What kind of sputum is typically associated with lung infections?

Purulent sputum is typically associated with lung infections, as it signifies the presence of pus due to infection. This type of sputum often appears thick and can be yellow or green in color, which indicates the body’s immune response to bacterial infection or inflammation in the lungs. The presence of white blood cells, dead bacteria, and cellular debris contributes to its purulent characteristics.

In contrast, clear sputum is often linked to non-infectious conditions or can be seen in early stages of certain infections, while frothy sputum is commonly associated with conditions such as pulmonary edema rather than straightforward infections. Thick and white sputum may occur in conditions like asthma or chronic bronchitis rather than being specifically indicative of an active lung infection. Thus, purulent sputum serves as a clear marker for infection, making it the correct choice in this context.