A lower respiratory tract infection (LRTI) is an infection affecting structures of the lower respiratory tract, such as the bronchi, bronchioles, or lungs.
Lower respiratory tract infections can be caused by viruses, bacteria, fungi, and other infectious agents. Bronchitis and pneumonia are important examples, although not every case of bronchitis is infectious.
Symptoms may include cough, fever, difficulty breathing, chest discomfort, and increased mucus production. Severity ranges from relatively mild illness to life-threatening disease.
QUICK FACT
Pneumonia is a lower respiratory tract infection, but not every lower respiratory tract infection is pneumonia.
COMMONLY CONFUSED WITH
Upper respiratory tract infection: Upper respiratory infections primarily affect structures such as the nose, sinuses, and throat, while lower respiratory infections affect the lower airways and lungs.
SEE ALSO