An<unk>  or acute<unk> s of<unk>  bronchitis (AECB), is a sudden worsening of<unk><unk>  pulmonary<unk>  (COPD) symptoms including shortness of breath, quantity and color of phlegm that typically lasts for several days. It may be triggered by an infection with bacteria or viruses or by environmental pollutants. Typically, infections cause 75% or more of the<unk> s; bacteria can roughly be found in 25% of cases, viruses in another 25%, and both viruses and bacteria in another 25%. Airway inflammation is increased during the<unk>  resulting in increased hyperinflation, reduced expiratory air flow and decreased gas exchange.<unk> s can be classified as mild, moderate, and severe. As COPD progresses,<unk> s tend to become more frequent, the average being about three episodes per year.
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