Respiratory tract infections are a common cause of illness. The most widespread respiratory tract infection is the common cold.
The respiratory tract
The respiratory tract is a general term that is used to describe all the parts of the body that are involved in helping a person to breathe. Health professionals generally make a distinction between:
- the upper respiratory tract, and
- the lower respiratory tract.
Upper respiratory tract
The upper respiratory tract consists of:
- the nose,
- the sinuses - air-filled cavities that are found inside the cheekbones and forehead,
- the mouth (including the tonsils),
- the throat,
- the pharynx - which is at the back of the throat and prevents foreign objects, such as food, falling down into the lungs, and
- the larynx or ‘voice box’ - which is the part of the throat that contains the vocal cords.
Common upper respiratory tract infections include:
- the common cold,
- sore throat - usually due to an infection of the pharynx (pharyngitis),
- tonsillitis - infection of the tonsils,
- sinusitis - infection of the sinuses, and
- laryngitis - infection of the larynx.
Lower respiratory tract
The lower respiratory tract consists of:
- the trachea (windpipe) - the tube that connects the throat to the lungs,
- the bronchi - the two branches that the trachea divides into as it enters the lungs,
- bronchioles - the tiny airways that are found throughout the lungs, and
- the alveoli - tiny air sacs at the end of the bronchioles.
Common lower respiratory tract infections (LTRIs) include:
- bronchitis - infection of the bronchi, and
- pneumonia - infection of the bronchioles and alveoli.
There are also certain types of infection, such as the flu (influenza) that can affect both the upper and lower respiratory tract.
How common are respiratory tract infections?
Respiratory tract infections are very common. They are believed to be one of the leading reasons why people visit their GP or pharmacist.
The respiratory tract is much more vulnerable to infection than other parts of the body. This is because it is easy for bacteria, or viruses, to enter the tract when someone breathes in.
Respiratory tract infections are more common during the winter. This is possibly due to the fact that during the winter months people are more likely to stay inside in close contact with each other.
Children tend to get more upper respiratory tract infections, such as colds, than adults. This is because they have not yet built up immunity to the many viruses that can cause colds.
Outlook
The outlook for respiratory tract infections is generally good. Most infections are self-limiting, which means that they will pass without the need for treatment.
However, extra care and additional treatment may be required for people who are more vulnerable to the effects of infection. Those who may require this include:
- the very young,
- the elderly,
- people with a pre-existing lung condition, and
- people with a weakened immune system.
A number of vaccines are available for some of the viruses and bacteria that cause infection, such as the flu vaccine and the pneumococcal vaccine (pneumococcal bacteria is a family of bacteria that can cause pneumonia). See the ‘prevention’ section for more information.