Pneumonia is inflammation of the lungs usually due to infection caused by bacteria, viruses, or other pathogenic organisms. Pneumonia is usually diagnosed by auscultation and chest x-ray. Each year 4,500,000 people become infected with some type of pneumonia. It is the 6th leading cause of deaths due to infectious agents. Prevention includes a pneumococcal vaccine.
There are many types of pneumonia categorized by the causative agent and location of infection. Lobar pneumonia generally effects one lobe. Bronchopneumonia occurs in the smaller lung areas in several lobes. Interstitial pneumonia affects tissues surrounding the alveoli and bronchi. Atypical pneumonia affects the lung tissues rather than the lobe or lobules. Community-acquired pneumonia occurs in non-institutionalized individuals and are usually viral. Nosocomial pneumonia is acquired at a hospital stay. Aspiration pneumonia is caused by inhalation of oropharyngeal microorganisms. Viruses that cause pneumonia are streptococcus pneumophila, Klebsiella pneumonia, Mycoplasma pneumonia, Legionella pneumophila, Chlamydia pneumonia, Moraxella species, or Pneumocystitis carinii. Some immunocompromised individuals are infected by Pneumocystitis jiroveci or fungal infections.
General symptoms are cough, shortness of breath, and fever. With bacterial pneumonia it usually comes on abruptly with a high fever, shaking chills, and pleuritic chest pain. Atypical pneumonia usually has a lower temperature and a nonproductive cough. Treatment varies from hospitalization with oxygen and antibiotics: sometimes pain relievers.
Risk factors include those that are immunocompromised or have underlying chronic medical conditions. Cancer, heart and lung disease, diabetes mellitus, cirrhosis, and renal failure patients have a higher incidence of infections. Smoking, general anesthesia, and endotracheal intubation also increase the risk of infection.