Tuberc Respir Dis.  2010 Jul;69(1):24-30.

Clinical Features of Hospitalized Adult Patients with Pneumonia in Novel Influenza A (H1N1) Infection

• Han CH
• Hyun YK
• Choi YR
• Sung NY
• Park YS
• Lee KS
• Chung JH

Abstract

BACKGROUND
A novel 2009 influenza A (H1N1) virus emerged and disseminated to all over the world. There are few reports on the clinical characteristics of patients with complications. We describe the clinical features of pneumonia in adult patients hospitalized, who have novel influenza infection.
METHODS
There were 43 adult patients enrolled into the study with pneumonia of 528 hospitalized patients confirmed influenza A (H1N1) virus infection by real-time reverse transcriptase polymerase chain reaction testing, between 24 August 2009 and 31 January 2010. The clinical data of patients with pneumonia were collected retrospectively.
RESULTS
There were 22 of 43 (51.2%) influenza patients with pneumonia that had higher risk factors for complications. Compared to 28 patients with influenza A (H1N1) viral pneumonia and 15 patients, who had isolated bacteria from cultures, those with mixed viral and bacterial pneumonia were significantly more likely to have unilobar consolidations on chest radiographs (53.3 vs. 10.7%, p<0.01) and higher scores of pneumonia severity index (PSI; 90 [66~100] vs. 53 [28~90], p=0.04). Six patients required mechanical ventilation support in an Intensive Care Unit and were more likely to have dyspnea (83.3 vs. 29.3%, p=0.02) and low levels of PaO2 (48.3 [37.0~70.5] vs 64.0 [60.0~74.5] mm Hg, p=0.02) and high levels of pneumonia severity index (PSI) score (108.0 [74.5~142.8] vs. 56.0 [40.5~91.0], p=0.03).
CONCLUSION
The majority of pneumonia patients infected with novel influenza improved. Chest radiographic findings of unilobar consolidations suggest that mixed pneumonia is more likely. Initial dyspnea, hypoxemia, and high levels of PSI score are associated with undergoing mechanical ventilation support.

Keyword

Influenza A Virus, H1N1 Subtype; Pneumonia; Disease Outbreaks

MeSH Terms

Adult
Anoxia
Bacteria
Disease Outbreaks
Dyspnea
Humans
Influenza A Virus, H1N1 Subtype
Influenza, Human
Intensive Care Units
Pneumonia
Pneumonia, Bacterial
Pneumonia, Viral
Respiration, Artificial
Retrospective Studies
Reverse Transcriptase Polymerase Chain Reaction
Risk Factors
Thorax
Viruses

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