Community acquired pneumonia spreads when an individual inhales droplets of sneeze or cough from an infected person. Hence it is easily transmitted by close person to person contact. Several different organisms including bacteria, viruses and fungi are responsible for causing CAP. The most common organism causing CAP is a bacterium known as Streptococcus pneumonia. Although many organisms or "bugs" have been confirmed as causing CAP, around 30% to 50% of pneumonia cases are believed to have an unknown cause. This means that the actual "bug" responsible for causing the disease has not been identified or isolated even after laboratory testing.
Streptococcus pneumonia(pneomococcus) and other bacterial pneumonias are usually the most serious and constitute the most common cause of CAP especially in adults. In young children, especially those between 2 and 3, respiratory viruses are the most common causes of pneumonia. As the school going age approaches, Mycoplasma pneumonia becomes more common.
In case of the elderly or those who are debilitated, it has been observed that bacterial pneumonia may follow influenza or even the common cold. Pneumonia can even be contracted by people admitted to hospitals for other ailments. This often proves to be more dangerous as the patient's immune system has already suffered a setback from the original ailment. There is also the risk of catching an infection from bacteria are resistant to antibiotics.
Risk factors comprise of typical characteristics that increase the probability of developing a condition. The more the risk factors prevailing, the higher are the chances of catching the infection. You would be at increased risk of developing CAP if one or more of the following factors apply to you:
- Are over 65 years of age
- Have other medical conditions or a combination of conditions like:
- Chronic obstructive lung disease (COPD) or other chronic lung ailments
- diabetes mellitus
- chronic kidney disease
- heart failure
- coronary artery disease
- chronic liver disease
- cystic fibrosis
- Are a smoker
- Have been habitually exposed to chemicals and pollutants used in agriculture, industries or construction. Prolonged exposure to these pollutants could damage the lungs, leading to lung infection and rendering the lungs more vulnerable to infection.
- Are an alcoholic
- Have a weakened immune system.