What Is Pneumonia?

Pneumonia is an inflammation or infection of the lungs most commonly caused by a bacteria or virus. Pneumonia can also be caused by inhaling vomit or other foreign substances.

In all cases, the lungs’ air sacs fill with pus , mucous, and other liquids and cannot function properly. This means oxygen cannot reach the blood and the cells of the body.

Types of pneumonia

Most pneumonias are caused by bacterial infections.

  • The most common infectious cause of pneumonia in the United States is the bacteria Streptococcus pneumoniae.
  • Other bacteria, as well as certain viruses, may also cause pneumonia. Since these infections may not cause all of the classic pneumonia symptoms, they are often called “atypical pneumonias.”
  • Aspiration (or inhalation) pneumonia is a swelling and irritation of the lungs caused by breathing in vomit, fumes from such chemicals as bug sprays, pool cleaners, gasoline, or other substances. This kind of pneumonia cannot be spread to other people.

Nice To Know:

Pneumonia can also be defined by how much of the lung is involved.

  • In lobar pneumonia, one section (lobe) of a lung is affected.
  • In bronchial pneumonia (or bronchopneumonia), patches throughout both lungs are affected.

Facts about Pneumonia:

  • Pneumonia is a serious illness that affects one out of every 100 people each year.
  • Pneumonia can be caused by bacteria or viruses, or by inhalation of vomit or certain chemicals.


What Causes Pneumonia?

There are about 30 different causes of pneumonia. However, they all fall into one of these categories:

  • Infective pneumonia: Inflammation and infection of the lungs and bronchial tubes that occurs when a bacteria (bacterial pneumonia) or virus (viral pneumonia) gets into the lungs and starts to reproduce.
  • Aspiration pneumonia: An inflammation of the lungs and bronchial tubes caused by inhaling vomit, mucous, or other bodily fluids. Aspiration pneumonia can also be caused by inhaling certain chemicals.

Infective Pneumonia

Bacterial pneumonia can attack anyone. The most common cause of bacterial pneumonia in adults is a bacteria called Streptococcus pneumoniae or Pneumococcus. Pneumococcal pneumonia occurs only in the lobar form.

An increasing number of viruses are being identified as the cause of respiratory infection. Half of all pneumonias are believed to be of viral origin. Most viral pneumonias are patchy and the body usually fights them off without help from medications or other treatments.

Pneumococcus can affect more than the lungs. The bacteria can also cause serious infections of the covering of the brain (meningitis), the bloodstream, and other parts of the body.

Nice To Know:

The viruses and bacteria that cause pneumonia are contagious and are usually found in fluid from the mouth or nose of an infected person. Pneumonia can spread by coughs and sneezes, by sharing drinking glasses and eating utensils with an infected person, and contact with used tissues or handkerchiefs.

Handwashing is important when around a person with pneumonia, since the bacteria and viruses can also be spread to your hands and then to your mouth.

Aspiration Pneumonia

Inhaling vomit, irritating fumes, or other substances can result in aspiration pneumonia. Agents such as petroleum solvents, dry cleaning fluid, lighter fluid, kerosene, gasoline, and liquid polishes and waxes are the most likely causes. Pulmonary edema, or fluids in the lung from injury, can develop rapidly. With repeated exposure, the lungs may lose elasticity and small airways may become obstructed. This can lead to increased reactive airway disease and chronic lung disease in adults.

Nice To Know:

Although most cases of pneumonia are caused by a viral or bacterial infection, the disease can also be caused anything that obstructs the bronchial tubes. Tumors, peanuts, hard candies, or small toys in the bronchial tubes can trap bacteria, viruses, or fungi, resulting in pneumonia.

How Is Pneumonia Diagnosed?

A doctor who suspects pneumonia begins by taking a thorough medical history and performing a physical examination. Bacterial pneumonias often come on suddenly; creating a cough that produces mucous that is often colored or “rusty”, fever, and pain along the chest wall.

Infections caused by the Mycoplasma pneumoniae species of bacteria and viruses tend to develop more slowly, after a few days of flu-like symptoms. They can cause a hacky or barky cough, headache, and pain under the breastbone.

The Physical Examination

The most important diagnostic tool for pneumonia may be the stethoscope. In pneumonia, as air passes through mucous and fluids in the lungs, it creates sounds called rales and rhonchi. The doctor will strongly suspect pneumonia if rales are heard on one side of the chest and while the patient is lying down.

The doctor may also tap lightly on the person’s chest, a diagnostic tool called “percussion”. A dull thud instead of a hollow drum-like sound may indicate that the lung has become firm and inelastic from inflammation, called consolidation; or that fluid may be collecting in between the layers of the lung membrane, called pleural effusion.

