Final answer:
Purulent foul-smelling sputum is often an indication of pneumonia. Pneumonia is a common inflammatory disease of the respiratory tract in which the alveoli become filled with fluid that inhibits gas exchange.
Step-by-step explanation:
Purulent foul-smelling sputum is often an indication of pneumonia. Pneumonia is a common inflammatory disease of the respiratory tract in which the alveoli become filled with fluid that inhibits gas exchange. Bacterial pneumonia, caused by pathogens such as Streptococcus pneumoniae, is one of the most common causes of pneumonia.