Although the terms "sputum" and "mucus" are often used interchangeably, they are in fact distinct substances. A variety of mechanisms leads to hyperproduction of mucus in COPD. "Sputum" describes the expectorated secretions.
Patients with COPD normally produce sputum that is clear.
The hyperproduction of mucus is compounded by difficulty in clearing secretions owing to several factors, including an ineffective cough secondary to reduced peak expiratory flow and respiratory muscle weakness. Poor ciliary function and distal airway occlusion also can hamper the ability to clear secretions.
Bacterial infection can lead to mucus hypersecretion in COPD. Other triggers include exposure to cigarette smoke, acute and chronic viral infection, and inflammatory cell activation of mucin gene transcription.
Learn more details about the presentation of COPD.
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Cite this: Zab Mosenifar. Fast Five Quiz: COPD Presentation and Diagnosis - Medscape - Apr 27, 2021.