Pneumonia

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.

Signs and symptoms

People with infectious pneumonia often have a cough producing greenish or yellow sputum, or phlegm and a high fever that may be accompanied by shaking chills. Shortness of breath is also common, as is pleuritic chest pain, a sharp or stabbing pain, either experienced during deep breaths or coughs or worsened by them. People with pneumonia may cough up blood, experience headaches, or develop sweaty and clammy skin. Other possible symptoms are loss of appetite, fatigue, blueness of the skin, nausea, vomiting, mood swings, and joint pains or muscle aches. Less common forms of pneumonia can cause other symptoms; for instance, pneumonia caused by Legionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis or Pneumocystis may cause only weight loss and night sweats. In elderly people, manifestations of pneumonia are seldom typical. They may develop a new or worsening confusion (delirium) or may experience unsteadiness, leading to falls. Infants with pneumonia may have many of the symptoms above, but in many cases they are simply sleepy or have a decreased appetite.

Symptoms of pneumonia need immediate medical evaluation. Physical examination by a health care provider may reveal fever or sometimes low body temperature, an increased respiratory rate, low blood pressure, a high heart rate, or a low oxygen saturation, which is the amount of oxygen in the blood as indicated by either pulse oximetry orblood gas analysis. People who are struggling to breathe, who are confused, or who have cyanosis (blue-tinged skin) require immediate attention.

Findings from physical examination of the lungs may be normal, but often show decreased expansion of the chest on the affected side, bronchial breathing on auscultation with a stethoscope (harsher sounds from the larger airways transmitted through the inflamed and consolidated lung), and rales (or crackles) heard over the affected area during inspiration. Percussion may be dulled over the affected lung, but increased rather than decreased vocal resonance (which distinguishes it from a pleural effusion). While these signs are relevant, they are insufficient to diagnose or rule out a pneumonia; moreover, in studies it has been shown that two doctors can arrive at different findings on the same patient

Posted in: Pneumonia,Respiratory System