Viral respiratory infections ‘a common cause of COPD exacerbations’
MedWire News: Viral infections of the upper respiratory tract are a significant cause of acute exacerbations of chronic obstructive pulmonary disease (AECOPD), results from a Swiss study suggest.
"Respiratory viruses are frequently recovered in the upper respiratory tract during AECOPD, but their role as contributing pathogens remains unclear," explain Omar Kherad (University of Geneva) and team.
To investigate further, and to assess whether procalcitonin and C-reactive protein levels indicate the presence of viral infections among such patients, the researchers studied 86 patients (64% men), aged an average of 72 years, who were admitted to the emergency department suffering from an AECOPD between 2007 and 2008.
Nasopharyngeal swabs were collected from the patients at admission and after recovery (4 months after the index AECOPD) and examined for the presence of 14 respiratory viruses using reverse transcriptase-polymerase chain reaction (RT-PCR).
At admission, 44 (51%) patients tested positive for upper-respiratory viral infections. Specifically, picornavirus was detected in 22 patients, metapneumovirus in seven, coronavirus in eight, influenza A/B in two, parainfluenza in two, and respiratory syncytial virus in three patients, with three patients showing evidence of dual infection.
After recovery, just eight (11%) of 71 patients showed evidence of upper-respiratory viral infections. Of these eight patients, five had no evidence of infection during the index AECOPD, suggesting a new viral infection acquired during the follow-up period. Fifteen patients were lost to follow up.
There were no significant differences in procalcitonin and C-reactive protein levels between patients with and without evidence of a viral infection during the index AECOPD, the researchers note.
Kherad and colleagues conclude in the journal Chest: "Prevalence of viruses, as detected from nasopharyngeal swabs by RT-PCR, is high in AECOPD and low after clinical recovery, suggesting that AECOPD are frequently triggered by viral infections initiated in the upper respiratory tract.
"In this study, current biologic markers such as C-reactive protein and procalcitonin could not discriminate between viral and nonviral AECOPD."
They add: "Rapid virological diagnostic procedures, therefore, are highly needed to accurately confirm a viral etiology in the presence of a COPD exacerbation and subsequently to apply appropriate treatment strategies."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Mark Cowen