I would like to start with defining pneumonia. Pneumonia is a lung infection with a number of different potential causes. It can be caused by a virus, bacteria, or less commonly, a fungal agent. The symptoms include cough, increased sputum production, fever, difficulty breathing, chest pain, and sometimes altered levels of consciousness in the more severe pneumonias.
What is actually happening in the lungs is that the alveolar spaces are becoming inflamed, and eventually, fluid-filled. Thinking back to anatomy and physiology for a moment, you will recall that the bronchi divide into bronchioles and the endpoint following the bronchioles are the alveolar sacs. It is those sacs, or spaces, that become inflamed in pneumonia; pneumonia is an infection of the alveolar spaces. The epithelium starts to thicken, surfactant production is reduced, respiratory rate increases because air exchange is not happening as efficiently, and the infectious material then starts to accumulate not just in the alveolar spaces, but eventually in the air spaces at large. If the pneumonia is progressing and not being treated or not responding to treatment, that infiltrate grows and the surface area for gas exchange begins to diminish. Then, respiration becomes more difficult.
It is not the easiest diagnosis to make. Physicians generally make a diagnosis of pneumonia based on a review of the history, the clinical signs and symptoms that I mentioned, and a chest x-ray. But this is far from a perfect science.
Chest X-Ray (CXR) Terminology
As SLPs, when we read the chest x-ray reports it is sometimes difficult to tell exactly what is going on. It is sometimes difficult to understand the terminology that the radiologists use, so I thought it might be helpful to discuss some of the terminology used when reviewing a chest x-ray. If you see the terms density, opacity, consolidation or infiltrate, essentially the radiologist is indicating that he or she is seeing some filling of the air spaces. It could be fluid, it could be bacteria, it could be white blood cells. We cannot tell that from a chest x-ray, but these terms are telling us that something is in the air spaces. Any of these terms, in fact, may be associated with a pneumonia.
You might see the term atelectasis. This term is referring to alveolar collapse, and so there is a subsequent loss of lung volume. This, too, is frequently associated with pneumonia.
The term edema suggests that there is fluid. You can see obvious fluid in the alveolar spaces or in the interstitial spaces. Effusion means there is fluid in the pleural cavity. Edema and effusion are typically not associated with pneumonia. These are more likely to be associated with congestive heart failure or other lung disorders.
Once the diagnosis of the pneumonia has been made, the physician generally treats it with antibiotics. They try to prescribe antibiotics based on the cause of the pneumonia, or what they believe to be the cause of pneumonia, which is not always clear. I will talk about that later in the course. Some patients might require oxygen because there can be a significant loss of air space in the lungs. Breathing can be very difficult for patients with pneumonias at times. There may be respiratory therapy treatments, and there may be fluid administered as well.
Pneumonia Cost - Dollars
There is a huge cost to pneumonias, not just in financial terms. Data around healthcare costs can be very difficult to get. It takes a long time to compile, particularly if you are trying to look at Medicare costs and data. Two studies, frm 2012 and 2015, may seem a bit older but they are in fact fairly current since it takes several years for insurance companies and healthcare systems to compile data and make it available for analysis.
Having said that, what is the data telling us? The 2012 study (Parks Thomas et al.) suggests that the Medicare cost for patients with pneumonia - the calculated cost during the pneumonia episode and for a year after - was almost $16,000 higher than costs for taking care of age-matched peers who did not have pneumonia. This results in an additional $87 billion or more to Medicare annually for the management of pneumonia. This is Medicare data, so these are people who are 65 or older.
There is also some data that came from a Veteran's Health Administration (VA) study (McLaughlin et al., 2015). They found that the annual dollar amount they were spending was about $750 million to treat vets with pneumonia, and most of that was spent on patients who were over 65 years of age. So we know that the elderly patients are certainly higher risk. They have more severe pneumonias that keep them in the hospital longer.
There is also some data that came from commercial insurance (Sato et al, 2013). The mean cost for an outpatient episode is $2,212. The mean cost for an inpatient episode is $27,661 but some payers reported episodes as high as $51,219. They were looking at adult patients who were older than 50 years old, in other words not a pediatric population. The cost for managing patients with pneumonia is certainly higher on the inpatient side than the outpatient side. That is no surprise, but there is a lot of variability too. Overall, I think we can conclude that treating pneumonia and taking care of people with pneumonia costs a lot of money.
