Topic Overview
Most adults and older children
have several respiratory infections each year. Respiratory problems can be as
minor as the common cold or as serious as
pneumonia. They may affect the upper respiratory
system (nose, ears, sinuses, and throat) or the lower bronchial tubes and
lungs. See a picture of the
respiratory system
.
Upper respiratory system
The upper respiratory
system includes the nose, ears, sinuses, and throat. When you have an upper
respiratory infection, you may feel uncomfortable, have a stuffy nose, and
sound very congested. Other symptoms of an upper respiratory infection
include:
- Facial pain or pressure.
- A runny
or stuffy nose, which may lead to blockage of the nasal passages and cause you
to breathe through your mouth.
- A sore
throat.
- Irritability, restlessness, poor appetite, and decreased
activity level.
- Coughing, especially when lying
down.
- Fever that occurs suddenly and may reach
39°C (103°F) or higher.
Lower respiratory system
The lower respiratory
system includes the bronchial tubes and lungs. Respiratory problems are less
common in the lower respiratory system than upper respiratory system.
The symptoms of a lower respiratory (bronchial tubes and lungs) problem
usually are more severe than symptoms of an upper respiratory (ears, nose,
sinuses, and throat) problem.
Symptoms of lower respiratory system
infections include:
- Cough, which continues throughout the day and
night, often producing green, yellow, brown, or grey mucus (sputum) from the
lungs.
- Fever, which may be high with some lower respiratory system
infections, such as pneumonia.
- Difficulty
breathing. You may notice:
- Shortness of
breath.
- Grunting, which is heard during the breathing out
(exhaling) phase of breathing.
- Wheezing.
- Flaring the nostrils and using
the neck, chest, and abdominal muscles to breathe, causing a "sucking in"
between or under the ribs (retractions).
- Chest pain with exertion or when you take a
deep breath.
Respiratory problems may have many causes.
Viral infections
Viral infections are the most
common cause of upper respiratory symptoms. Symptoms of a viral illness often
come on quickly (over hours to a day or two) without prior illness. Common
viral illnesses include colds and influenza (flu).
- Colds are minor upper respiratory illnesses
that usually go away without treatment. Symptoms may include cough, mild sore
throat, nasal congestion, runny nose or sneezing, and occasionally a fever of
38°C (101°F) or lower.
- Influenza (flu) symptoms are usually more severe than
a cold. The key symptoms in adults are fever, often
40°C (104°F) or higher, and
body aches. Headache, eye pain, muscle aches, and cough are also common. For
more information, see the topic
Influenza.
Antibiotics are not used to treat viral illnesses and do
not alter the course of viral infections. Unnecessary use of an antibiotic
exposes you to the risks of an
allergic reaction and antibiotic side effects, such as
nausea, vomiting, diarrhea, rashes, and yeast infections. Antibiotics also may
kill beneficial bacteria and encourage the development of dangerous
antibiotic-resistant bacteria.
Severe
acute respiratory syndrome (SARS) is caused by a type of
coronavirus, a family of viruses that often cause mild to moderate upper
respiratory
illness, such as the common cold. For more
information, see the topic
Severe Acute Respiratory Syndrome (SARS).
Bacterial infections
Bacterial infections may
develop after a viral illness, such as a cold or influenza, and are less common
than viral illnesses. Bacterial infections may affect the upper or lower
respiratory system. Symptoms tend to localize to one area. In the upper
respiratory system, the most common sites of bacterial infections are the ears,
sinuses, and throat. In the lower respiratory system, the most common sites are
the bronchial tubes (bronchitis) and
the lungs (pneumonia).
Bacterial infections are more
common in smokers, people exposed to second-hand smoke, and people with chronic
lung disease (such as
asthma or chronic obstructive pulmonary disease [COPD]) and other chronic medical problems. Antibiotics
can effectively treat most bacterial infections.
Allergies
Allergies, especially
hay
fever, are another common respiratory problem. Symptoms include
sneezing, clear runny drainage from the nose and eyes, itchy eyes or nose, and
stuffy, congested ears and sinuses. The symptoms of allergies often last longer
than a typical viral respiratory infection. For more information, see the topic
Allergic Rhinitis.
Asthma
Asthma is a
chronic disease of the respiratory system. It causes inflammation and narrowing
in the tubes that carry air to the lungs (bronchial tubes). The inflammation
leads to difficulty breathing,
wheezing, tightness in the chest, and cough.
Asthma often begins during childhood and may last throughout a person's
life. The cause of asthma is not clearly known. It is more common in people who
also have allergies. For more information, see the topic the topic
Asthma in Children or
Asthma in Teens and Adults.
Review the Emergencies and Check Your Symptoms sections
to determine if and when you need to see a doctor.