The Lung

• The lungs are the organs necessary for exchange of the vital gasses our bodies need. They absorb oxygen from the air we breathe and eliminate carbon dioxide from our blood. This function requires an enormous amount of surface area and so the lung consists of many tiny air sacs and fine passages and in aggregate, most of its volume is merely air. Obviously, this description refers to the healthy organ as the disease processes can radically change this.
  
  

Detection of Consolidation

• Since the healthy lung is mostly air, it very easily transmits sound, vibration and radiation. Auscultation (listening, usually with a stethoscope) provides important information about the state of the organ. Areas filled with fluid, pus, debris or are otherwise damaged sound muted or even silent. Dr. Josef Auenbrugger of Austria (1722-1809), contributed to medical science by noting that by lightly striking the chest wall, the observant doctor could feel vibrations transmitted through healthy lung tissue (or not feel them transmitted, suggesting disease). Later, it was discovered that Roentgen rays (which Professor Roentgen modestly called "X-rays") easily passed through healthy lungs, while being absorbed by and leaving a shadow, when turned to consolidated ones.
  
  

Pathology

• When the lung becomes infected by microbes, they can accumulate in the air passages and aveoli (air sacs). Disease processes can also damage cilia (tiny hairlike structures that move mucus up and out of the respiratory system) causing debris to remain in the lungs. The immune response can contribute to this by sending white blood cells, which can build up in the affected area and inflammation can cause fluid to build up as well.
  
  

Causes

• Pneumonia can be cause by a variety of infectious agents. Various viruses, bacteria and mycoplasms are capable of causing pneumonia in healthy people and can be transmitted via droplets of moisture ejected into the air by coughing or sneezing (which are often symptoms of the disease). Additionally, organisms that are normally extant in our mouth, throat or gut without causing problems, can sometimes be aspirated (breathed in) and cause pneumonia. Even organisms that may be harmless to our lungs can cause pneumonia in a person whose immune system is weakened.
  
  

Treatment

• Because the organisms that cause pneumonia are diverse, treatment must be diverse also. While broad-spectrum antibiotics (chemicals that are effective in killing a wide variety of germs) may be prescribed, most physicians prefer to identify the infectious agent and administer a drug that is most effective to that particular pathogen. Pneumoscystic carnii responds well to sulfa-drugs while fungal infections are treated with amphotericin B, fluconazole or penicillin. Viral pneumonias usually resolve spontaneously, though physicians must watch carefully for secondary infections that might strike while the immune system is busy with the virus.