Causes
As the lungs tend to be vulnerable organs due to their exposure to harmful particles in the air, several things can cause an acute exacerbation of COPD:

Respiratory infection, being responsible for approximately half of COPD exacerbations. Approximately half of these are due to viral infections and another half appears to be caused by bacterial infections. Common bacterial pathogens of acute exacerbations include Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis. Less common bacterial pathogens include Chlamydia pneumoniae and MRSA. Pathogens seen more frequently in patients with impaired lung function (FEV<35% of predicted) include Haemophilus parainfluenzae (after repeated use of antibiotics), Mycoplasma pneumoniae and gram-negative,  opportunistic pathogens like Pseudomonas aeruginosa and Klebsiella pneumoniae. Allergens, e.g., pollens, wood or cigarette smoke, pollution
Toxins, including a variety of different chemicals
Air pollution
Failing to follow a drug therapy program, e.g. improper use of an inhalerIn one-third of all COPD exacerbation cases, the cause cannot be identified. Diagnosis
The diagnostic criteria for acute exacerbation of COPD generally include a production of sputum that is purulent and may be thicker than usual, but without evidence of pneumonia (which involves mainly the alveoli rather than the bronchi). Also, diagnostic criteria may include an increase in frequency and severity of coughing, as well as increased shortness of breath.A chest X-ray is usually performed on people with fever and, especially, hemoptysis (blood in the sputum), to rule out pneumonia and get information on the severity of the exacerbation.
Hydrometra is a genus of water measurers in the family Hydrometridae. There are more than 120 described species in Hydrometra. See also
List of Hydrometra species

References
Further reading


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