What is Upper Respiratory Tract Infection?
Many different types of viruses and bacteria can lead to infections in the upper respiratory tract. These infections can cause a range of illnesses, such as acute bronchitis (inflammation of the bronchial tubes), the common cold, flu, and respiratory distress syndromes (severe lung diseases). It’s often hard to clearly define these illnesses, as their symptoms and causes can overlap and are very similar.
Upper respiratory tract infections, or URIs for short, are typically characterized by short-term irritation and swelling of the upper airways, along with accompanying cough. These infections don’t show evidence of pneumonia (lung infection), don’t relate to another existing disease causing the symptoms, and don’t have a history of COPD/emphysema/chronic bronchitis (long-term lung conditions).
URIs affect various parts of our upper respiratory system including the nose, sinuses, pharynx (back of the throat), larynx (voice box), and large airways.
What Causes Upper Respiratory Tract Infection?
The common cold is quite a nuisance, causing both economic and social inconveniences. The most common virus that causes it is the rhinovirus. However, other viruses that can cause the common cold include the flu virus, adenovirus, enterovirus, and the respiratory syncytial virus. In some cases (around 15%), a sudden sore throat (pharyngitis) can be caused by bacteria—the most common one being S. pyogenes, a type of bacteria called Group A Streptococcus.
There are also certain situations or conditions that make you more likely to catch a cold or upper respiratory tract infection (URTI). For example:
- Being in close contact with kids: Daycares and schools are places where catching an URTI becomes more likely. Kids tend to spread germs more readily in these environments.
- Having certain medical conditions: People with asthma or allergies to things in the air (allergic rhinitis) are more likely to catch an URTI.
- Smoking: This habit increases your risk of getting an URTI.
- Having a weakened immune system: People with conditions such as cystic fibrosis or HIV, those who have had organ transplants, who are taking corticosteroids (which can weaken the immune system), or who have had their spleen removed are at higher risk of catching an URTI.
- Having anatomical anomalies: Facial malformations or nasal polyps can also increase the risk of catching an URTI.
Risk Factors and Frequency for Upper Respiratory Tract Infection
Upper respiratory infections (URIs) are among the top three reasons people see a doctor, costing over $22 billion each year. They result in around 10 million doctor’s appointments annually. Adults tend to get a common cold between two to three times a year, but kids can have up to eight colds a year, particularly during fall when the rhinovirus, or common cold virus, is most active.
- URIs are one of the top three reasons for outpatient doctor’s visits.
- These infections cost more than $22 billion a year.
- They result in approximately 10 million outpatient appointments annually.
- Adults get the common cold about two to three times a year.
- Kids can have up to eight colds a year, especially during the fall.
- Upper respiratory infections cause people to miss over 20 million days of school and work, contributing to significant economic loss.
The main reason adults see a doctor during the first few weeks of being ill is to get relief from symptoms. However, many of these appointments result in unnecessary antibiotic prescriptions. The economic burden generated by the missed school and work days due to URIs is substantial.
Signs and Symptoms of Upper Respiratory Tract Infection
Acute upper respiratory tract infections are health conditions that involve the inflammation of various parts of the upper respiratory system like the nose (rhinitis), throat (pharyngitis), tonsils (tonsillitis), and voice box (laryngitis). These infections often come with certain common symptoms:
- Cough
- Sore throat
- Runny nose
- Nasal congestion
- Headache
- Low-grade fever
- Pressure in the face
- Sneezing
- Feeling unwell (malaise)
- Muscle aches (myalgias)
Expect these symptoms to begin about one to three days after coming into contact with the responsible germ. Generally, they may last about a week to ten days, but could linger for up to three weeks.
Testing for Upper Respiratory Tract Infection
For a common cold, typically, classic symptoms of a virus, along with no signs of a bacterial infection or severe respiratory illness, is enough for a doctor to diagnose the condition. The diagnosis is simply based on these symptoms, hence there is usually no need for further diagnostic testing.
If your doctor wants to rule out the flu, he or she will take samples as soon after the onset of symptoms as possible. For infants and small children, the best samples can be obtained by doing a nasal swab or suctioning some fluid from the nose. For older children and adults, samples taken from the back of the nose and throat (nasopharynx) are more effective.
If your doctor needs to rule out a bacterial throat infection (pharyngitis), they can use a rapid strep test. This can help reduce the number of unneeded antibiotic prescriptions, as antibiotics don’t work against viruses.