Several tests may be ordered to help in the diagnosis:

  • Chest x-rays may show signs of infection in the lungs. Different types of pneumonia often will have different patterns on the x-ray.
  • Blood and sputum tests may be performed to collect a specimen if the doctor needs to determine the organism causing the pneumonia.
  • lung biopsy may be performed in severe cases.

Other Diagnostic Procedures

In persons with life-threatening pneumonias more aggressive diagnostic procedures may be required.

  • Thoracentesis is done to remove and analyze fluid from the pleura, the thin membrane that lines the outside of the lung and the chest cavity. Any accumulation of fluid between the layers of the pleura is called a pleural effusion. Fluid in the pleura is withdrawn using a long thin needle inserted between the ribs and analyzed in the laboratory.
  • bronchoscopy may be performed if the physician wants to see inside the lung. In this test, a tube is inserted through the nose or mouth. The tube acts like a telescope into the body, allowing the physician to view the wind-pipe and major airways for pus, abnormal mucous, or other problems.
  • The physician may ask you to breathe into an instrument called a spirometer that measures the amount of air you breathe. This test, called a spirometry, can help to determine how well the lungs are functioning.
  • Some of the bacteria that can cause pneumonia, such as Legionella, Mycoplasma, and Chlamydia, cannot be seen with an ordinary microscope. They are found using special culture techniques or by performing blood tests that detect antibodies to the organisms.
  • Aspiration pneumonias cause changes in the chest x-ray that can be seen six to 24 hours after inhalation. Symptoms include respiratory distress indicated by grunting, cough, and fever after the aspiration of hydrocarbons, foreign substances, or bodily fluids. Symptoms may develop in minutes or hours depending on the volume and nature of the aspirated substance.

How Is Pneumonia Treated?

Treatment depends on the cause and severity of the pneumonia. Antibiotics are used to treat bacterial pneumonia but are ineffective against viral pneumonia.

Treating Infective Pneumonia

Although the treatment for infective pneumonia depends on the cause of the condition, some simple steps can help speed recovery from pneumonia:

  • Medications should be taken exactly as prescribed by a physician. If it is not helping, call the doctor. Do not quit taking it unless told to do so by a doctor.
  • Take over-the-counter medicines such as acetaminophen or ibuprofen to help control pain and fever.
  • Use a cool-mist humidifier or vaporizer to increase air moisture and to make it easier to breathe. DO NOT use hot steam.
  • Rest in bed until body core temperature returns to normal (98.6 degrees F or 37 degrees C) and chest pains and breathing problems are gone. Drink six to eight glasses of liquids daily to help keep mucous thin and easy to cough up.

Treatments For Aspiration Pneumonia

Treatments for aspiration pneumonia focus on breathing support. A breathing tube called an endotracheal tube is usually inserted into the trachea and oxygen is pumped into the lungs.

Suction may be used to clear the airways and to get any remaining chemical or vomit out of the way. Antibiotics are given only if a secondary lung infection develops.

Recovery From Pneumonia

How well a person recovers from pneumonia depends on the type of pneumonia and the person’s general health. Most people with pneumonia recover completely. However, in infants under one year of age, the elderly, and those who are already seriously ill, pneumonia can sometimes be fatal.

How Can Pneumonia Be Prevented?

Some forms of bacterial pneumonia can be prevented with a vaccine (pneumococcal vaccine). The vaccine does not protect against most types of viral pneumonia or the pneumonia that people with low immunity tend to develop.

In most people, vaccination is needed only once in a lifetime. However, others, including those people at highest risk for serious disease, may need to be vaccinated a second time. Individuals should consult their physicians to determine if a second vaccination is recommended.

Those who should get vaccinated include:

  • People over age 65
  • Anyone with a serious chronic illness, such as diabetes or heart disease.

Nice To Know:

Pregnant or nursing women and children under 2 years old should not be vaccinated with the pneumococcal vaccine. Routine revaccination of adults is not recommended.

  • The vaccine for the flu (pneumovax) can help prevent one type of viral pneumonia. Since the flu virus changes from year to year, this shot needs to be given once each year in order to be effective and should also be given to people who are over 65 or who have serious illnesses.
  • Pneumococcal vaccination is appropriate at any time of the year but is most often given at the same time as the influenza vaccine in the early to mid-Fall.

How-To Information:

Personal methods to avoid pneumonia

Prevent pneumonia by taking measures to avoid the organisms that cause respiratory infections, including colds and flu. Always wash hands before eating and after going outside.

Ordinary soap is okay. Expensive antibacterial soaps add little protection, particularly against viruses.

