Infectious Diseases A–Z: What you need to know about pneumonia Pneumonia is an infection that inflames the air sacs in one or both lungs, and can range in seriousness from mild to life-threatening Pneumonia can affect anyone, but the age groups at highest risk are children younger than age 2 and people older than age 65
Consumer Health: Recognizing the signs of pneumonia Pneumonia is an infection that inflames the air sacs in one or both lungs The air sacs may fill with fluid or pus, causing cough with phlegm or pus, fever, chills, and difficulty breathing Pneumonia can range in seriousness from mild to life-threatening
Pneumonitis - Symptoms and causes - Mayo Clinic Lung infections such as pneumonia also can cause lung tissue to become inflamed But pneumonitis generally refers to inflamed lung tissue not caused by an infection Pneumonitis is a result of an extra strong defense response by the body's immune system to an irritating substance