Pneumonia is an infection that affects one or both lungs. It causes the air sacs, or alveoli, of the lungs to fill up with fluid or pus. Bacteria, viruses, or fungi may cause pneumonia. Symptoms can range from mild to serious and may include a cough with or without mucus (a slimy substance), fever, chills, and trouble breathing. How serious your pneumonia is depends on your age, your overall health, and what is causing your infection.
To diagnose pneumonia, your doctor will review your medical history, perform a physical exam, and order diagnostic tests such as a chest X-ray. This information can help your doctor determine what type of pneumonia you have.
Treatment for pneumonia may include antibiotics or viral or fungal medicines. It may take several weeks to recover from pneumonia. If your symptoms get worse, you should see a doctor right away. If you have severe pneumonia, you may need to go to the hospital for antibiotics given through an intravenous (IV) line and oxygen therapy.
Explore this Health Topic to learn more about pneumonia, our role in clinical trials, and where to find more information.
Most of the time your body filters germs out of the air that you breathe. Sometimes germs, such as bacteria, viruses, or fungi, get into your lungs and cause infections.
When these germs get into your lungs, your immune system, which is your body's natural defense against germs, goes into action. Immune cells attack the germs and may cause inflammation of your air sacs, or alveoli. Inflammation can cause your air sacs to fill up with fluid and pus and cause the symptoms of pneumonia. Watch the video below to learn more. You can also learn more about How the Lungs Work in our Health Topic.
This video shows how your immune system tries to get rid of germs in your respiratory system and how you develop pneumonia. Medical Animation Copyright © 2020 Nucleus Medical Media Inc. All rights reserved.
Bacteria are a common cause of pneumonia in adults. Many types of bacteria can cause pneumonia, but Streptococcus pneumoniae (also called pneumococcus bacteria) is the most common cause in the United States.
Some bacteria cause pneumonia with different symptoms or other characteristics than “typical” pneumonia. This infection is called atypical pneumonia. For example, Mycoplasma pneumoniae causes a mild form of pneumonia often called “walking pneumonia.” Legionella pneumophila causes a severe type of pneumonia called Legionnaires’ disease. Bacterial pneumonia can happen on its own or develop after you have had a cold or the flu.
Viruses that infect your lungs and airways can cause pneumonia. The flu (influenza virus) and the common cold (rhinovirus) are usually the most common causes of viral pneumonia in adults. Respiratory syncytial virus (RSV) is the most common cause of viral pneumonia in young children.
Many other viruses can cause pneumonia, including SARS-CoV-2, the virus responsible for COVID-19. Watch our video on how SARS-CoV-2 affects the lungs to learn more. Additionally, we offer information and resources on how we are working hard to support necessary COVID-19 research.
Fungi such as Pneumocystis jirovecii may cause pneumonia, particularly in people who have weakened immune systems. Some fungi found in the soil in the southwestern United States and in the Ohio and Mississippi River valleys can cause pneumonia.
Your risk of pneumonia may be higher because of your age, environment, lifestyle habits, and other medical conditions.
Pneumonia can affect people of all ages. However, two age groups are at higher risk of developing pneumonia and having more serious pneumonia.
Babies, children, and older adults who do not get the recommended vaccines to prevent pneumonia have an even higher risk.
Most people get pneumonia when they catch an infection from someone else in their community. Your chance of getting pneumonia is higher if you live or spend a lot of time in a crowded place such as a military barrack, prison, homeless shelter, or nursing home.
Your risk is also higher if you regularly breathe in air pollution or toxic fumes.
Some germs that cause pneumonia can infect birds and other animals. You are most likely to encounter these germs if you work in a chicken or turkey processing center, pet shop, or veterinary clinic.
You may have an increased risk of pneumonia if you have any of the following medical conditions.
Pneumonia can be very serious and even life-threatening. Vaccines can help prevent some types of pneumonia. Good hygiene (washing your hands often), quitting smoking, and keeping your immune system strong by getting regular physical activity and eating healthy are other ways to lower your risk of getting pneumonia.
Vaccines can help prevent pneumonia caused by pneumococcus bacteria or the flu virus. Vaccines cannot prevent all cases of pneumonia. However, compared to people who don't get vaccinated, those who are vaccinated and still get pneumonia tend to have:
Two vaccines are available to prevent infections from the pneumococcus bacteria, the most common type of bacteria that causes pneumonia. Pneumococcus vaccines are especially important for people at high risk of pneumonia, including:
For more information, visit the CDC’s Pneumococcal Vaccination and Pneumococcal Vaccination: Summary of Who and When to Vaccinate pages.
