Upper Respiratory Infection
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 causes and risks of the infection?
There are many different types of upper respiratory infections, including:
the common cold, usually due to a virus
influenza virus infection (flu), 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
Other types of URI may also occur, but they are less common.
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 viruses and bacteria.
Vaccines are used to help prevent some types of URI. For example, influenza vaccine is available each fall for anyone, and is especially recommended for the elderly and others at high risk of complications from flu.
How is the infection diagnosed?
Most cases of the common cold do not come to the attention of a healthcare professional. If a person has symptoms and signs suggestive of influenza, the professional may not perform tests to confirm the diagnosis, because the treatment is limited to relief of symptoms.
In some instances, a specimen for viral isolation may be taken to help public health officials determine which strains of flu are circulating in the community. This information helps to guide vaccine recommendations.
In other cases, different types of 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 titer 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.
Long Term Effects
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 dangerous 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, spread by sneezing and coughing. The viruses and bacteria 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 become infected by touching his or her face with contaminated hands.
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 (i.e., Flumadine), amantadine (i.e., Symmetrel), zanamivir (i.e., Relenza) or oseltamivir (i.e., Tamiflu) may be given.
For bacterial infections such as bacterial pneumonia, antibiotics are given. Other treatments may help relieve symptoms. A number of over-the-counter or prescription medications can be used for symptoms such as cough, fever, muscle aches, runny nose, or stuffy nose.
A decongestant called phenylpropanolamine (PPA), found in many over-the-counter cold remedies, has recently been linked to strokes in young women. The Food and Drug Administration (FDA) has requested that manufacturers stop producing medications containing PPA. In view of the FDA's public health advisory, anyone who has products at home containing phenylpropanolamine should discard them.
The Natural Medicines Comprehensive Database has evaluated the scientific studies looking at herbs, vitamins and supplements used in the treatment of the common cold. The NMCD concludes that the following are "possibly effective" in the treatment, but not prevention, of the common cold:
The NMCD concludes that there is "insufficient evidence" to use any of the following in the treatment of the common cold:
A number of natural medications (herbs, vitamins or supplements) have been studied in the treatment of influenza. The Natural Medicines Comprehensive Database rates elderberry and N-Acetyl Cysteine as "possibly effective" while concluding that zinc and zinc lozenges are "possibly ineffective." They've determined that there is "insufficient evidence" at the present time for andrographis, echinacea, Panax ginseng and Oscillococcinum for treating a URI from the influenza virus.
What are the side effects of the treatments?
Most medications have possible side effects. 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. Because such a large number of different viruses cause URI, having one generally does not 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 healthcare professional should be told. In severe cases, a person may need to be watched in the hospital for a few days.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.
Rudolph's Fundamentals of Pediatrics, 1998, Rudolph et al.