Pneumonia Cost - Mortality
There is also a cost in terms of mortality. People die from pneumonia. It is a serious infection, particularly for elderly patients and patients who are compromised to begin with. Here is some Medicare data. The 30-day mortality rate associated with a pneumonia diagnosis is 6.2% for community-acquired pneumonia (CAP) and over 13% for hospital-acquired pneumonia. (I will spend a little time teasing out the differences between pneumonia types shortly.) Yu and colleagues in 2012 found a 30-day mortality rate of 8.5% for inpatients and 3.8% for outpatients. There is also some data from the Veteran's Health Administration showing a very high mortality rate of 36%; but this study was limited to patients who were not only over 65 years of age, but also at higher risk due to multiple health problems.
It is clear that pneumonia is a serious problem, but it is important to remember that not all pneumonias are aspiration pneumonias and pneumonia is not the only potential consequence of aspiration. Those of us who work in healthcare sometimes carry the burden of these folks with pneumonias. We first have to determine if the patient's pneumonia was in fact caused by aspiration because there are a number of things that that can cause pneumonia. We also have to broaden our scope to think about some of the other consequences of aspiration. In other words, just because a person doesn’t have pneumonia doesn’t mean that there aren’t consequences to the aspiration.
Types of Pneumonia
Let's discuss some of the different types of pneumonias. This is a little muddy, truth be told. There is not agreement in the medical community amongst physicians or in the literature around how to use terms like community-acquired, healthcare-acquired, or nosocomial aspiration pneumonia, but I will do my best to divide these pneumonias into categories and talk about how this terminology might be used by different folks.
Community-acquired pneumonia. The term community-acquired pneumonia is generally used in reference to a viral pneumonia. These are generally pneumonias that start with some sort of viral illness and progress to a more serious lung infection. People who have underlying lung disease, who are cigarette smokers, who are elderly, or who use proton pump inhibitors are at higher risk for community-acquired pneumonias. Nonetheless, anyone could get a community-acquired pneumonia.
For someone who defines pneumonias based on the pathogen, then a community-acquired pneumonia is more likely to be a viral pneumonia. You need to know, however, that some people - physicians, respiratory therapists, some of the literature – doesn’t define pneumonia based on the pathogen, but on where the patient was when they got sick; i.e., where they were when they were exposed to whatever it was that caused this pneumonia. You may have a home health patient you are working with who has a known swallowing problem and gets pneumonia, and you are thinking, "Uh-oh, I think this could be aspiration related." Someone else might say, "No, this is a community-acquired pneumonia. The person was in the community when he got sick." So you have to know who is using the terms and how they are using them.
Nosocomia/healthcare-associated pneumonia. Then there is nosocomial pneumonia, which is also sometimes called healthcare-acquired, healthcare-associated, or hospital-associated pneumonia. If you are someone who defines pneumonia based on pathogen, then these are bacterial pneumonias. These are usually staph infections, sometimes due to Methicillin-resistant Staphylococcus aureus (MRSA). There are bacteria in healthcare environments, and if you put unhealthy people together in a place where there are a lot of bacteria, people get sick. If you are intubated, bed-dependent, elderly, weak, or debilitated, you are certainly at a higher risk.
But there are also folks who define nosocomial pneumonia or hospital-associated pneumonia based on where the patient was. You may have a patient in your hospital who had a stroke a couple of days ago who now has a new dysphagia and pneumonia and you think, "Oh, this could be aspiration-related." Someone else might say, "No, this is a nosocomial pneumonia; she was in the hospital when she got sick." To further complicate matters, we are also starting to see terms like community-acquired aspiration pneumonia and nosocomial aspiration pneumonia. So again, it is important to know how the people around you - the physicians, the respiratory therapists - are using these terms, so that everybody in your facility, at least, is on the same page.
Ventilator-associated pneumonia (VAP). There is also a subgroup of nosocomial pneumonias called ventilator-associated pneumonias because people who are ventilator-dependent are certainly at high risk. The longer you are on the vent, the higher your risk. If you are being tube-fed, or have known reflux disease, your risk is higher. If you are not awake and alert, and/or have a Glasgow Coma Scale score of less than nine, your risk is higher.