Flu (influenza) vaccine
Your yearly flu vaccine can help prevent pneumonia caused by the flu. The flu vaccine is usually given in September through October, before flu season starts.
Haemophilus influenzae type b (Hib) is a type of bacteria that can cause pneumonia and meningitis. The Hib vaccine is recommended for all children under 5 years old in the United States. The vaccine often is given to infants starting when they are 2 months old.
For more information about the Hib vaccine, go to the CDC's Hib Vaccination webpage.
You can take the following steps to help prevent pneumonia:
The signs and symptoms of pneumonia can be mild or serious. Young children, older adults, and people who have serious health conditions are at risk for developing more serious pneumonia or life-threatening complications.
The signs and symptoms of pneumonia may include:
You may also have other symptoms, including a headache, muscle pain, fatigue (extreme tiredness), nausea (feeling sick to your stomach), vomiting, and diarrhea.
Older adults and people who have serious illnesses or weakened immune systems may not have typical symptoms. They may have a lower than normal temperature instead of a fever. Older adults who have pneumonia may feel weak or suddenly confused.
Sometimes babies don’t have typical symptoms either. They may vomit, have a fever, cough, or appear restless or tired and without energy. Babies may also show the following signs of breathing problems:
Often, people who have pneumonia can be successfully treated and do not have complications. Complications from pneumonia are more common in children, older adults, and people with other serious diseases.
This video describes complications that can happen from pneumonia. Read below for a more complete list of possible complications. Medical Animation Copyright © 2020 Nucleus Medical Media Inc. All rights reserved.
Complications of pneumonia that may be life-threatening include:
Your doctor will diagnose pneumonia based on your medical history, a physical exam, and test results. Sometimes pneumonia is hard to diagnose because your symptoms may be the same as a cold or flu. You may not realize that your condition is more serious until it lasts longer than these other conditions.
During your physical exam, your doctor will check your temperature and listen to your lungs with a stethoscope.
If your doctor thinks you have pneumonia, he or she may do one or more of the following tests.
If you are in the hospital, have serious symptoms, are older, or have other health problems, your doctor may do other tests to diagnose pneumonia.
Treatment for pneumonia depends on your risk factors and how serious your pneumonia is. Many people who have pneumonia are prescribed medicine and recover at home. You may need to be treated in the hospital or an intensive care unit (ICU) if your pneumonia is serious.
Your doctor may prescribe some of the following medicines to treat your pneumonia at home or at the hospital, depending on how sick you are.
Management at home
If your pneumonia is mild, your doctor may prescribe medicines or suggest over-the-counter medicines to treat it at home.
Management at the hospital
If your pneumonia is serious, you may be treated in a hospital to get antibiotics and fluids through an intravenous (IV) line inserted into your vein and to get oxygen therapy to increase the amount of oxygen in your blood. If your pneumonia is very serious, you may need to be put on a ventilator.
Your healthcare team may need to perform a procedure or surgery to remove seriously infected or damaged parts of your lung. This may help you recover and may prevent your pneumonia from coming back.
If you are diagnosed with pneumonia, it is important to follow your treatment plan, take steps to help your body recover, monitor your condition, and take steps to prevent your infection from spreading to others.
It may take time to recover from pneumonia. Some people feel better and are able to return to their normal routines in one to two weeks. For others, it can take a month or longer. Most people continue to feel tired for about a month. Talk with your doctor about when you can return to your normal activities. Watch the video below to learn about managing your recovery at home.
This video shows what to expect as you recover from pneumonia and how you can improve your recovery. Medical Animation Copyright © 2020 Nucleus Medical Media Inc. All rights reserved.
It is important that you take all your medicines as your doctor prescribes. If you are using antibiotics, continue to take the medicine until it is all gone. You may start to feel better before you finish the medicine, but you should continue to take it. If you stop too soon, the bacterial infection and your pneumonia may come back. It may also become resistant to the antibiotic, making treatment more difficult.
The following steps can help your body recover from pneumonia.
Ask your doctor when you should schedule follow-up care. If your symptoms have not improved, your doctor may use a chest X-ray to help diagnose other conditions that may be causing your symptoms.
Your doctor may suggest pulmonary rehabilitation to help you breathe better as your lungs recover. You may also need physical therapy to help you regain your strength. Physical activity can help improve your recovery.
Pneumonia can have long-term effects such as depression, and worsening heart and blood vessel diseases. Call your doctor if you develop these conditions, if your symptoms suddenly get worse, or if you have trouble breathing or talking.
The following steps can help you prevent spreading the infection to others around you.
Some people get pneumonia again and again. Tell your doctor if this happens. Return to Prevention to find more strategies to help prevent pneumonia.