The 2009 pandemic influenza A(H1N1) virus damages the entire airway, from the trachea to the alveoli of the lungs, according to the results of 34 autopsies.

All of the autopsies showed evidence of focal or extensive tracheitis and bronchitis, wrote Dr. James R. Gill of the New York City Office of Chief Medical Examiner and his colleagues in a paper published online Dec. 7 in the journal Archives of Pathology and Laboratory Medicine. The article will appear in the February 2010 print issue (Arch. Pathol. Lab. Med. 2010;134:e1-9).

In 18 of the 34 cases, investigators observed focal mild to moderate bronchiolitis. In 25 cases, investigators observed focal to extensive diffuse alveolar damage from influenza viral pneumonia. Investigators found evidence of acute bacterial pneumonia in 18 patients; 16 of those patients had streptococci, and 2 patients had staphylococci. Eight of the autopsies revealed acute pulmonary hemorrhage.

“These pathologic findings are strikingly similar to those of published autopsy studies from the 1918 and 1957 pandemics and to a more limited extent from publications investigating seasonal influenza,” the investigators wrote.

Victims of seasonal influenza tend to have much less evidence of viral replication in the lung than do victims of the influenza pandemics, including the pandemic resulting from this year’s H1N1 virus, said coauthor Dr. Jeffery K. Taubenberger of the U.S. National Institute of Allergy and Infectious Diseases (NIAID) in an interview.

Autopsies from victims of the pandemics show much more evidence of serious viral pneumonia, he added, whereas victims of seasonal influenza are more likely to have bacterial pneumonia.

Investigators obtained CT scans from four of the victims. All four showed a distinctive abnormality called ground-glass opacity. “Our findings suggest that CT can be a valuable tool in identifying patients who will require intensive medical support and to elucidate the pathogenesis of severe disease,” the investigators wrote.

The patients involved in the study ranged in age from 2 months to 72 years (median, 41.5 years), and they died between May 15 and July 9, 2009. All had confirmed infections with pandemic H1N1 influenza virus.

Except for two healthy infants aged 2 months and 4 months, all the patients had one or more medical conditions that may have predisposed them to serious complications from H1N1 influenza. The most common comorbidities were obesity, heart disease, and underlying pulmonary disease.

The U.S. National Institutes of Health supported the study in part through NIAID. Some of the investigators were NIAID employees. The investigators stated that they had no financial conflicts related to the study.

Copyright (c) 2009 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

34例尸检结果显示，2009年大流行性甲型流感(H1N1)病毒可造成从气管到肺泡的全气道损害。

 

纽约市法医鉴定局James R. Gill博士及其同事于12月7日在线发表于《病理学和实验室医学档案》(Archives of Pathology and Laboratory Medicine)杂志的报告称，所有尸检均有局灶或广泛分布的气管和支气管炎。本文将于2010年2月刊登在纸质版杂志上 (Arch. Pathol. Lab. Med. 2010;134:e1-9)。

 

研究者发现上述34例患者中有18例出现轻中度局灶性支气管炎；25例出现流感病毒性肺炎造成的局灶或广泛弥漫性肺泡损伤。此外，研究者在18例患者身上发现了急性细菌性肺炎的证据，其中16例为链球菌感染，另外2例为葡萄球菌。尸检病例中有8例被检出有急性肺出血。

 

“这些病理学发现与1918年和1957年流感大流行时出版的尸检结果惊人地相似，与季节性流感的研究报道的相似度则比较有限，”研究者写道。

 

美国国家过敏及传染性疾病研究所(NIAID)的Jeffery K. Taubenberger博士在一次采访中表示，在季节性流感患者肺内，病毒复制的证据要明显少于流感大流行受累患者，包括今年H1N1型病毒造成大流行。

 

他补充道，在大流行性流感受累患者的尸检中，严重病毒性肺炎的证据更为多见，相比之下，季节性流感患者则更易罹患细菌性肺炎。

 

研究者们获得了4例患者的CT扫描结果，发现4例均具有一种特征性异常改变，称为“毛玻璃样”。研究者写道：“我们的发现表明，在鉴别需要重症监护的患者并阐明严重疾病的发病机理方面，CT可能是一种有价值的工具。”

 

本项研究中尸检病例的年龄范围为2个月至72岁(中位年龄41.5岁)，死亡时间在今年5月15日至7月9日之间。所有病例均已被证实感染此次大流行的H1N1流感病毒。

 

除2月龄和4月龄的两名健康婴儿外，所有患者均有至少一项可能导致H1N1流感严重并发症的医学疾病。最常见的合并症为肥胖、心脏病和潜在的肺部疾病。

 

美国国立卫生研究院通过NIAID部分资助本研究。一些研究者为NIAID的雇员。研究者无与研究相关的任何经济利益冲突。

 

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