Exacerbations of COPD
People with COPD often experience exacerbations. The term "exacerbation" refers to the aggravation of the symptoms or an increase in the severity of the disease. The duration of an exacerbation can vary greatly—from hours to several days. Exacerbations often require a call or visit to the clinician, an emergency room visit, and a possible change in medication. An exacerbation is defined as a complex of respiratory events reported as adverse events, with a duration of 3 or more days.
Exacerbations may cause symptoms specific to the respiratory process to increase. The patient may experience increased dyspnea, a productive cough with an altered sputum, and fever. While a patient’s dyspnea may vary day to day when the COPD is stable, the dyspnea present in an exacerbation exceeds the worst of those variations. The sputum may increase or be more purulent and change color. The patient may also experience nonspecific symptoms such as malaise, fatigue, insomnia, sleepiness, or depression.
Each COPD patient is likely to experience 1 to 4 exacerbations a year, or a total of 15 to 16 million episodes in the US alone. While many patients experience these exacerbations, it is estimated that they only report about 50% of all episodes to physicians. Frequent exacerbations have been associated with a poor quality of life and a high economic burden.
Exacerbations of COPD are usually caused by an infection of the lower respiratory tract. The most common causes of infection are:
- aerobic Gram-positive and Gram-negative bacteria
- respiratory virus
- atypical bacteria
- These pathogens may be present alone or in combination during an exacerbation.
In summary;
- exacerbations are referred to as an aggravation of symptoms or increase in the severity of the disease
- generally have a duration of 3 or more days
- most frequently caused by an infection in the lower tract:
- aerobic Gram-positive and Gram-negative bacteria
- respiratory virus
- atypical bacteria
- onset early in life
Gram-Positive / Gram-Negative BacteriaControversy over the role of bacteria in exacerbations of COPD has been present for several decades. In the 1950s and 1960s, British researchers suggested that exacerbations of COPD were caused by bacterial infection and mucus hypersecretion. |
Respiratory VirusStudies have indicated that approximately one-third of all episodes of COPD exacerbations are associated with viral infection. Lab tests show that the viral infection present during an exacerbation is significantly greater than during a stable period of COPD. |
Atypical BacteriaAtypical bacteria (primarily Chlamydia and Mycoplasma) have been implicated in less than 10% of COPD exacerbations, although 1 study conducted in Turkey found that it was the sole causal agent in 16% of exacerbations and 1 of several causal agents in 6% of cases. |
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