Breathing stops.
Moderate to severe difficulty breathing occurs. This means a person may have trouble talking in full sentences or breathing during activity.
Severe chest pain occurs, or chest pain is quickly getting worse.
You cough up large amounts of bright red blood.
Cough up a couple of tablespoons of blood.
Have shortness of breath or wheezing that is quickly getting worse.
Start having new chest pain.
Are coughing more deeply or more often, especially if you notice an increase in mucus (sputum) or a change in the color of the mucus you cough up.
Have increased swelling in your legs or belly.
Have a high fever [over 101°F (38.3°C)].
Develop flu-like symptoms.