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  • Writer's pictureP.K. Peterson

Pneumonia: What Every Adult Needs to Know

“Unfortunately, community-acquired pneumonia is a neglected, but common medical event; the lack of a sense of emergency within the general public, little economic investment at a public and private level, and absence of advocacy and disease awareness are worrisome.”

- Stefano Alberti, M.D., Department of Biomedical Sciences, Humanitas University, Italy

Pneumonia may well be called the friend of the aged. Taken off by it an acute, short, not often painful illness, the old man escapes those ‘cold gradations of decay’ so distressing to himself and to his friends.”

- Sir William Osler, Canadian physician and a founding professor of Johns Hopkins Hospital




Pneumonia is the leading cause of infection-related deaths in the U.S. and the single largest infectious cause of death in children worldwide. As a comprehensive review of pneumonia in a Germ Gems post is impossible, in this week’s post I address only what every adult needs to know about pneumonia and also highlight several new developments in the management of the disease.

What is pneumonia, and how do I know if I have it? Pneumonia is an infection of the lower respiratory tract (the lungs) caused by a wide variety of microbes (bacteria, fungi, viruses, and parasites). Most of these pathogens cause similar symptoms and signs of the infection. They are: cough, shortness of breath, sharp chest pain when breathing in (pleuritic pain), increased respiratory rate (over 20 breaths per minute), and fever. But some of these pathogens, namely the bacteria Streptococcus pneumoniae (called the “captain of the men of death” by Sir William Osler), Staphylococcus aureus, andLegionella (the cause of Legionnaire’s disease), are notorious for causing more serious, rapidly progressing, and life-threatening disease.

If you have any combination of the above symptoms, your suspicion of pneumonia should be piqued. But there is no way for you to tell whether you are suffering from an upper or a lower respiratory tract infection. Only your health care provider can make this determination.


Your physician will thoroughly examine you, including listening to your breath sounds with a stethoscope. If “crackles” are heard on exam or other worrisome features are noted, for example, your cough is productive of blood (hemoptysis), then a chest x-ray or, in some cases, a chest CT scan should be ordered. If the radiographic test shows infiltrates—white areas in the lungs that are indicative an infection, you have pneumonia.


If my clinical picture and chest x-ray are compatible with a diagnosis of pneumonia, what’s next? Now your health care provider must determine the etiological cause of your pneumonia. This can be challenging.


Your medical history (your age, the status of your immune system—immunocompromised patients are susceptible to opportunistic microbes—and exposure history—whether you are in the community, hospital, or nursing home or have traveled to certain areas) can point to the most likely pathogen. For example, recent travel to certain areas of China where an outbreak of Mycoplasma pneumoniae pneumonia is occurring or to Northern Argentina where an outbreak of Legionnaire’s disease is unfolding should raise suspicion of these pathogens as the cause of pneumonia.


The eruption of the COVID-19 pandemic in 2019, caused by the coronavirus SARS-CoV-2, underscored the importance of  “exposure history” in helping to determine the etiology of pneumonia. (A new SARS-CoV-2 variant, JN.1, is currently concerning many experts; See “New COVID Variant JN.1 Could Disrupt Holiday Plans,” in WebMD, December 7, 2023). At this time of year, two other viral causes of pneumonia need to be strongly considered: influenza virus and respiratory syncytial virus (RSV).


There are tests to determine the cause of pneumonia. Sputum culture and sputum Gram stain are two old tests for the disease. In my opinion, they are of little value. A blood culture can also be taken. If positive, it can establish the etiology. Most of the time, however, the blood culture is negative.

Fortunately, a new molecular test is now available. It is a rapid multiplex polymerase chain reaction (PCR) for respiratory viruses including SARS-CoV-2, influenza A, RSV, as well as 18 other common respiratory pathogens. In randomized clinical trials, this test has been shown to improve outcomes of inpatients with pneumonia. When a viral etiology is established with this test, antibiotic treatment is not needed.


If I’m diagnosed with pneumonia, where should I be treated and with what therapeutic agent(s)? If you are not in the hospital or a nursing home and develop pneumonia, you have what is called “community-acquired pneumonia” or CAP. About 20% of adults with CAP are treated as outpatients.

The decision whether you should be hospitalized, and if so, should it be to an intensive care unit, is based on your doctor’s assessment of the severity of your illness. In making this assessment, your physician will weigh a number of factors in the balance, e.g., your age, history of other underlying medical conditions, vital signs (blood pressure, respiratory rate, pulse, and temperature), blood oxygen saturation level under 95 by pulse oximetry, white blood cell count, and your mental status (confusion and somnolence are bad signs).


If the evidence suggests that you have bacterial pneumonia, then prompt administration of an antibiotic is in order. The choice of which drug to use, however, is a judgment call by your healthcare  provider. Often a broad spectrum agent is given initially, and when results of laboratory tests are known, changing to a more narrow spectrum drug is appropriate to help prevent emergence of multiply antibiotic- resistant bacteria.


A recent advance in the treatment of severe CAP is the administration of hydrocortisone. This drug dampens the inflammatory response elicited by infection in the lungs that can cause serious organ damage and even death (See“Hydrocortisone in Severe Community-Acquired Pneumonia,”  New England Journal of Medicine, May 25, 2023; “Efficacy and Safety of Corticosteroid Therapy for Community Required Pneumonia: A Meta-Analysis and Meta-Regression of Randomized Controlled Trials,” Clinical Infectious Diseases, October 26, 2023.)


Although the management of bacterial pneumonia receives most of the attention, viral pneumonia caused by SARS-CoV-2, influenza virus, and RSV can also be life-threatening. In the case of SARS-CoV-2 and influenza virus, antiviral drugs are given as soon as the diagnosis is considered. And for all three of these viral infections, vaccines are highly recommended to prevent pneumonia.

Postscript: Is pneumonia “an old person’s friend?” In the late 1800s, pneumonia was the leading cause of death for those over 65 years old and was popularly referred to as the “old person’s friend.” In the 1892 edition of the medical textbook, The Principles and Practice of Medicine, the preeminent physician and father of internal medicine Sir William Osler wrote that pneumonia is so fatal in the aged that it could be called “the natural end of the old man,” offering a quieter and more peaceful death compared to more painful illnesses. Osler himself died of pneumonia in 1919 at age 70.

Today, with the use of antibiotics and antivirals, pneumonia is superseded by heart disease and cancer as a cause of death in the aged population. It still, however, presents a great threat (and potential solace) to older adults, particularly those in hospitals or nursing homes.

In an August 20, 2023 article in MedPage Today, “The old man’s friend: Refuse antibiotics to achieve a peaceful death,” Althea Halchuk, founder of “Ending Well! Patient Advocacy,” makes a strong case for patients with terminal or severe debilitating illnesses “to stop all treatments, especially antibiotics.” In the article, she quotes hospice and palliative medicine physician Timothy Sullivan, M.D. who said, “But for some dying patients the greatest harm of antibiotic use may simply be to prevent a relatively quick and peaceful death; for those enduring intractable pain, or struggling to breathe, or slowly deteriorating in a hospital bed, an infection might bring a painless end to their ordeal.”

In my book Get Inside Your Doctor’s Head: 10 Commonsense Rules for Making Better Decisions about Medical Care, my tenth rule is: “Caring is always an important medicine.” This is the only rule that should never be broken. Within this context, caring for some patients with pneumonia may call for withholding antibiotic treatment allowing for nature to take its course. It is a difficult decision, but a caring one.


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Main Page images courtesy of Shuxian Hu, MD. Dr. Hu is a scientist in the Neuroimmunology Research Laboratory at the University of Minnesota.

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