SPECIAL ISSUE ON COMMUNITY ACQUIRED PNEUMONIA • JANUARY 2012 • VOL. 60

Epidemiology of Community Acquired Pneumonia

Alaka Deshpande

Professor, Dept. of Medicine, Grant Medical College & Sir JJ Group of Hospitals, Byculla, Mumbai 400 008.

Pneumon is a Greek word for lungs. Pneumonia is a disease of the lungs. Pneumonia is a common cause of infection related mortality and is one of the most important challenges in clinical medicine. In US alone, 4 million adults are affected each year of which 20% need hospitalization for the management. It is common at both extremes of age and during winter months. In India, rise in pneumonia cases is also noted during monsoon.

Independent risk factors for CAP are alcoholism, tobacco smoking COPD. The rate of pneumococcal pneumonia is upto 40 times higher among HIV infected patients than among age matched patients not infected with HIV. Dementia, cerebrovascular accident, seizures are other risk factor so also diabetes mellitus.

Pneumon is defined as an inflammation of the alveoli, distal airways and interstitium of the lungs. The alveoli are filled with inflammatory exudates with white blood cells, red blood cells and fibrin. Pathologically it is characterized by consolidation. Clinically it is a constellation of symptoms and sings.

Pneumonia which develops outside the hospital is considered as community acquired pneumonia. Pneumonia developing 72 hrs or more after hospitalization is Nosocomial or Hospital Acquired.

Epidemiologically it can be classified as

1. Community acquired pneumonia CAP
2. Nosocomial or Hospital Acquired Pneumonia HAP
3. Ventilator Associated Pneumonia VAP
4. Aspiration Pneumonia.
5. Pneumonia in immune compromised hosts.

The pneumonia can be caused by

The mortality for non-hospitalized patients is 1% while it rises to more than 30% in hospitalized cases particularly in patients admitted to intensive care unit.

With the globalization, there is increased international travel. Due to worldwide unrest, there is lot of migration. Therefore while managing a case of pneumonia these factors have to be taken in to consideration