Pneumonia: What Lurks in the Lungs
Jan 6, 2004
Now that fear of the flu has reached SARS-like proportions, it’s time to remember that influenza season is also pneumonia season. In fact, some pneumonias can be caused by the flu, or follow an influenza infection. Pneumonia is an infection of the lungs that most commonly affects older people but can also affect children and younger adults. While pneumonia caused about 62,000 deaths in the United States in 2001, it can usually be treated with antibiotics.
And a preventative vaccine exists for pneumococcal pneumonia, the most common type of pneumonia. But like the flu vaccine, this year there is a limited supply of pneumococcal conjugate vaccine.
Below, pneumonia researcher Michael Fine, M.D., a professor of medicine at the University of Pittsburgh and director of the VA-Pittsburgh Center for Health Equity Research and Promotion, discusses the different types of pneumonia and why prevention or early treatment is best.
What is pneumonia?
It’s an infection of the respiratory tract that is typically characterized by a broad array of signs and symptoms. The infection is usually termed community-acquired pneumonia to differentiate it from that acquired in the hospital.
The lungs are comprised of very tiny sacs called alveoli. This is where the oxygen that we inhale comes into contact with circulating blood through capillaries, or tiny blood vessels, and where the oxygen is exchanged. In pneumonia, those tiny sacs become filled up with infectious material.
Who is at highest risk for pneumonia?
Among adults, risk increases with age. So the older you are, the greater the likelihood to get pneumonia. If you’re a smoker, you have a slightly greater increased risk because smoking diminishes the lung’s capacity to fight infection.
Anyone who is a drug abuser or an alcoholic, who has impaired levels of consciousness that can affect the gag reflex, would be at increased risk because they can inhale their own throat secretions. Patients who are immunocompromised for one reason or another, whether they’re taking systemic corticosteroids for something like asthma or if they’re receiving chemotherapy or radiation therapy for cancer, would be at increased risk.
What are common symptoms?
The symptoms can really be divided into two categories: typical respiratory symptoms and nonrespiratory symptoms. Respiratory symptoms would include cough, coughing up mucus, shortness of breath and chest pain. A less common respiratory symptom would be coughing up blood.
Then there are a variety of nonrespiratory symptoms, the most common of whichÃƒÂ¯Ã‚Â¿Ã‚Â½and probably the number-one symptom overallÃƒÂ¯Ã‚Â¿Ã‚Â½is fatigue, which is present in about 90 percent of patients. You can also get headache, muscle aches, abdominal pain, fever and chills.
And, it’s possible to be asymptomatic, but quite unlikely. But frequently, in the elderly, the symptoms are subtle. For example, patients who are older may not have a severe temperature. They also may have more atypical symptoms, such as abdominal pain, rather than classic pulmonary symptoms.
What is meant by walking pneumonia?
That’s a lay term and it refers to a mild case, perhaps in a younger person, that can safely be treated in the outpatient setting.
What causes pneumonia?
We usually think of infectious causes and, within that category, there are both bacteria and viruses. In adults we think bacteria first because it’s more prevalent.
Within the types of bacteria, there are the bacterium called Streptococcus pneumonia, which causes pneumococcal pneumonia, and then there’s one called Haemophilus influenzae. These are probably the first and second-most common causes. Haemophilus influenzae may be more common in smokers and patients who have underlying chronic emphysema or bronchitis.
Viruses probably account for 20 percent to 25 percent of community-acquired pneumonia in adults. And in children, there’s a much greater likelihood that the pneumonias are caused by a virus than a bacteria.
The influenza virus can cause pneumonia, though not frequently. And following influenza, patients also become more susceptible to developing bacterial pneumonia.
And then there are a variety of less common organisms that cause pneumonia such as Mycoplasma, Legionella and Chlamydia. There are many other causes that are probably infectious but we can’t uncover what the actual agent is.
Is it possible to have the bacterial and viral pneumonias at the same time?
Yes, it’s possible to have bacteria and a virus or two types of bacteria at one time. Probably 10 percent to 15 percent of infections are due to that type of bacterial co-infection.
Do the symptoms vary depending on the types of pneumonia you have?
Traditional wisdom said yes, but in fact when people have looked at that, it’s really impossible to differentiate the cause of the pneumonia based on the symptoms.
How is pneumonia usually diagnosed?
