Clinical, laboratory and radiologic characteristics of 2009 pandemic influenza A/H1N1 pneumonia: Primary influenza pneumonia versus concomitant/secondary bacterial pneumonia

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Abstract

Background 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. Methods From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15years) 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. Results 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 0·35ng/ml, sensitivity 81·8%, and specificity 66·7%) and CRP (cutoff value 86·5mg/IU, sensitivity 81·8%, and specificity 59·3%) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia. Conclusions 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.

Original languageEnglish
JournalInfluenza and other Respiratory Viruses
Volume5
Issue number6
DOIs
Publication statusPublished - 2011 Nov 1

Fingerprint

Bacterial Pneumonia
Pandemics
Human Influenza
Pneumonia
Calcitonin
C-Reactive Protein
Lung
Sensitivity and Specificity
Myalgia
Respiratory Sounds
Korea
Orthomyxoviridae
L-Lactate Dehydrogenase
Nose
Respiratory System
Headache
Case-Control Studies
Diarrhea

Keywords

  • 2009 H1N1
  • C-reactive protein
  • Influenza
  • Pneumonia
  • Procalcitonin

ASJC Scopus subject areas

  • Infectious Diseases
  • Pulmonary and Respiratory Medicine
  • Public Health, Environmental and Occupational Health
  • Epidemiology

Cite this

@article{14846361dfeb44f3b97873d1dcff47b8,
title = "Clinical, laboratory and radiologic characteristics of 2009 pandemic influenza A/H1N1 pneumonia: Primary influenza pneumonia versus concomitant/secondary bacterial pneumonia",
abstract = "Background 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. Methods From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15years) 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. Results 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 0·35ng/ml, sensitivity 81·8{\%}, and specificity 66·7{\%}) and CRP (cutoff value 86·5mg/IU, sensitivity 81·8{\%}, and specificity 59·3{\%}) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia. Conclusions 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.",
keywords = "2009 H1N1, C-reactive protein, Influenza, Pneumonia, Procalcitonin",
author = "Joon-Young Song and Hee-Jin Cheong and Heo, {Jung Y.} and Noh, {Ji Yun} and Hwan-Seok Yong and Kim, {Yoon K.} and Eun-Young Kang and Wonseok Choi and Jo, {Yu M.} and Kim, {Woo Joo}",
year = "2011",
month = "11",
day = "1",
doi = "10.1111/j.1750-2659.2011.00269.x",
language = "English",
volume = "5",
journal = "Influenza and other Respiratory Viruses",
issn = "1750-2640",
publisher = "Wiley-Blackwell",
number = "6",

}

TY - JOUR

T1 - Clinical, laboratory and radiologic characteristics of 2009 pandemic influenza A/H1N1 pneumonia

T2 - Primary influenza pneumonia versus concomitant/secondary bacterial pneumonia

AU - Song, Joon-Young

AU - Cheong, Hee-Jin

AU - Heo, Jung Y.

AU - Noh, Ji Yun

AU - Yong, Hwan-Seok

AU - Kim, Yoon K.

AU - Kang, Eun-Young

AU - Choi, Wonseok

AU - Jo, Yu M.

AU - Kim, Woo Joo

PY - 2011/11/1

Y1 - 2011/11/1

N2 - Background 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. Methods From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15years) 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. Results 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 0·35ng/ml, sensitivity 81·8%, and specificity 66·7%) and CRP (cutoff value 86·5mg/IU, sensitivity 81·8%, and specificity 59·3%) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia. Conclusions 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.

AB - Background 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. Methods From September 1, 2009, to January 31, 2010, a specialized clinic for patients (aged ≥15years) 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. Results 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 0·35ng/ml, sensitivity 81·8%, and specificity 66·7%) and CRP (cutoff value 86·5mg/IU, sensitivity 81·8%, and specificity 59·3%) were discriminative between patients with concomitant/secondary bacterial pneumonia and patients with primary influenza pneumonia. Conclusions 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.

KW - 2009 H1N1

KW - C-reactive protein

KW - Influenza

KW - Pneumonia

KW - Procalcitonin

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U2 - 10.1111/j.1750-2659.2011.00269.x

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