Pneumonia Causes, Symptoms, Signs and Treatment (Viral, Bacterial) on MedicineNet.com

Font Size

Pneumonia

Bronchitis Slideshow

The Common Cold Slideshow

Medical Author (Revision): George Schiffman, MD
Medical Editor (Revision): Melissa Conrad Stöppler, MD

Pneumonia Vaccine Information

The Primary Causes of Death from Pneumococcus are Pneumonia

Pneumonia's a contagious lung infection caused by bacteria, viruses, or fungi and can be prevented with a vaccine.

Streptococcus pneumoniae are bacteria frequently found in the upper respiratory tract of healthy children and adults. These bacteria, however, can also cause a range of infections�from relatively mild ear infections to fatal pneumonia, meningitis, and sepsis. Serious pneumococcal infections can occur throughout life, but children under 2 years old and the elderly are at highest risk.

Serious pneumococcal infections are a major global health problem. The World Health Organization (WHO) estimates that more than 1.6 million people�including more than 800,000 children under 5 years old�die every year from pneumococcal infections. Nearly all these deaths occur in the world's poorest countries. Pneumococcal meningitis is the most severe form of pneumococcal disease and one of the most fatal childhood illnesses. In developing countries, it kills or disables 40 to 70 percent of children who get it.

The primary causes of death from pneumococcus are pneumonia, in which fluid fills the lungs, hindering oxygen from reaching the bloodstream; meningitis, an infection of the fluid surrounding the spinal cord and brain; and sepsis, an overwhelming infection of the bloodstream by toxin-producing bacteria.

Learn more about the pneumonia vaccine »

SOURCE: National Institute of Allergy and Infectious Diseases; "Pneumococcal Disease."

What is pneumonia?

Pneumonia is an infection of one or both lungs which is usually caused by bacteria, viruses, or fungi. Prior to the discovery of antibiotics, one-third of all people who developed pneumonia subsequently died from the infection. Currently, over 3 million people develop pneumonia each year in the United States. Over a half a million of these people are admitted to a hospital for treatment. Although most of these people recover, approximately 5% will die from pneumonia. Pneumonia is the sixth leading cause of death in the United States.

How do people "catch pneumonia"?

Some cases of pneumonia are contracted by breathing in small droplets that contain the organisms that can cause pneumonia. These droplets get into the air when a person infected with these germs coughs or sneezes. In other cases, pneumonia is caused when bacteria or viruses that are normally present in the mouth, throat, or nose inadvertently enter the lung. During sleep, it is quite common for people to aspirate secretions from the mouth, throat, or nose. Normally, the body's reflex response (coughing back up the secretions) and immune system will prevent the aspirated organisms from causing pneumonia. However, if a person is in a weakened condition from another illness, a severe pneumonia can develop. People with recent viral infections, lung disease, heart disease, and swallowing problems, as well as alcoholics, drug users, and those who have suffered a stroke or seizure are at higher risk for developing pneumonia than the general population.

Once organisms enter the lungs, they usually settle in the air sacs of the lung where they rapidly grow in number. This area of the lung then becomes filled with fluid and pus as the body attempts to fight off the infection.

What are pneumonia symptoms and signs?

Most people who develop pneumonia initially have symptoms of a cold which are then followed by a high fever (sometimes as high as 104 degrees Fahrenheit), shaking chills, and a cough with sputum production. The sputum is usually discolored and sometimes bloody. People with pneumonia may become short of breath. The only pain fibers in the lung are on the surface of the lung, in the area known as the pleura. Chest pain may develop if the outer pleural aspects of the lung are involved. This pain is usually sharp and worsens when taking a deep breath, known as pleuritic pain.

In other cases of pneumonia, there can be a slow onset of symptoms. A worsening cough, headaches, and muscle aches may be the only symptoms. In some people with pneumonia, coughing is not a major symptom because the infection is located in areas of the lung away from the larger airways. At times, the individual's skin color may change and become dusky or purplish (a condition known as "cyanosis") due to their blood being poorly oxygenated.

Children and babies who develop pneumonia often do not have any specific signs of a chest infection but develop a fever, appear quite ill, and can become lethargic. Elderly people may also have few symptoms with pneumonia.