Nausheen Sara, Cunha Burke A
Infectious Disease Division, Winthrop-University Hospital, Mineola, NY 11501, USA.
Heart Lung. 2007 Jul-Aug;36(4):300-3. doi: 10.1016/j.hrtlng.2007.02.010.
Community-acquired pneumonia (CAP) may be caused by typical or atypical pathogens. The three most common zoonotic atypical pathogens are Chlamydophila psittaci (psittacosis), Francisella tularensis (tularemia), and Coxiella burnetii (Q fever). Atypical CAPs are suggested by a distinctive pattern of extrapulmonary organ involvement. Zoonotic CAP may be differentiated from nonzoonotic CAP (Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionnaire's disease) by a recent zoonotic vector contact history. Zoonotic atypical CAP occurs sporadically, but not randomly, and require close association with the appropriate zoonotic vector to transmit the infection. CAP accompanied by the extrapulmonary finding of splenomegaly in a normal host limits differential diagnostic possibilities to Q fever and psittacosis. Splenomegaly does not occur with other typical or atypical CAP. Another common extrapulmonary finding occurs with some atypical pneumonias, that is, Q fever, psittacosis, and Legionnaire's disease is early mild/transient elevations of serum transaminases indicative of (hepatic) extrapulmonary organ involvement. The case presented is a middle-aged man with longstanding Crohn's disease who was further immunosuppressed by chronic prednisone therapy. The patient presented with CAP and extrapulmonary findings, that is, splenomegaly and increased serum transaminases. He denied recent contact with birds or animals. Because Crohn's disease and Q fever CAP may be accompanied by splenomegaly, the cause of his splenomegaly was a diagnostic dilemma. The patient was treated with levofloxacin. Serologic tests for atypical pathogens (Q fever, psittacosis, Legionnaire's disease, C. pneumoniae, and M. pneumoniae) were ordered. Enzyme-linked immunosorbent assay serology for Q fever was positive with elevated acute immunoglobulin-M (phase II) titers. Re-questioning of the patient revealed a recent exposure to a neighbor's parturient cat, providing the necessary zoonotic vector contact history for Q fever. The patient responded to levofloxacin, which resulted in resolution of the patient's symptoms, right lower lobe pneumonia, and splenomegaly. Because a prior abdominal computed tomography scan indicated no splenomegaly and his splenomegaly resolved with antimicrobial therapy, the splenomegaly was related to Q fever CAP.
社区获得性肺炎（CAP）可能由典型或非典型病原体引起。三种最常见的人畜共患非典型病原体是鹦鹉热衣原体（鹦鹉热）、土拉弗朗西斯菌（兔热病）和伯氏考克斯体（Q热）。肺外器官受累的独特模式提示为非典型CAP。人畜共患CAP可通过近期的人畜共患病原体接触史与非人畜共患CAP（肺炎衣原体、肺炎支原体、军团病）相鉴别。人畜共患非典型CAP呈散发性，但并非随机发生，需要与相应的人畜共患病原体密切接触才能传播感染。在正常宿主中，伴有脾肿大这一肺外表现的CAP将鉴别诊断范围局限于Q热和鹦鹉热。其他典型或非典型CAP不会出现脾肿大。一些非典型肺炎还会出现另一种常见的肺外表现，即Q热、鹦鹉热和军团病会出现血清转氨酶早期轻度/短暂升高，提示（肝脏）肺外器官受累。本文介绍的病例是一名患有长期克罗恩病的中年男子，长期使用泼尼松治疗使其免疫功能进一步受到抑制。该患者表现为CAP及肺外表现，即脾肿大和血清转氨酶升高。他否认近期接触过鸟类或动物。由于克罗恩病和Q热CAP可能伴有脾肿大，其脾肿大的原因成为诊断难题。该患者接受了左氧氟沙星治疗。对非典型病原体（Q热、鹦鹉热、军团病、肺炎衣原体和肺炎支原体）进行了血清学检测。Q热的酶联免疫吸附试验血清学检测呈阳性，急性免疫球蛋白M（II期）滴度升高。再次询问患者发现其近期接触过邻居的产仔猫，这提供了Q热所需的人畜共患病原体接触史。患者对左氧氟沙星治疗有反应，症状、右下叶肺炎和脾肿大均得到缓解。由于之前的腹部计算机断层扫描显示没有脾肿大，且其脾肿大在抗菌治疗后消退，所以脾肿大与Q热CAP有关。
