Pneumonia is an infection in one or both of the lungs. Many small germs such as bacteria, viruses, and fungi, can cause pneumonia. The infection causes your lungs' air sacs, called alveoli, become inflamed. The air sacs may fill up with fluid or pus, causing symptoms such as cough with phlegm, fever, chills, and trouble breathing.


Pneumonia and its symptoms can vary from mild to severe. Many factors affect how serious pneumonia is, such as the type of germ causing the infection and your age and overall health.

Pneumonia tends to be more serious for the following:
  • Infants and young children
  • People 65 years or older
  • People who have other health problems (examples: heart failure, diabetes, COPD)
  • People who have weak immune systems as a result of diseases or other factors (examples: HIV/AIDS, chemotherapy, organ/bone marrow transplant).

Pneumonia is common in the U.S. Treatment for pneumonia depends on its cause, how severe your symptoms are, and your age and overall health. Many people can be treated at home, often with oral antibiotics. Anyone whose symptoms get worse should be checked by a doctor. People who have more severe symptoms or underlying health problems may need treatment in a hospital.


Pneumonia is named for the way in which a person gets the infection or for the germ that causes it. Many people may not realize that there are different types of pneumonia. The following are types of pneumonia:
  • Community-Acquired Pneumonia (CAP) - occurs outside of hospitals and other health care settings. It is the most common type of pneumonia. Most cases occur during winter. Most people get CAP by breathing in germs that live in the mouth, nose, or throat.
  • Hospital-Acquired Pneumonia (HAP) - occurs when people catch pneumonia during a hospital stay. People on a machine that helps them breathe (mechanical ventilator) is at a higher risk for getting HAP. Also, HAP tends to be more serious than CAP. This is because you're already sick.
  • Health Care-Associated Pneumonia - occurs when a patient catch a pneumonia in other health care settings, such as nursing homes, dialysis centers, and outpatient clinics.
  • Aspiration Pneumonia - a type of pneumonia that occurs when you accidentally inhale food, drink, vomit, or saliva from your mouth into your lungs. This usually happens when something disturbs your normal gag reflex, such as a brain injury, swallowing problem, or excessive use of alcohol or drugs. Aspiration pneumonia can cause pus to form in a cavity in the lung, called a lung abscess.
  • Atypical Pneumonia - several types of bacteria (examples: legionella pneumophila, mycoplasma pneumonia, chlamydophila pneumoniae) cause this type of CAP. Atypical pneumonia is passed from person to person.

Many different germs can cause pneumonia. These include different kinds of bacteria, viruses, and, less often, fungi. Most of the time, the body filters germs out of the air that we breathe to protect the lungs from infection. Sometimes, though, germs manage to enter the lungs and cause infections. This is more likely to occur when:
  • Your immune system is weak.
  • A germ is very strong.
  • Your body fails to filter germs out of the air that you breathe.

Pneumonia can affect people of all ages. However, two age groups are at greater risk of developing pneumonia:
  • Infants who are 2 years or younger, because their immune systems are still developing during the first few years of life.
  • Adults who are 65 years or older.
  • If you have a lung disease or other serious disease (examples: cystic fibrosis, asthma, COPD, bronchiectasis, diabetes, heart failure, sickle cell anemia).
  • If you're in a hospital ICU, especially if you're on a ventilator ( a machine to help you breathe).
  • If you have a weak or depressed immune system (examples: HIV/AIDS, organ/bone marrow transplant, chemotherapy, long-term steroid use).
  • If you have trouble coughing because of a stroke, trouble swallowing, limited ability to move, alcohol use, or sedation (being given medicine to make you relaxed or sleepy).
  • Smoking cigarettes, abusing alcohol, being undernourished.
  • If you've recently had a cold or the flu.
  • If you're exposed to certain chemicals, pollutants, or toxic fumes.

The symptoms of pneumonia vary from mild to severe. Many factors affect how serious pneumonia is, including the type of germ causing the infection and your age and overall health.

See your doctor promptly if you:
  • Have a high fever.
  • Have shaking chills.
  • Have a cough with phlegm, which doesn't improve or worsens.
  • Develop shortness of breath with normal daily activities.
  • Have chest pain when you breathe or cough.
  • Feel suddenly worse after a cold or the flu.
  • Have other symptoms including nausea (feeling sick to your stomach), vomiting, and diarrhea.

Often, people who have pneumonia can be treated successfully and not have complications. But some patients, especially those in high-risk groups, may have complications such as the following:
  • Bacteremia - this serious complication occurs when the infection moves into your bloodstream. From there, it can quickly spread to other organs, including your brain.
  • Lung abscess - an abscess occurs when pus forms in a cavity in the lung. An abscess is usually treated with antibiotics. In some cases, surgery or needle drainage is needed to remove it.
  • Pleural effusion - pneumonia may cause fluid to build up in the pleural space, which is the space between your lungs and chest wall. Pneumonia can cause the fluid to become infected- a condition called empyema. If this happens, you may need to have the fluid drained through a chest tube or removed through surgery.

Pneumonia can be hard to dignose because it may seem like a cold or flu. Your doctor will diagnose pneumonia based on your medical history and the results from a physical exam and tests.


If your doctor suspects you have pneumonia, he or she may order one or more of the following tests:
  • Chest x-ray.
  • Blood tests (examples: Complete Blood Count (CBC), Blood culture).
  • Sputum test.
  • Chest CT scan.
  • Pleural fluid culture
  • Pulse oximetry.
  • Bronchoscopy.

Treatment for pneumonia depends on the type of pneumonia you have and how severe it is. The goals of treatment are to cure the infection and prevent complications.

For bacterial pneumonia - it is treated with antibiotics. You should take antibiotics as your doctor prescribes. You may start to feel better before you finish the medicine, but you should continue taking it as prescribed. If you stop too soon, the pneumonia may come back.

For viral pneumonia - it is not treated with antibiotics. This type of medicine doesn't work when a virus causes the pneumonia. If you have viral pneumonia, your doctor may prescribe an antiviral medicine to treat it.

If the level of oxygen in your bloodstream is low, you may receive oxygen. If you have bacterial pneumonia, your doctor may give you antibiotics through an intravenous (IV) line inserted into a vein.

  • Vaccines (examples: pneumococcal pneumonia vaccine, influenza vaccine, Hib vaccine).
  • Wash your hands with soap and water or alcohol-based rubs to kill germs.
  • Don't smoke. Smoking damages your lungs' ability to filter out and defend against germs.
  • Keep your immune system strong. Get plenty of rest and physical activity and follow a healthy diet.
If you have pneumonia, limit contact with family and friends. Cover your nose and mouth while coughing or sneezing, and dispose of tissues right away. These measures help keep the infection from spreading.