  • Eat a daily diet that includes foods rich in antioxidants, such as fresh, dark-colored fruits and vegetables and other nutrients.
  • Increase lung capacity through brisk walking and other aerobic exercises. Breathing exercises, which train us to take slow, deep, relaxed breaths and exhale through pursed lips, may also be helpful.
  • Do not smoke.

To avoid aspiration pneumonia:

  • Open a window when you use cleaning products, especially when you are in a small room.
  • Do not spray or use chemicals outside when it’s windy. If you must work in the wind, make sure the chemicals are blowing away from you instead of toward you. Wear a mask over your mouth and nose, and wear clothing that protects your skin.
  • Read and follow all safety directions on the labels of any chemical you use.

Are Some People More Likely To Get Pneumonia?

Some groups of people are more susceptible to pneumonia. The elderly, infants, and young children are at highest risk.

  • Elderly people tend to have diminished cough and gag reflexes and weaker immune systems.
  • The immature immune systems and narrow airways of infants and young children make them more likely to develop pneumonia.
  • Another susceptible group consists of people with immune system disorders such as AIDS, or people who are taking medications that lower their immune response. People who have received organ or tissue transplants fall into this category.
  • People who are hospitalized are also at a higher risk for pneumonia. About five to 10 out of every 1000 hospitalized patients contract pneumonia every year.
  • Patients in the intensive care unit on mechanical ventilators are especially susceptible. Their risk of pneumonia can be significantly reduced with antibiotics.
  • Cigarette smoking, or being exposed to cigarette smoke, also increases the risk of pneumonia. Cigarette smoke can injure airways and damage the small hairs that act as filters in the nose and upper airway, called cilia. Toxic fumes, industrial smoke, and other air pollutants may also damage cilia function.

Pneumonia: When Should I Call The Doctor?

You should call your doctor if:

  • You have a high temperature.
  • Your chest pain does not get better in a few days.
  • You are coughing up bloody sputum.
  • You develop a rash, itching, swelling, or stomach pain.

Call your doctor immediately if you begin to have undue difficulty breathing (dyspnea), or your fingernails, toenails, or skin turn dark or bluish (cyanosis). Severe headaches, neck stiffness, or feelings of confusion may be early indications that the infection has spread outside the lungs.

Pneumonia: Frequently Asked Questions

Here are some frequently asked questions related to pneumonia.

Q: Can there be complications from pneumonia?

A: Complications from pneumonia may occur. Secondary infections, which are usually bacterial, may require an additional course of antibiotic treatment, sometimes with a different antibiotic. Rarely, a lung abscess may result from pneumonia. Prompt medical attention can prevent or eliminate most potential complications.

Q: What is “walking pneumonia”?

A: When physicians diagnose someone with walking pneumonia, they are usually talking about an infection with an organism called Mycoplasma pneumoniae. Walking pneumonia is most common between the ages of 5 and 15, and accounts for 70% of pneumonias in children aged 9 to 15. As a rule, mycoplasma pneumoniae infections are not highly contagious. The onset is often so gradual that it may not be noticed at first. A decrease in energy level may be the earliest sign, followed by cold symptoms. The person may complain of a headache, runny nose, and sore throat, and sometimes may have a fever. Unlike a cold, it gradually gets worse over about two weeks, with an increasingly moist cough and possible hoarseness as the disease settles into the chest. Mycoplasma infections are easy to treat, although the antibiotics most commonly prescribed for children are not useful. Mycoplasma is exceptionally sensitive, however, to erythromycin, clarithromycin (Biaxin), azithromycin (Zithromax), and tetracyclines (only used over age 8). These medications are usually effective in five to seven days. Without treatment a person will likely remain sick for a month or more, and may develop complications.

Q: Who pays for the needed vaccinations?

A: Most private insurance plans will pay for both the pneumococcal and flu shots, although you should check with your carrier first. Medicare also pays for both shots in people who are older than 65. People with no medical insurance can take advantage of the many programs that will pay for the vaccines, especially for children. Information about these programs is usually available from your doctor, local hospitals, or county or state health departments.

Q: My father lives in a nursing home. If he gets pneumonia will he have to be moved?

A: If someone living in a nursing home develops pneumonia, they generally can remain in the nursing home to recover. The person usually does not need to be moved as long as his pulse, temperature, and breathing are not significantly abnormal and qualified health care professionals are available to monitor and treat him. If the pneumonia can be treated with oral, injectable, or intravenous antibiotics, hospitalization is not usually necessary.

Q: Who should NOT get the vaccine?

