**2. Etiology of exacerbations**

Tracheobronchial infections (40-50% bacterial, 30-40% viral, 5-10% atypical bacteria) are involved in 50-70% of COPD exacerbations. Another factor is air pollution that is thought to be involved in 10% of exacerbations. In about 30%, the etiologic factor cannot be identified(Sapey Stockley 2006). Other medical problems, such as congestive heart failure, nonpulmonary infections, pulmonary embolism, and pneumothorax, can also lead to a COPD exacerbation.

*Infections:* 

Bacterial: (Streptococcus pneumonia, Haemophilus influenza, Moraxella catarrhalis, Chlamydia pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus)

Viral: (Rhinovirus, influenza, adenovirus, parainfluenza, coronavirus, respiratory cincitial virus)

*Environmental factors:* 

Indoor and outdoor air pollution

Management of Acute Exacerbations 293

Another classification approach is suggested by Anthonisen and colleagues (Anthonisen et al. 1987). According to this approach, severe exacerbations requiring antibiotheraphy are characterized by the presence of increase in all of the 3 criteria: dyspnea, sputum production and sputum purulence. Moderate exacerbations show only the 2 of these criteria, while in mild exacerbations, only one of these criteria is present with a recent history of upper airway infection or fever or symptoms like wheezing, cough, tachypnea

Diagnostic evaluation of a suspected COPD exacerbation varies whether the patient will be treated in the hospital or at home. Routine sputum culture evaluation is not recommended for mild exacerbations. In case of a severe exacerbation, oxygen saturation must be measured by a pulse oxymeter. Patients who are referred to a hospital must be evaluated by advanced diagnostic tests such as arterial blood gas analysis, chest x-ray, sputum gram staining and cultures, electrocardiography and blood drug levels if possible

**Diagnostic procedures Mild Moderate Severe** 

Oxygen saturation Yes Yes Yes

Arterial blood gas analysis No Yes Yes

Chest X-ray No Yes Yes

Blood tests \* No Yes Yes

Sputum gram staining and cultures No Yes Yes

ECG No Yes Yes

BNP † No No Yes

Cardiac enzyme measurement ‡ No No Yes

About 50% of COPD exacerbations are not reported to physicians(Seemungal et al. 2000). This suggests that half of the exacerbations are mild and do not require hospitalization.

1. Onset of new physical signs such as cyanosis, peripheral edema, detoriation in the

2. Having severe or very severe COPD and being under long term oxygen therapy at

†: One third of dyspnea in chronic lung disease may be attributable to congestive heart failure. ‡: Cardiac ischemia (myocardial infarction is underdiagnosed in patients with COPD). Table 2. Diagnostic evaluation of patients with suspected COPD exacerbation

Indications for hospitalization of a patient with COPD exacerbation are as follows:

\*: blood cell count, serum electrolytes, urea, creatinine, liver function tests.

\*\*: theophylline, warfarin, carbamazepine, digoxin

neurological status, arrhythmias etc.

home.

Serum drug concentrations\*\* If possible If possible If possible

and tachycardia.

(Table 2).

Patients who are known to have COPD are defined as an exacerbation when they are admitted to the emergency departments with increased dyspnea during fall and winter. The main issue is the underestimation of non-infectious causes such as pulmonary embolism, pleural effusion, pneumothorax, thoracic traumas, inappropriate use of sedatives, narcotics and beta blockers, arrhythmias, cardiac failure or problems in the use of long term oxygen therapy. Therefore, in a COPD patient with increased dyspnea, first the diagnosis of exacerbation should be established correctly and then the etiology should be identified as infectious or non-infectious.

Potentially pathogen bacteria are identified in 30% of sputum cultures in mild exacerbations, while this rate can be up to 70% in severe exacerbations in patients who need ventilatory support (Sapey Stockley 2006; Siddiqi Sethi 2008).
