Although early treatment is the best way to recover fully and quickly, pneumonia is challenging to diagnose. It sometimes seems like a simple cold or the flu, and its signs can vary depending on what is causing the pneumonia. Symptoms include:
- A persistent cough
- An unexplained fever, especially one of 102° F or higher for several days in a row
- Chest pain that changes with breathing
- Chills and sweats
- Shortness of breath
- Suddenly feeling worse after a cold or influenza
Anyone with these symptoms should not hesitate to call a doctor. People who should be especially concerned with these symptoms include older adults and individuals who are undergoing chemotherapy, have a suppressed immune system, are taking drugs that suppress the immune system (e.g., prednisone), are affected by alcoholism, have been injured, are confined to bed or have heart conditions or other conditions that affect the ability to breathe.
Pneumonia can turn fatal within 24 hours under certain conditions. Seeking early treatment is important to ensure that the condition does not become life threatening.
Some complications that can occur with pneumonia are:
- The lungs may swell because the disease can fill up the air spaces inside the lungs, making breathing difficult.
- The infection that causes the pneumonia can spread into the bloodstream and then to other organs.
- Fluid can collect between the lining (pleurae) of the lungs and the lining of the inside of the chest. When fluid collects inside it is called pleural effusion. This fluid can become infected (a condition known as empyema) and may need to be drained through a tube inserted between the ribs.
Causes and Risk Factors
Some of the organisms that cause pneumonia are commonly found in the air. The lung's natural defenses normally protect against infection from these organisms, but they sometimes break through these defenses.
Pneumonia may be caused by:
Bacteria. The most common cause of pneumonia is bacterial infection, and many different bacteria can cause the condition, producing mild to severe cases. Bacterial pneumonia can occur independently or following illnesses, such as colds, flu or upper respiratory infections.
Fungi. Certain types of fungus can cause pneumonia. When the fungus is inhaled, some people develop symptoms of acute pneumonia, others develop a form that lasts for months, although most people experience few if any symptoms. Pneumocystis carinii, a yeast-like fungi that is known as an opportunistic infection because it usually affects individuals with compromised immune systems, such as those with AIDS or undergoing chemotherapy.
Viruses. Several different viruses can cause pneumonia, including some of the same viruses that cause influenza. This type of pneumonia usually hits in the fall and winter and is more serious in people with heart or lung disease. People who have viral pneumonia can also develop bacterial pneumonia.
Other microorganisms. In rare cases, other living organisms may be responsible for pneumonia. These organisms include amoebas and mycoplasmas (which have characteristics of both bacteria and virus).
Other foreign materials. Pneumonia can occur when food, mucus, vomit, chemicals or other substances enter the lungs. Called aspiration pneumonia, this condition can develop from accidentally inhaling substances during a seizure, unconsciousness or stroke.
Persons who are at greater risk of developing pneumonia include those who:
- Abuse alcohol (Alcohol interferes with the action of the white blood cells, which fight infections.)
- Abuse drugs (Injection of illegal drugs can put you at greater risk of getting infections that can affect your lungs.)
- Are age 65 or older
- Are smokers (smoke damages the air passages inside the lungs)
- Are very young children (whose immune systems are not fully developed)
- Have an impaired immune system due to chemotherapy, immunosuppressant drugs or illness
- Have been exposed to certain chemicals or pollutants
- Have certain diseases, such as HIV/AIDS, heart disease, emphysema or diabetes
- Have had the spleen removed
- Live in areas where exposure to types of fungus is greater (An example is valley fever, which is widespread throughout Southern California and the desert of the Southwest. This fungus does not affect everyone who is exposed to it, but a few develop severe pneumonia.)