宏基因组二代测序诊断鹦鹉热衣原体肺炎4例

An analysis of four cases with Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation sequencing

目的 分析4例鹦鹉热衣原体肺炎患者的临床特征及诊治思路,探讨宏基因组二代测序(mNGS)在鹦鹉热衣原体肺炎诊断中的应用价值。方法 回顾性分析4例鹦鹉热衣原体肺炎患者的临床资料。入院后进行实验室、影像学及支气管镜检查,并进行肺泡灌洗液mNGS检测。观察治疗后临床结局。结果 患者发病前均有明确的鸟类或禽类接触史,以发热、咳嗽为首要临床表现,可见头晕、呼吸困难及肌肉酸痛等表现。4例患者白细胞计数未见明显升高,淋巴细胞计数、血钠下降,CRP、降钙素原、铁蛋白、纤维蛋白原和D-二聚体明显升高,AST及乳酸脱氢酶升高。胸部CT显示肺间质性病变3例,双侧胸腔积液2例。肺泡灌洗液mNGS检测显示,4例患者均查出鹦鹉热衣原体序列,及时调整为以多西环素为基础的治疗方案,其中1例患者合并真菌感染,联合使用氟康唑抗真菌治疗,均好转出院。结论 鹦鹉热衣原体肺炎起病急,多见发热、咳嗽,禽类和鸟类接触史为重要诊断线索,临床症状及实验室、影像学检查缺乏特异性。肺泡灌洗液mNGS检测能够快速明确诊断,减少漏诊、误诊。以多西环素为基础的治疗效果明显,患者如合并其他病菌感染,需要联合用药治疗。

Objective To analyze the clinical characteristics and diagnosis of 4 patients with Chlamydia psittaci pneumonia, and investigate the application value of metagenomic next-generation sequencing(mNGS) in the diagnosis of Chlamydia psittaci pneumonia.Methods The clinical data of 4 patients with Chlamydia psittaci pneumonia were retrospectively analyzed.The laboratory test, imaging examination and bronchoscopy were performed after admission, and the mNGS in alveolar lavage fluid was proceeded.The clinical outcomes were observed after treatment.ResultsAll the patients had a history of exposure to birds or poultry before onset.The fever and cough were the primary clinical manifestations accompanied with dizziness, dyspnea and muscle soreness.The laboratory test showed that the white blood cell count was not obviously increased, lymphocyte count and serum sodium were decreased, CRP,procalcitonin, ferritin, fibrinogen and D-dimer were significantly increased, and AST and lactic dehydrogenase were increased.The imaging examination showed that the pulmonary interstitial pneumonia was seen in 3 cases and the bilateral pleural effusion occurred in 2 cases.The sequence of Chlamydia psittaci could be detected by mNGS in the alveolar lavage fluid, which was adjusted to doxycycline-based treatment plan in time.One case was treated with fluconazole because of fungal infection.All the patients were discharged after the illness was improved.Conclusion The onset of Chlamydia psittaci pneumonia is rapid accompanied by fever and cough.The contact history of poultry or birds is an important diagnostic clue.The clinical manifestation, laboratory test and imaging examination are not specific.The mNGS in the alveolar lavage fluid can be used to diagnose the disease quickly and reduce the missed diagnosis and misdiagnosis.Doxycycline-based treatment is effective in the patients with Chlamydia psittaci pneumonia, and the combination therapy is needed in those severe patients with other pathogenic bacterial infection.