As the lungs tend to be vulnerable organs due to their exposure to harmful particles in the air, several things can cause an acute<unk>  of COPD: * Respiratory infection, being responsible for approximately half of COPD<unk> s. Approximately half of these are due to viral infections and another half appears to be caused by bacterial infections. Common bacterial pathogens of acute<unk> s 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 inhaler In one-third of all COPD<unk>  cases, the cause cannot be identified.
Acute exacerbation of chronic obstructive pulmonary disease
Acute severe asthma
Acute decompensated heart failure
Swimming-induced pulmonary edema
Occult pneumonia
Acute chest syndrome
Acute interstitial pneumonitis
Vaping-associated pulmonary injury