The issue, certainly with the VAPs, and with a lot of nosocomial pneumonias in general, is the biofilm. Within 24 to 48 hours of that sterile tubing being ripped open, it is covered with bacteria. We do our best to keep everything as clean as we can, but there are just a lot of bacteria in the world, and they are drawn to warm, wet places like airways, tracheostomy tubes, vent tubing, gastrostomy tubes, and that sort of thing.
Where is all this bacteria coming from? Some of it is just in the air in our healthcare environments. It is probably best not to think too much about it or you might not get out of the car in the morning. But, the fact remains that there are a lot of bacteria in healthcare environments. Some of it comes from the patients’ mouths. We all have bacteria in our mouths, and if we are not doing a good job of getting rid of it on a regular basis, it migrates to the tubing. Some of it is in the patients' stomachs. We all have bacteria in our stomachs, most of which serve a very important purpose in terms of digestion. But remember that we saw reflux disease as a risk factor for VAPs. There are folks who are refluxing material that contains stomach bacteria, and that can then be aspirated or migrate to the tubing. You could see how that might result in infection.
I mentioned that this terminology issue is a problematic one. A couple of years ago, there was a joint report that came out from the Infectious Disease Society of America and the American Thoracic Society, and they actually recommended removing the concept of healthcare-associated pneumonia from our lexicon. That does not seem to have happened in my neck of the woods quite yet. They want to talk about VAPs and hospital-acquired pneumonias as separate entities rather than lumping them all together under this concept of healthcare-associated pneumonias because they are caused by different organisms and require different treatment.
Stroke-associated pneumonia. To complicate matters, we are also starting to see the term stroke-associated pneumonia. We know there is a high incidence of pneumonia in stroke patients, and that is generally thought to be aspiration-related. But that may not be the entire explanation. When we compare dysphagia patients in general to stroke patients with dysphagia, patients who have stroke-related dysphagia have a higher incidence of pneumonia. Is there something special about their dysphagia that makes them aspirate more frequently? We also know that most of the pneumonias in patients who have had a stroke occur in the acute phases, during the first few days and weeks; in other words, in the presence of maximum neurological deficit. All of this has begged the question, is something else going on? Is this not just about aspiration?
This idea of stroke-associated pneumonia may be multifactorial. There could be some aspiration happening related to a new dysphagia. But we also know that immunodepression often accompanies a new stroke. Therefore, even a small amount of aspiration may be more likely to result in illness in patients with stroke, compared to patients with non-stroke-related dysphagia because their immune system is more compromised, particularly in the early days of the stroke.
There is also some neuronal excitotoxicity that occurs when stroke patients are sick, particularly if they have a fever. Fever seems to have the potential to worsen the neurological deficit, to worsen the effects of stroke. The oral flora - the bacteria in the mouth - is different after a stroke. There is increased colonization in general, probably related to the immune suppression. There are also changes in the bacteria type. The type of bacteria that patients with new stroke have in their mouths is much more virulent; so if aspirated, it is much more likely to result in illness.
Aspiration pneumonia. Finally, there is aspiration pneumonia which comes about as the result of aspiration of food, secretions, liquids, or gastric contents. Aspiration of reflux is an important and frequent cause of aspiration pneumonia. Many aspiration pneumonias are caused not by aspiration of food and liquid, but by aspiration of refluxed material.
The pathogens involved here are often polymicrobial; that is, more than one bug. There is more than one type of bug in our oral secretions, in the refluxed material, or in the food or liquid that we may have aspirated, so it is harder to pinpoint a single pathogen in aspiration pneumonias.
We cannot use chest x-rays to differentiate between types of pneumonias. No radiologist can look at a chest x-ray and say, "Oh, see that, that is definitely community-acquired" or “Look at that. That is clearly aspiration." But what physicians are looking for are infiltrates in the gravity-dependent portions of the lung because gravity is going to take that aspirated material as low as it will go. That is why lower lobe pneumonias are more suspicious for aspiration pneumonias. As for right side versus left side being more suspicious for aspiration, that generally does not play out. There is no evidence to support that one side or the other might be more or less likely to be aspiration-related. But the idea of lower lobe pneumonias being more suspicious does seem to be borne out in the literature.