A: Individuals who have had a previous allergic reaction to any component of the pneumococcal vaccine (e.g., hives, difficulty breathing) should avoid vaccination. The vaccine should also be avoided during radiation therapy or chemotherapy. Pregnant women should not be vaccinated unless a doctor, nurse, or midwife advises it. Children less than 2 years old should not get the shot. People who have any immune system deficiencies or who have had an organ transplant should check with their doctors before getting the shot.

Pneumonia: Putting it all together

Here is a summary of the important facts and information related to pneumonia.

  • Pneumonia is an inflammation or infection of the lungs most commonly caused by a bacteria or virus. Pneumonia can also be caused by inhaling vomit or other foreign substances.
  • Pneumonia is a serious illness that affects 1 out of every 100 people in the United States each year.
  • There are two major kinds of pneumonia: infective pneumonia, which is caused by a bacteria or virus, and aspiration pneumonia, which is caused by inhaling vomit, toxic fumes, or other substances.
  • The treatment for pneumonia depends on the cause of the illness.
  • A vaccine that can prevent some types of bacterial pneumonia is widely available. People who get a flu shot each year can avoid some viral pneumonia.
  • The very old and very young, people with compromised immune systems or chronic diseases, and hospitalized patients are at greatest risk for pneumonia.

Pneumonia: Glossary

Here are definitions of medical terms related to pneumonia.

Bronchoscopy: A procedure in which a lighted, tube-like instrument is passed into the large air passageways of the lungs.

Chlamydia: A type of bacteria that causes or is associated with various diseases of the eye, genitals, and urinary tract. It can sometimes cause pneumonia.

Cilia: Delicate hairs that act as filters in the nose and upper airway, using a wave-like motion.

Cyanosis: The blue discoloration of skin, nailbeds, and mucous membranes that indicates low level of oxygen in the blood.

Dyspnea: Difficulty breathing.

Endotracheal Tube: An open-ended tube that is placed within the trachea in order to maintain an open airway and allow assisted breathing.

Lung Biopsy: A test to obtain a specimen of lung tissue for examination. A needle, tube, or surgery is used to take the lung tissue sample.

Meningitis: An inflammation of the membranes that surround the brain. Meningitis is usually used to refer to a bacterial disease that causes the inflammation.

Mycoplasma pneumoniae: A specific kind of bacterium that can cause pneumonia.

Mucous: Sticky phlegm or liquid in the respiratory tract.

Pleura: The thin membranes that line the outside of each lung and the chest cavity.

Pleural effusion: Any accumulation of fluid between the layers of the pleura.

Pleural fluid: The fluid inside the membranes lining the lungs and chest cavity.

Pneumococcal vaccine: A killed or weakened form of the pneumococcus bacteria that is given in order to increase a person’s immunity to the pneumonia-causing bacteria.

Pulmonary Edema: An abnormal accumulation of fluid in the lungs.

Pus: A thick, opaque, and usually yellow-white fluid containing white blood cells, tissue debris, and microorganisms.

Rales (crackles): Clicking, bubbling, or rattling sounds that occur when air moves through fluid-filled airways.

Rhonchi: A coarse gurgling sound in the lungs that indicates the presence of thick fluid.

Spirometry: A test performed by breathing into an instrument called a spirometer, which records the amount and rate of air that is inhaled during a specified time. Some of the test measurements are obtained by normal breathing, and other tests require forced inhalation and/or exhalation.

Streptococcus pneumoniae (pneumococcus): The bacteria that most often cause pneumonia. About 40,000 pneumonia deaths in the United States each year can be traced to Streptococcus pneumonia.

Thoracentesis: Using a long, thin needle inserted between the ribs to remove fluid from the pleura.

Trachea: The main trunk of the hollow tube through which air passes on its way to and from the lungs.

Vaccination: Giving a killed or weakened virus or bacteria in order to stimulate the immune system to protect the person from that organism at next exposure.

Pneumonia: Additional Sources Of Information

Here are some reliable sources that can provide more information on pneumonia.

American Lung Association 
Phone: (800) 586-4872

Offices and website for American Lung Association. The website includes information on pneumonia and other lung-related diseases, including consumer-related information.

National Heart, Lung & Blood Institute Information Center 
Phone: (301) 251-1222

This division of the federal government’s National Institutes of Health deals with lung diseases. Some consumer oriented booklets and pamphlets are available. The site is also a good resource for new treatments being considered.

The American Academy of Family Physicians 
For patient information:

The professional association for family practice doctors throughout the US. It offers a good selection of consumer brochures on many breathing and lung related issues. Many of these are also available on their website.

Canadian Lung Association 
Phone: 613-747-6776

The Canadian Lung Association is the largest group of its kind in Canada. Like the ALA, it has a number of pamphlets and web pages available for consumers and doctors.

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