Information for Patients
What is pneumonia?
Pneumonia is an infection in one or both of the lungs. It causes the air sacs of the lungs to fill up with fluid or pus. It can range from mild to severe, depending on the type of germ causing the infection, your age, and your overall health.
What causes pneumonia?
Bacterial, viral, and fungal infections can cause pneumonia.
Bacteria are the most common cause. Bacterial pneumonia can occur on its own. It can also develop after you've had certain viral infections such as a cold or the flu. Several different types of bacteria can cause pneumonia, including:
- Streptococcus pneumoniae
- Legionella pneumophila; this pneumonia is often called Legionnaires' disease
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Haemophilus influenzae
Viruses that infect the respiratory tract may cause pneumonia. Viral pneumonia is often mild and goes away on its own within a few weeks. But sometimes it is serious enough that you need to get treatment in a hospital. If you have viral pneumonia, you are at risk of also getting bacterial pneumonia. The different viruses that can cause pneumonia include:
- Respiratory syncytial virus (RSV)
- Some common cold and flu viruses
- SARS-CoV-2, the virus that causes COVID-19
Fungal pneumonia is more common in people who have chronic health problems or weakened immune systems. Some of the types include:
- Pneumocystis pneumonia (PCP)
- Coccidioidomycosis, which causes valley fever
Who is at risk for pneumonia?
Anyone can get pneumonia, but certain factors can increase your risk:
- Age; the risk is higher for children who are age 2 and under and adults age 65 and older
- Exposure to certain chemicals, pollutants, or toxic fumes
- Lifestyle habits, such as smoking, heavy alcohol use, and malnourishment
- Being in a hospital, especially if you are in the ICU. Being sedated and/or on a ventilator raises the risk even more.
- Having a lung disease
- Having a weakened immune system
- Have trouble coughing or swallowing, from a stroke or other condition
- Recently being sick with a cold or the flu
What are the symptoms of pneumonia?
The symptoms of pneumonia can range from mild to severe and include:
- Cough, usually with phlegm (a slimy substance from deep in your lungs)
- Shortness of breath
- Chest pain when you breathe or cough
- Nausea and/or vomiting
The symptoms can vary for different groups. Newborns and infants may not show any signs of the infection. Others may vomit and have a fever and cough. They might seem sick, with no energy, or be restless.
Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower than normal temperature. Older adults who have pneumonia sometimes have sudden changes in mental awareness.
What other problems can pneumonia cause?
Sometimes pneumonia can cause serious complications such as:
- Bacteremia, which happens when the bacteria move into the bloodstream. It is serious and can lead to septic shock.
- Lung abscesses, which are collections of pus in cavities of the lungs
- Pleural disorders, which are conditions that affect the pleura. The pleura is the tissue that covers the outside of the lungs and lines the inside of your chest cavity.
- Kidney failure
- Respiratory failure
How is pneumonia diagnosed?
Sometimes pneumonia can be hard to diagnose. This is because it can cause some of the same symptoms as a cold or the flu. It may take time for you to realize that you have a more serious condition.
Your health care provider may use many tools to make a diagnosis:
- A medical history, which includes asking about your symptoms
- A physical exam, including listening to your lungs with a stethoscope
- Various tests, such as
- A chest x-ray
- Blood tests such as a complete blood count (CBC) to see if your immune system is actively fighting an infection
- A Blood culture to find out whether you have a bacterial infection that has spread to your bloodstream
If you are in the hospital, have serious symptoms, are older, or have other health problems, you may also have more tests, such as:
- Sputum test, which checks for bacteria in a sample of your sputum (spit) or phlegm (slimy substance from deep in your lungs).
- Chest CT scan to see how much of your lungs is affected. It may also show if you have complications such as lung abscesses or pleural effusions.
- Pleural fluid culture, which checks for bacteria in a fluid sample that was taken from the pleural space
- Pulse oximetry or blood oxygen level test, to check how much oxygen is in your blood
- Bronchoscopy, a procedure used to look inside your lungs' airways
What are the treatments for pneumonia?
Treatment for pneumonia depends on the type of pneumonia, which germ is causing it, and how severe it is:
- Antibiotics treat bacterial pneumonia and some types of fungal pneumonia. They do not work for viral pneumonia.
- In some cases, your provider may prescribe antiviral medicines for viral pneumonia
- Antifungal medicines treat other types of fungal pneumonia
You may need to be treated in a hospital if your symptoms are severe or if you are at risk for complications. While there, you may get additional treatments. For example, if your blood oxygen level is low, you may receive oxygen therapy.
It may take time to recover from pneumonia. Some people feel better within a week. For other people, it can take a month or more.
Can pneumonia be prevented?
Vaccines can help prevent pneumonia caused by pneumococcal bacteria or the flu virus. Having good hygiene, not smoking, and having a healthy lifestyle may also help prevent pneumonia.
NIH: National Heart, Lung, and Blood Institute
General Equivalence Map Definitions
The ICD-9 and ICD-10 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.
- Approximate Flag - The approximate flag is on, indicating that the relationship between the code in the source system and the code in the target system is an approximate equivalent.
- No Map Flag - The no map flag indicates that a code in the source system is not linked to any code in the target system.
- Combination Flag - The combination flag indicates that more than one code in the target system is required to satisfy the full equivalent meaning of a code in the source system.
Index of Diseases and Injuries Definitions
- And - The word "and" should be interpreted to mean either "and" or "or" when it appears in a title.
- Code also note - A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.
- Code first - Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- Type 1 Excludes Notes - A type 1 Excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- Type 2 Excludes Notes - A type 2 Excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- Includes Notes - This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- Inclusion terms - List of terms is included under some codes. These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
- NEC "Not elsewhere classifiable" - This abbreviation in the Alphabetic Index represents "other specified". When a specific code is not available for a condition, the Alphabetic Index directs the coder to the "other specified” code in the Tabular List.
- NOS "Not otherwise specified" - This abbreviation is the equivalent of unspecified.
- See - The "see" instruction following a main term in the Alphabetic Index indicates that another term should be referenced. It is necessary to go to the main term referenced with the "see" note to locate the correct code.
- See Also - A "see also" instruction following a main term in the Alphabetic Index instructs that there is another main term that may also be referenced that may provide additional Alphabetic Index entries that may be useful. It is not necessary to follow the "see also" note when the original main term provides the necessary code.
- 7th Characters - Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
- With - The word "with" should be interpreted to mean "associated with" or "due to" when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List. The word "with" in the Alphabetic Index is sequenced immediately following the main term, not in alphabetical order.