonia in patients with AIDS and respiratory symptoms. AIDS. 2013;27:967-972.http://www.ncbi.nlm.nih.gov/pubmed/23698062?tool=bestpractice.com

每个测试的特点都需要与相应的对照组进行大量的研究，因为其他真菌感染也可能存在该标记物的升高。

升高