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The upper part of the respiratory system includes the ears, nose, sinuses, mouth, and throat. It also includes the main bronchi or windpipes, which are the air-carrying tubes in the chest. The upper respiratory system is the most commonly infected area in the body.
What is going on in the body?
The term upper respiratory infection (URI) includes the common cold, sore throats, and flu. URIs are usually caused by a virus but may also be due to bacteria or other organisms. An upper respiratory infection is rarely serious but often causes bothersome symptoms.
What are the signs and symptoms of the infection?
Many of the signs and symptoms depend on the type of upper respiratory infection. Common symptoms of URIs include: What are the causes and risks of the infection?
There are many different types of upper respiratory infections, including:
Other types of URI may also occur, but they are less common.
- the common cold, usually due to a virus
- the flu, or influenza virus infection, which causes more severe symptoms than a cold
- acute sinusitis or chronic sinusitis, which involve the nasal sinuses
- otitis externa, or infection of the outer ear
- acute otitis media, or infection of the middle ear behind the eardrum
- pharyngitis, or sore throat
- acute bronchitis, an infection in the lower windpipes
- croup, which is a viral infection of the main windpipe that is usually only seen in children
- epiglottitis, a bacterial infection of the main windpipe that is more commonly seen in children
What can be done to prevent the infection?
Many cases of upper respiratory infection cannot be prevented. Almost all URIs are contagious, so avoiding sick people can help prevent some cases. Frequent hand washing can also help reduce the spread of many URIs. Vaccines are used to help prevent some cases. For example, the flu Injection can be given to high-risk individuals every autumn to help prevent the flu.
How is the infection diagnosed?
The doctor diagnoses most URIs after a history and physical examination.
In some cases, further tests may be ordered. For example, the back of the throat may be swabbed if strep throat is suspected. This swab test, called a throat culture, can check for the bacteria that cause this infection. A blood test called an antibody titre may be done if certain infections are suspected. A chest X-ray may be ordered to make sure pneumonia, a more serious infection deep in the lungs, is not present. Other tests may be ordered in certain cases.
What are the long-term effects of the infection?
Most URIs are mild and go away with or without treatment. However, some URIs can be more serious and may have long-term effects. For example, untreated strep throat can lead to kidney damage or rheumatic fever, which can damage the heart. Acute otitis media can result in hearing loss. Severe croup and epiglottitis may be life-threatening. URIs can also put people at risk of getting pneumonia, which may be life-threatening, especially in the elderly and very young.
What are the risks to others?
Most upper respiratory infections are highly contagious. They are transmitted through respiratory secretions. Sneezing and coughing can spread these droplets. The germ can also be passed on when an individual with an upper respiratory infection touches his or her nose and then handles an object that another person later touches. The second person can then pick up the germ from the object and transfer it into his or her own respiratory tract by touching the face.
What are the treatments for the infection?
For URIs caused by a virus, antibiotics are not helpful. Someone with a cold should remember that antibiotics can cause more harm than good in these cases. In severe cases of the flu, antiviral medications such as rimantadine or oseltamivir may be given. For bacterial infections such as bacterial pneumonia, antibiotics are given.
Other treatments may help relieve symptoms. Other over-the-counter and prescription medications can be used for symptoms such as cough, fever, muscle aches, runny nose, or stuffy nose.
What are the side effects of the treatments?
All medications have possible side effects. Common antibiotics can cause allergic reactions, stomach upset, and other effects.
What happens after treatment for the infection?
Most people recover completely within a few days. Having a URI usually doesn't prevent a person from catching another URI in the future. If long-term effects such as kidney damage occur from the URI, a person may need further treatment.
How is the infection monitored?
If symptoms continue to get worse or fail to improve after several days, the doctor should be told. In severe cases, a person may need to be watched in the hospital for a few days.
Author: Adam Brochert, MD
Reviewer: eknowhow Medical Review Panel
Editor: Dr John Hearne
Last Updated: 16/1/2005
Potential conflict of interest information for reviewers available on request