Treatment Options for Upper Respiratory Tract Infection
The main purpose of treatment for the common cold is to help you feel better by easing symptoms like a cough, congestion, and other cold-related issues. Adult patients can use a combination of decongestant and antihistamine medications to get some relief, however, these medications aren’t recommended for children.
H1-receptor antagonists, a type of medication that blocks the action of certain chemicals in your body, might help reduce runny nose and sneezing during the first two days of a cold in adults. However, keep in mind that first-generation antihistamines can make you feel drowsy, so be careful while using them. Topical and oral nasal decongestants (like oxymetazoline and pseudoephedrine) can offer moderate relief in adults and adolescents by making it easier to breathe through the nose.
Antibiotics don’t generally help improve symptoms or shorten your cold’s duration because they’re designed to fight bacteria, not viruses which cause colds. Also, there’s no significant evidence supporting the use of dextromethorphan, a common ingredient in cough medicine, for acute (short-term) cough.
According to medical studies, taking vitamin C as a preventive measure daily could have a moderate effect on reducing the duration and severity of the common cold symptoms. However, taking high-dose vitamin C after you already have symptoms of a cold doesn’t appear to have clear benefits.
For illnesses like the flu, early antiviral treatment can help shorten how long you feel sick, reduce your time in the hospital if you need to be admitted, and lessen the risk of complications. In general, these medications should be taken within 48 hours of when your symptoms start, and treatment shouldn’t be delayed for lab test confirmations. Antiviral treatment can still provide some benefit even after 48 hours for certain high-risk groups, such as pregnant women.
The most reliable way to avoid getting the flu is to get a flu shot every year. Antiviral drugs can also help prevent the flu (they are 70% to 90% effective) and should be considered as a backup plan in certain situations or when a flu shot can’t be given. Generally, preventive antiviral medication (chemoprophylaxis) is used during flu season for high-risk individuals who cannot receive the vaccine due to certain conditions, or for whom the flu shot may not produce adequate immune response. This can also be used in cases of sudden flu outbreaks among high-risk individuals in group living situations, or for high-risk individuals who have been exposed to the flu virus.
What else can Upper Respiratory Tract Infection be?
When dealing with different types of respiratory infections, the possible conditions that professionals consider can include:
- Common Cold
- Allergic rhinitis (allergies that affect the nose)
- Sinusitis (inflammation of the sinuses)
- Tracheobronchitis (infection that affects both the windpipe (trachea) and the bronchi)
- Pneumonia (infection in one or both lungs)
- Influenza (flu)
- Atypical Pneumonia (a less severe form of pneumonia)
- Pertussis (whooping cough)
- Epiglottitis (inflammation of the tissue that covers the windpipe)
- Streptococcal Pharyngitis/Tonsillitis (strep throat/ inflammation of the tonsils caused by bacterial infection)
- Infectious Mononucleosis (a viral infection causing fever, sore throat, and swollen lymph glands)
What to expect with Upper Respiratory Tract Infection
Upper respiratory infections (URI), or simply put, common colds, are quite common during the winter season. For the most part, they’re harmless, but they can negatively affect your day-to-day life for a few weeks. Some individuals might develop more serious health conditions like pneumonia, meningitis, sepsis, and bronchitis as a result of a URI. Tragically, there are even isolated cases of deaths caused by a URI annually.
It’s also common for people to take time off from work or school when they have a URI. Sadly, patients also spend billions of dollars on remedies that don’t actually work. There is little proof that any treatment actually shortens how long a viral URI lasts. Even the vaccine, at its most effective, only works for 40-60% of individuals.
Possible Complications When Diagnosed with Upper Respiratory Tract Infection
Complications from upper respiratory tract infection don’t typically occur except in the case of the flu. It’s important to be aware that flu infections can lead to several complications. These include viral pneumonia caused directly by the flu; secondary bacterial pneumonia, which happens when bacteria infect the lungs after the flu; sinusitis, an infection of the sinuses; and otitis media, a middle ear infection. There’s also a risk of getting a co-infection with bacterial agents at the same time as the flu. Finally, people with pre-existing conditions such as asthma and chronic obstructive pulmonary disease may find their conditions worsen due to the flu. For children in particular, one of the main complications from the flu is pneumonia, a lung infection. This contributes to higher rates of illness and potential fatalities.
Complications from Flu:
- Primary influenza viral pneumonia
- Secondary bacterial pneumonia
- Sinusitis (sinus infection)
- Otitis media (middle ear infection)
- Coinfection with bacterial agents
- Worsening of pre-existing conditions such as asthma and chronic obstructive pulmonary disease
- Pneumonia in children
