What infectious respiratory conditions should I be aware of?
Author: Sharon Jang | Reviewers: Phillip Popovich , Katherine Mifflin | Published: 2 September 2020 | Updated: 10 January 2025
The heart (in the center) and lungs are complexly interconnected. The lungs help oxygenate the blood, which is pumped by the heart.7
Infectious respiratory diseases can target either the upper respiratory tract (i.e., the nose, mouth, and throat), or the lower respiratory tract (i.e., the voice box, windpipe, airways into the lungs, and the lungs). Oxygen is required for each organ to function properly. When a part of your respiratory system becomes infected, the amount of air you breathe in may be reduced. This reduces the amount of oxygen available for the body, and may quickly affect the function of the brain and other organs. Moreover, these infections can spread all over the body (sepsis). Once it spreads, it becomes more difficult to treat.
As an SCI can negatively affect respiratory and immune function, the rates of respiratory diseases, such as bacterial pneumonia and influenza, among individuals with SCI is high. In fact, respiratory diseases account for just over 80% of all deaths after SCI. In addition, respiratory conditions often present more severely in SCI. This was shown in a (weak evidence) study, where people with SCI who contracted influenza or pneumonia were 37 times more likely to die from the infection compared to an able-bodied population. Two of the most common respiratory infections in people with SCI are pneumonia and the flu. These conditions are particularly infectious, and are caught through tiny droplets of fluid in the air that may be released as a cough or a sneeze. These droplets may fall on surfaces, and can spread if someone touches the surface, then touches their mouth or eyes.
Some (weak evidence) research done to predict who is more likely to experience respiratory illness after SCI indicated that those with a complete injury and those with tetraplegia are at an increased risk of dying from a respiratory related infection. Another study found that during acute care, those with a complete injury were at a greater risk of getting pneumonia. This is related to the lack of/weakened ability to cough and clear mucus from the airways. Secondary complications that may predispose people with SCI to respiratory illnesses include: obesity, heart disease, asthma, chronic obstructive pulmonary disease (COPD), chronic coughing, chronic existence of phlegm, wheezing, and the use of pulmonary medications.
Pneumonia and SCI
Pneumonia is an infection caused by a bacteria or virus, which leads to an infection of the small air sacs in the lungs. It is one of the most common infections in acute SCI with about 30% of individuals with acute SCI experiencing pneumonia (weak evidence), dropping to about 3.5% in the chronic stages of SCI (i.e., 1-20 years post injury). Although the chance of getting pneumonia decreases after acute SCI, it is important to remember that pneumonia manifests more severely in people with SCI. That is to say, while your chances of getting pneumonia may be reduced at longer times after SCI, if you do get it, it is more severe.
Influenza and SCI
Influenza, or the flu, is a respiratory condition caused by a virus. There are multiple types and sub-types of influenza, although type A and B are the strains that most often cause the flu season. The flu virus affects the nose, throat, and sometimes the lungs, and can lead to secondary conditions such as pneumonia. Flu vaccines are recommended, especially for people with SCI as they are a vulnerable population. There is weak evidence that supports the use of flu vaccines for people with SCI, as their immune system responds similarly to the vaccine compared to able-bodied individuals. That said, those with tetraplegia may have a reduced response to the vaccine. Animal studies suggest that vaccines may be less effective with higher levels of SCI. More research is required to determine the response to influenza vaccines after SCI.
Other infectious respiratory conditions and SCI
There are many other infectious respiratory conditions that exist, such as the common cold, tuberculosis, and coronaviruses. However, little to no research has been done on the impact of these conditions in the SCI population. Although the available research is limited, it is important to note that individuals with SCI are still at an increased risk of contracting these conditions. The following section describes various respiratory infections in the able-bodied population unless otherwise noted.
Common Cold
The common cold (or simply,
the cold)
is a general term for a mild upper respiratory tract condition affecting the nose and throat. Common symptoms include stuffy nose, sneezing, sore throat, and cough. Unlike other conditions, there are multiple types of viruses that can cause a cold.
Rhinoviruses
, coronaviruses, and
influenza viruses
account for the majority of cases. The cold occurs most frequently in the fall, and decreases upon the arrival of spring. On average, a person will catch the cold once a year, but it is likely that this rate is underestimated.
Coronaviruses
A coronavirus (above), which gets its name from the spikes on the outside that resemble a crown, which is “corona” in Latin.10
Coronaviruses are responsible for many health conditions including the common cold, Middle East Respiratory Syndrome (MERS), Severe Acute Respiratory Syndrome (SARS), and novel coronavirus disease 2019 (COVID-19). These are the four strains of coronavirus now known to affect humans, and they are responsible for 10-30% of upper respiratory tract infections. Although these viruses are genetically related, they cause very different conditions. The severity of the conditions they may cause varies from mild (such as the common cold, described above), to severe (such as MERS, SARS, and COVID-19). Though MERS, SARS, and COVID-19 can all lead to pneumonia, each condition affects the body differently: MERS has a greater impact on the digestive system and kidneys, while SARS and COVID-19 most heavily impact the respiratory system, clotting function, and heart activity.
The 2019 Novel Coronavirus (COVID-19)
To date, few weak evidence studies on COVID-19 and SCI have been completed. This biggest take away is that the typical symptoms of COVID-19 as reported by the World Health Organization (i.e., cough, fever, and shortness of breath) are not necessarily applicable to people with spinal cord injuries. As coughing is often impaired with SCI, it can be absent in reported cases of COVID-19 in people with SCI. Instead, common symptoms of COVID-19 in people with SCI include a fever and feeling weaker than normal. Other symptoms that have been reported include shortness of breath, body aches/worsening pain, sweating, chest pain, and increased spasticity, a worsened ability to clear secretions, and abnormally fast breathing. Although people with SCI may have fewer of the typical COVID-19 symptoms, one study has found that they are more likely to experience COVID-19 more severely compared to able-bodied individuals. |
Tuberculosis
Tuberculosis is an infection of the lungs that can be caused by
Mycobacterium tuberculosis
bacteria. The presence of tuberculosis is higher in developing countries in comparison to developed countries. This is related to factors such as lower rates of vaccination and higher rates of HIV (an immune compromising condition) in developing countries. Treating tuberculosis is particularly difficult, as many strains of the virus/bacteria are resistant to drugs.
Upper respiratory tract infections
Upper respiratory tract infections are a group of conditions that affect the nose and throat. Some conditions include pharyngitis (sore throat) and laryngitis (inflammation of the voice box; when you lose your voice). These infections are of particular note to those using ventilators, as over 90% of pneumonia and hospitalizations start with an upper respiratory tract infection.