Pneumonia is an inflammatory condition of the lung. It is often characterized as inflammation of the the alveoli and abnormal alveolar filling with fluid. The alveoli are microscopic air filled sacs in the lungs responsible for exchanging carbon dioxide for oxygen.

You can get community-associated pneumonia in your daily life, such as at school or work. Healthcare-associated pneumonia is contracted when you are in a hospital or nursing home. This type of pneumonia may be more severe because you already are ill.

Germs called bacteria or viruses usually cause pneumonia. Pneumonia usually starts when you breathe the germs into your lungs. You may be more likely to get the disease after having a cold or the flu. These illnesses make it hard for your lungs to fight infection, so it is easier to get pneumonia. Other risk factors include:

• Asthma
• Heart disease
• Cancer
• Diabetes

Symptoms of pneumonia caused by bacteria usually come on quickly. They may include:

• Cough. You will likely cough up mucus (sputum) from your lungs. Mucus may be rusty or green or tinged with blood.
• Fever.
• Fast breathing and feeling short of breath.
• Shaking and “teeth-chattering” chills. You may have this only one time or many times.
• Chest pain that often feels worse when you cough or breathe in.
• Fast heartbeat.
• Feeling very tired or feeling very weak.
• Nausea and vomiting.
• Diarrhea.

When you have mild symptoms, your doctor may call this “walking pneumonia.”

Older adults may have different, fewer, or milder symptoms. They may not have a fever, or they may have a cough but not bring up mucus. The main sign of pneumonia in older adults may be a change in how well they think. Confusion or delirium is common. Or, if they already have a lung disease, that disease may get worse.

Symptoms caused by viruses are the same as those caused by bacteria. But they may come on slowly and often are not as obvious or as bad.

If you are older than 65, you smoke, or you have a heart or lung problem, you may want to get a pneumococcal vaccine. It may not keep you from getting pneumonia. But if you do get pneumonia, you probably will not be as sick.

You can also lower your chances of getting pneumonia by staying away from people who have the flu, colds, measles, or chicken pox. You may get pneumonia after you have one of these illnesses. Wash your hands often. This helps prevent the spread of viruses and bacteria that may cause pneumonia.

For most people, pneumonia can be treated at home. It often clears up in 2 to 3 weeks. But older adults, babies, and people with other diseases can become very ill and they may need to be in the hospital.

Antibiotics are used to treat pneumonia is caused by bacteria. Pneumonia caused by a virus is treated only with home care, including:

• Get plenty of rest and sleep
• Drink lots of liquids
• Do not smoke
• If your cough keeps you awake at night, talk to your doctor about using cough medicine