Cough cough cough cough. Color of sputum may be associated with new bacterial colonization: 18% of clear phlegm grew bacteria, compared to 59% of green sputum and 46% of yellow sputua (PubMed), although treating based on color change does not get a patient better faster. Sputum is green due to myeloperoxidase in WBC.
There is a curious association between vitamin D deficiency and developing a URI. And with tuberculosis as well. Not a big deal if you live in Florida, but it is if you live in Finland (PubMed) or, perhaps, Oregon.
Acute is mostly viral Adenovirus, Coronavirus, Coxsackievirus A21, Human metapneumovirus, Parainfluenza virus, Respiratory syncytial virus, Rhinovirus.Mycoplasma pneumoniae, B. pertussis or C. pneumoniae strain TWAR are the bacteria occasionally involved.
The color of the sputum does not help in determining whether or not antibiotics are needed (PubMed). I, however, am more likely to gag if it is green.
Acute bronchitis: most cases do not require antibiotics, as if that is going to stop anyone from giving inappropriate antibiotics. If there is a concern for Mycoplasma pneumoniae, B. pertussis or C. pneumoniae treat accordingly.
Chronic bronchitis: aka COPD.Patients get exacerbations with they acquire a NEW strain of Haemophilus influenzae OR Moraxella catarrhalis OR Streptococcus pneumoniae. Usually treat acute exacerbations with any of a variety of po medications: amoxicillin OR TMP/Sulfa OR quinolone OR doxycycline OR macrolides OR one of the innumerable and interchangeable po cephalosporins for 7 or 10 days. Does it do anything? Perhaps possible maybe (PubMed).
Do antibiotics do much for acute respiratory infections? Not really, although in large populations there is a decrease pneumonia hospitalizations. The number needed to treat to prevent 1 hospitalization for pneumonia is 12,255; hardly worth it (PubMed).
NSAIDS during an acute respiratory infections increase MI risk 3.4x (PubMed).
We do what we do because we do. Skooby Dooby Do.
Gargling three times a day decreases the risk of Japanese URI (PubMed). But yodeling does nothing.
See pearls above.