Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
Influenza Other Respir Viruses. 2011 Nov;5(6):e535-43. doi: 10.1111/j.1750-2659.2011.00269.x. Epub 2011 Jun 20.
Although influenza virus usually involves the upper respiratory tract, pneumonia was seen more frequently with the 2009 pandemic influenza A/H1N1 than with seasonal influenza.
From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15 years) with ILI was operated in Korea University Guro Hospital. RT-PCR assay was performed to diagnose 2009 pandemic influenza A/H1N1. A retrospective case-case-control study was performed to determine the predictive factors for influenza pneumonia and to discriminate concomitant/secondary bacterial pneumonia from primary influenza pneumonia during the 2009-2010 pandemic.
During the study period, the proportions of fatal cases and pneumonia development were 0·12% and 1·59%, respectively. Patients with pneumonic influenza were less likely to have nasal symptoms and extra-pulmonary symptoms (myalgia, headache, and diarrhea) compared to patients with non-pneumonic influenza. Crackle was audible in just about half of the patients with pneumonic influenza (38·5% of patients with primary influenza pneumonia and 53·3% of patients with concomitant/secondary bacterial pneumonia). Procalcitonin, C-reactive protein (CRP), and lactate dehydrogenase were markedly increased in patients with influenza pneumonia. Furthermore, procalcitonin (cutoff value 0·35 ng/ml, sensitivity 81·8%, and specificity 66·7%) and CRP (cutoff value 86·5 mg/IU, sensitivity 81·8%, and specificity 59·3%) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia.
Considering the subtle manifestations of 2009 pandemic influenza A/H1N1 pneumonia in the early stage, high clinical suspicion is required to detect this condition. Both procalcitonin and CRP would be helpful to differentiate primary influenza pneumonia from concomitant/secondary bacterial pneumonia.
虽然流感病毒通常涉及上呼吸道，但与季节性流感相比，2009 年甲型 H1N1 流感大流行时更常出现肺炎。
从 2009 年 9 月 1 日至 2010 年 1 月 31 日，韩国大学古罗医院开设了一个专门为 ILI 患者（年龄≥15 岁）服务的诊所。采用 RT-PCR 检测诊断 2009 年甲型 H1N1 流感大流行。进行回顾性病例对照研究，以确定流感肺炎的预测因素，并在 2009-2010 年大流行期间区分合并/继发细菌性肺炎与原发性流感肺炎。
在研究期间，死亡病例和肺炎发展的比例分别为 0.12%和 1.59%。与非肺炎型流感患者相比，肺炎型流感患者更不可能出现鼻部症状和肺外症状（肌痛、头痛和腹泻）。约一半的肺炎型流感患者可闻及爆裂音（原发性流感肺炎患者为 38.5%，合并/继发细菌性肺炎患者为 53.3%）。流感肺炎患者降钙素原、C 反应蛋白（CRP）和乳酸脱氢酶显著升高。此外，降钙素原（截断值 0.35ng/ml，灵敏度 81.8%，特异性 66.7%）和 CRP（截断值 86.5mg/ IU，灵敏度 81.8%，特异性 59.3%）有助于区分合并/继发细菌性肺炎和原发性流感肺炎患者。
考虑到 2009 年甲型 H1N1 流感肺炎在早期的细微表现，需要高度的临床怀疑来检测这种情况。降钙素原和 CRP 均有助于区分原发性流感肺炎和合并/继发细菌性肺炎。
