Diseases of the Respiratory System - Pneumonia

Pneumonia might be defined as any inflammation of the lung tissue itself, but the term is generally applied only to infections of an acute or rapidly developing nature caused by certain bacteria or viruses. The term is generally not used for tuberculous or fungal infections. The most common severe pneumonia is that caused by the pneumococcus bacterium .

Pneumonia develops from inhaling infected mucus into the lower respiratory passages. The pneumococcus is often present in the nasal or throat secretions of healthy people, and it tends to be present even more often in the same secretions of an individual with a cold. Under certain conditions these secretions may be aspirated , or inhaled, into the lung. There the bacteria rapidly multiply and spread within hours to infect a sizable area. As with the common cold, chilling and fatigue often play a role in making this sequence possible. Any chronic debilitating illness also makes one very susceptible to pneumonia.


Pneumonia develops very suddenly with the onset of high fever, shaking chills, chest pain, and a very definite feeling of total sickness or malaise. Within hours enough pus is produced within the lung for the patient to start coughing up thick yellow or greenish sputum that often may be tinged or streaked with blood. The patient has no problem in recognizing that he has suddenly become extremely ill.

Prior to penicillin the illness tended to last about seven days, at which time it would often suddenly resolve almost as quickly as it started, leaving a healthy but exhausted patient. But it also could frequently lead to death or to serious complications, such as abscess formation within the chest wall, meningitis, or abscess of the brain. Because penicillin is so very effective in curing this illness today, physicians rarely see those complications.


The response of pneumococcal pneumonia to penicillin is at times one of the most dramatic therapeutic events in medicine. After only several hours of illness the patient presents himself to the hospital with a fever of 104° F, feeling so miserable that he does not want to eat, talk, or do anything but lie still in bed. Within four to six hours after being given penicillin he may have lost his fever and be sitting up in bed eating a meal. Not everyone responds this dramatically, but when someone does, it is striking.


There is no guaranteed way to prevent pneumonia. The advice to avoid chilling temperatures, overexertion, and fatigue when one has a cold is directed principally toward avoiding pneumonia. Anybody exposed to the elements, especially when fatigued and wearing damp clothing, is particularly susceptible to pneumonia; this explains its frequent occurrence among army recruits and combat troops. The elderly and debilitated become more susceptible when exposed to extremes of temperature and dampness.

Pneumonia is not really a contagious illness except in very special circumstances, so that isolation of patients is not necessary. In fact, all of us carry the pneumococcus in our noses and throats, but we rarely have the constellation of circumstances that lead to infection. It is the added physical insults that allow pneumonia to take hold.

Other Kinds of Pneumonia

All bacteria are capable of causing pneumonia and they do so in the same manner, via the inhalation of infected upper airway secretions. Some diseases, such as alcoholism, tend to predispose to certain bacterial pneumonias. Usually these are not as dramatic as those caused by the pneumococcus, but they may be much more difficult to treat and thereby can often be more serious.

Far less severe are the pneumonias caused by certain viruses or a recently discovered organism that seems to be intermediate between a virus and a bacterium. The term walking pneumonia is often applied to this type, because the patient is often so little incapacitated that he is walking about and not in bed. These pneumonias apparently occur in the same way as the bacterial pneumonias, but the difference is that the infecting agent is not capable of producing such severe destruction. These pneumonias are usually associated with only mild temperature elevation, scant amount of sputum production, and fewer general body symptoms. They should be suspected when coughing dominates the symptoms of a cold, especially if it turns from a dry or nonproductive cough to one that produces sputum. Antibiotic therapy tends to hasten recovery and prevent the complication of bacterial pneumonia.


No discussion of pneumonia is complete without mention of pleurisy . This term refers to any inflammation of the lining between the chest wall and the lung. Infection is only one of the causes, but probably the most common, of inflammation of the pleura . Pleurisy is almost always painful, the pain being felt on inhaling and exhaling but not when the breath is quietly held for a brief period. It is a symptom that always deserves the attention of a physician and investigation of its cause. The same type of pain on breathing can often be mimicked by a strain of the chest wall muscles, but the difference can usually be determined by a physician's examination. If not, a chest X ray will help to reveal the cause of the pain.

User Contributions:

Comment about this article, ask questions, or add new information about this topic: