Viral Infections in Patients With COPD
Purpose of Review: Chronic obstructive pulmonary disease is a major cause of morbidity and mortality worldwide. There is increasing evidence that implicates viral infections as a major risk factor for exacerbations of chronic obstructive pulmonary disease. Recent studies have attempted to better characterize the epidemiology of viral infections in chronic obstructive pulmonary disease, identify unique clinical manifestations of virusassociated exacerbations, and develop new diagnostic tools and treatments.
Recent Findings: Rhinovirus, the organism most often responsible for causing the common cold, is also the most common infectious cause of chronic obstructive pulmonary disease exacerbations. Coronavirus, influenza, respiratory syncytial virus, parainfluenza, adenovirus, and metapneumovirus are other important viral causes of chronic obstructive pulmonary disease exacerbations. These exacerbations can be severe with prolonged recovery times. Although PCR technology has dramatically increased the detection rate of viruses in patients with chronic obstructive pulmonary disease, it does not differentiate infection from colonization. The use of biomarkers represents an exciting new potential diagnostic tool that may lend new insights into the pathogenesis of viral infections in patients with chronic obstructive pulmonary disease.
Summary: Despite strong epidemiologic evidence linking respiratory virus infection to exacerbations of chronic obstructive pulmonary disease, many of the cellular and molecular mechanisms by which viruses cause exacerbations remain undetermined. Future research efforts to understand these mechanisms would aid the development of novel therapeutics to reduce the morbidity and mortality of this disease.
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of mortality worldwide. The Global Burden of Disease Study predicts that by 2020, COPD will have risen to be the third leading cause of mortality. The estimated annual costs of COPD are US$24 billion and 70% of these costs are related to exacerbations that require hospitalization.
Historically, bacteria have been considered the main infectious cause of COPD exacerbations. A growing body of evidence, however, implicates viral upper respiratory tract infections (URIs) as the predominant risk factor associated with exacerbations of COPD. Approximately 40-60% of all COPD exacerbations are associated with URIs. This figure may actually underestimate the true impact that viruses have on individuals with COPD. For instance, it is well recognized clinically that upper respiratory tract cold symptoms often precede COPD exacerbations by days to weeks. Therefore, clinical studies that sample for viruses during a COPD exacerbation (days to weeks after the initial onset of symptoms) may fail to detect virus despite using highly sensitive PCR technology.
In this article, we will review recent research efforts to better understand the impact of viral infections in patients with COPD. Further research to determine the cellular and molecular mechanism by which viruses cause exacerbations of COPD are needed to develop new therapeutic interventions.
Abstract and Introduction
Abstract
Purpose of Review: Chronic obstructive pulmonary disease is a major cause of morbidity and mortality worldwide. There is increasing evidence that implicates viral infections as a major risk factor for exacerbations of chronic obstructive pulmonary disease. Recent studies have attempted to better characterize the epidemiology of viral infections in chronic obstructive pulmonary disease, identify unique clinical manifestations of virusassociated exacerbations, and develop new diagnostic tools and treatments.
Recent Findings: Rhinovirus, the organism most often responsible for causing the common cold, is also the most common infectious cause of chronic obstructive pulmonary disease exacerbations. Coronavirus, influenza, respiratory syncytial virus, parainfluenza, adenovirus, and metapneumovirus are other important viral causes of chronic obstructive pulmonary disease exacerbations. These exacerbations can be severe with prolonged recovery times. Although PCR technology has dramatically increased the detection rate of viruses in patients with chronic obstructive pulmonary disease, it does not differentiate infection from colonization. The use of biomarkers represents an exciting new potential diagnostic tool that may lend new insights into the pathogenesis of viral infections in patients with chronic obstructive pulmonary disease.
Summary: Despite strong epidemiologic evidence linking respiratory virus infection to exacerbations of chronic obstructive pulmonary disease, many of the cellular and molecular mechanisms by which viruses cause exacerbations remain undetermined. Future research efforts to understand these mechanisms would aid the development of novel therapeutics to reduce the morbidity and mortality of this disease.
Introduction
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of mortality worldwide. The Global Burden of Disease Study predicts that by 2020, COPD will have risen to be the third leading cause of mortality. The estimated annual costs of COPD are US$24 billion and 70% of these costs are related to exacerbations that require hospitalization.
Historically, bacteria have been considered the main infectious cause of COPD exacerbations. A growing body of evidence, however, implicates viral upper respiratory tract infections (URIs) as the predominant risk factor associated with exacerbations of COPD. Approximately 40-60% of all COPD exacerbations are associated with URIs. This figure may actually underestimate the true impact that viruses have on individuals with COPD. For instance, it is well recognized clinically that upper respiratory tract cold symptoms often precede COPD exacerbations by days to weeks. Therefore, clinical studies that sample for viruses during a COPD exacerbation (days to weeks after the initial onset of symptoms) may fail to detect virus despite using highly sensitive PCR technology.
In this article, we will review recent research efforts to better understand the impact of viral infections in patients with COPD. Further research to determine the cellular and molecular mechanism by which viruses cause exacerbations of COPD are needed to develop new therapeutic interventions.
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