Pneumonia is not a specific disease. It is a general term for several kinds of inflammation of the lungs. Pneumonia is usually caused by a bacterial or viral infection, but it can also be caused by chemical damage to the lungs from inhaling a poisonous gas such as chlorine. The pneumonia, or lung infection, can be anything from a mild complication of an upper respiratory tract infection to a life- threatening illness.
The symptoms, the treatment, the impact, and the outcome of pneumonia depend on the cause, the general health of the person concerned, and on other factors. Viral pneumonia, for instance, does not respond to treatment with antibiotics. See the accompanying table for a comparison of the causes and likely results of five of the most common types of pneumonia.
The variability of pneumonia has led to many popular and medical descriptive terms. If you are told that you have "double" pneumonia, it means that both your lungs are affected. If your attack is due to bacteria-like microbes called Mycoplasma, you may have said to have "atypical" pneumonia. "Bronchopneumonia" is patchy inflammation of one or both lungs, and "lobar" pneumonia affects the entire area of one or more lobes of the lung. When your physician determinates what kind of pneumonia you have, you can ask for a description of that type.
What are the symptoms?
No single symptom is characteristic of all types of pneumonia. You should consider the possibility of pneumonia, however, if you already have a respiratory illness with symptoms such as a cough and fever, and you become short of breath while at rest and for no apparent reason. Additional symptoms to watch for coupled coughing and a temperature are chills; sweating; chest pains; cyanosis, or a bluish tinge to the skin; blood in the phlegm; and, occasionally, mental confusion or delirium. The larger the lung area that is affected, the more severe the symptoms you experience will be.
How quickly the symptoms begin and which symptoms are most prominent varies with the cause of the infection. An especially virulent strain of the influenza virus can cause a pneumonia that can kill a feeble person within 24 hours. In a healthy young adult, pneumonia resulting from a mild respiratory infection may cause symptoms that are no worse than those of an ordinary cold.
What are the risks?
In the United States, about 15 people out of 1,000 have pneumonia each year. The disorder is often the final complication of some other debilitating disorder, and this is why many people who get pneumonia die. Any one whose resistance is already low is very susceptible to pneumonia, so for people who are dying of heart failure, cancer, stroke or chronic bronchitis, the actual cause of death is often pneumonia. In anyone who is semiconscious or paralyzed, infection of the lungs is extremely likely. This is due under such conditions the normal coughing reflex that keeps the lungs clear of mucus and stagnant fluid is reduced, or even absent.
You are also more likely than other people to get pneumonia if you are very young (under 2) or very old (over 75), if you have a chronic chest disease such as asthma or some other chronic illness that reduces your body's resistance to infections , or if you are a heavy smoker or drinker. If you are under longterm treatment with immune or anti-inflammatory drugs, especially steroids, you are also susceptible to pneumonia. These drugs decrease the body's normal defenses against infection.
Because pneumonia varies so much, no generalizations can be made about its outcome. In old, weak, or debilitated people, the main risk is death. Any type of pneumonia may lead to pleurisy, or empyema. The most dangerous type of pneumonia is caused by viruses such as an influenza virus, because they do not respond to antibiotics. Compare the mortality rate for viral pneumonia in the accompanying table with that for a form of pneumonia caused by pneumococcus bacteria, which is simply virulent but can be treated with antibiotic drugs. With increasing age or chronic illness, your chances of surviving even a mild case of pneumonia are reduced more and more with time.
What should be done?
Even if you have some of the symptoms usually associated with pneumonia, do not assume that you have it. Assume instead that you have a cold or some other infection of the respiratory tract, and take care of yourself accordingly. Consult your physician at once, however, if you become short of breath even when lying down, if your chest hurts when you breathe, or if you cough up blood stained sputum. Your physician will probably listen to your chest through a stethoscope, percuss, or finger tap, your chest, and ask you questions about the onset of symptoms and your smoking and drinking habits. It may be possible to make a firm diagnosis of pneumonia, and even of the type of pneumonia, based on such an examination. However, further tests such as a chest X-ray and laboratory examination of both blood and phlegm samples may also prove to be necessary.
What is the treatment?
Self-help: None is possible.
Professional help: Because pneumonia can unexpectedly become sever in a matter of hours, your physician may recommend hospitalization. The best treatment may be simply a combination of warmth, soothing cough medicines, and antibiotics. However, close professional supervision and observation are extremely desirable during the early stages of pneumonia, especially if there is some doubt about the precise nature and extent of the inflammation.
Antibiotic drugs may be given orally or by injection. There is a wide variety of antibiotics, and the choice for your case will depend heavily on the probable cause of your illness. Laboratory tests of your blood and sputum should indicate what is causing your infection. Your doctor will also need to find out if there are any antibiotics to which you are either allergic or particularly responsive.
Analgesics such as aspirin help to tie chest pain. If you are very breathless and turning blue, you are probably in need of oxygen, which is generally supplied with a face mask or a tube in your nose. If your lungs remain troublesome in spite of all attempts at treatment, your physician may recommend further tests. For example, bronchoscopy may be done to exclude the possibility of lung cancer.
A healthy young person should recover completely within two to three weeks. Even in cases of viral pneumonia, the chances of serious complications are minimal, since antibiotics can prevent secondary bacterial infection. Following recovery, you may still feel very tired for a long time after the infection is gone. A heavy cigarette smoker, or someone who is vulnerable in some other way, may take several months to recover from the illness or may die.