The diagnosis requires the presence of some of the clinical symptoms. And then in adults, the gold standard is to obtain a chest X-ray and to find a shadow called an infiltrate on the chest X-ray.
When you take an X-ray of the lungs, usually the air shows up as a very dark, almost black, space on the chest X-ray. When the lungs become filled up with this infectious material, it looks white on the X-ray and that’s what’s called the infiltrate.
Do you think that chest X-rays are being done as often as they should be?
Unfortunately, if you’re a physician practicing in the community, particularly in a rural setting, there may not be access to X-rays. So I think there may be a tendency in certain parts of the country to treat with antibiotics based on symptoms without ever formally establishing the diagnosis. So I think we may be under-utilizing chest X-rays to make the diagnosis.
How is pneumonia spread?
Most cases of pneumonia that are bacterial in origin are not necessarily transmitted from person to person. These bacteria actually reside in people’s normal respiratory tract systems: in their throats, their pharynx, their nose. Everybody has a small content of material from the throat that gets into the lungs, and then normally the person’s defense mechanism sweeps that out. But sometimes the body isn’t able to defend against that and that’s when the infection starts.
Some types of viral pneumonia, however, can be transmitted by droplets, so if you cough or breathe on someone, they are transmittable. But most cases of bacterial pneumonia are not passed from person to person that way.
How is pneumonia treated?
In adults, it’s typically treated with antibiotics. For patients who are healthy enough to be treated in their own homes, usually we treat them for seven to 10, sometimes up to 14 days with antibiotics by mouth.
About one million of the four million cases nationally require hospitalization. Patients in the hospital typically get a course of intravenous antibiotics. The duration of that course of intravenous antibiotics really depends upon their response to therapy. Once their vital signs begin to normalize and their temperature begins to come down and they have adequate oxygen in their blood, then we switch them from intravenous to oral antibiotic therapy.
What happens if pneumonia isn’t treated?
What happened before the advent of penicillin and antibiotics is that many patients got better without treatment. But those who were immunocompromised or either aged or very young or frail often died from pneumonia. Even now, with antibiotics, the average mortality rate is probably somewhere between 5 percent and 15 percent.
The average age of an adult with pneumonia is in the 60s. So many of these patients have additional underlying medical illnesses that pneumonia often makes worse.
For example, if the oxygen doesn’t reach the tissues and someone has heart disease, it can lead to cardiac complications. People with pneumonia can also develop secondary respiratory failure and respiratory complications and complications of their kidneys or their liver.
How long is someone usually sick with pneumonia?
We actually have done long-term studies and found that patients may still be fatigued a month later. And probably a quarter to a half of patients may even be fatigued up to 90 days or more.
How is pneumonia prevented?
There are several ways to prevent pneumonia. Number one is to try to get people to stop smoking. Number two, there are several vaccines, specifically the flu vaccine, because during flu season the incidence of pneumonia goes up because you can have a post-influenza bacterial infection.
There’s a vaccine against pneumococcus, the number-one cause of pneumonia in adults. And that’s generally recommended for patients who are over the age of 65 or higher-risk patients, patients who would be immunocompromised for one reason or another who are less than age 65.
Are many pneumonias resistant to antibiotics?
One of the things that we have to be concerned about in this country is the overuse of antibiotics. One of the reasons that it’s so important to establish an accurate diagnosis of pneumonia is that for many other things that mimic pneumonia such as bronchitis, there’s no good evidence that antibiotics improve patient’s outcomes. But they do increase resistance to certain organisms.
In this country, over the past 10 to 15 years, we’ve seen a tremendous growth in resistance among Streptococcus pneumoniae or pneumococcus, the number-one cause, as well as Haemophilus influenzae, to penicillin and cephalosporin types of antibiotics that were traditionally used to treat these types of infection.
Do you see any solution to this problem?
The solution is to try to make an accurate diagnosis, and only treat infections when you’ve made an accurate diagnosis. We do have newer, stronger antibiotics that are available now that can be used for those situations. But it’s hard to know ahead of time when a patient will be infected with a resistant strain.
At what point should someone go to the doctor or the emergency room?
Anyone who has a cough-related illness with fever or shaking chills; anyone who has a cough-related illness with symptoms of wheezing or shortness of breath; and anyone who has a cough-related illness with or without fever who’s immunocompromised, extremely elderly, or pregnant, should be in touch with their doctor.