A common serious illness of the lungs

Before antibiotics came into popular use in 1936, pneumonia was called "the Captain of the Men of Death." Today's powerful drugs have significantly reduced the dangers of the condition, but pneumonia is still the most common cause of death due to infectious disease in the United States, and the sixth leading cause overall. There's no doubt about it: Pneumonia should not be taken lightly.

What happens when you get pneumonia? Most often, bacteria overwhelm your body's natural defenses and get into the lungs. The bacteria infect the alveoli, the small air sacs in the lungs that move oxygen from the air to the bloodstream. The tiny air sacs fill with fluid and pus, causing shortness of breath, a productive cough, fever, and other cold-like symptoms.

If you're otherwise generally healthy, contracting pneumonia may require that you stay home sick for a few days to rest your body, take antibiotics, and wait for your symptoms to fade. Your symptoms might linger for a week or longer, and it may take some time to regain all of your strength and energy. You will have to resume your regular activities slowly and comfortably. Even mild pneumonias such as this require a visit to your doctor.

Unfortunately, not all cases of pneumonia are so harmless. People with asthma or other lung conditions who get pneumonia may have difficulty breathing, possibly requiring hospitalization, intravenous antibiotics, and supplemental oxygen. People with diminished immune systems (especially the aged, the chronically ill, and those with serious conditions such as HIV) are often hospitalized early on to prevent pneumonia from becoming life-threatening. Pneumonia can be fatal if enough oxygen cannot reach the body, antibiotics fail, and septic infection spreads throughout the body. (Sepsis is the term that refers to bacteria in the bloodstream.)

If you have a persistent cold or flu, or suspect that you are getting pneumonia (with its symptoms of cough, fever, and chest pain), contact your doctor immediately. Early treatment may hasten your recovery. Carefully following your doctor's instructions and taking extra care of your body are important steps in overcoming pneumonia.

Detailed Description

Pneumonia is not one disease but many diseases. The American Lung Association reports that there are more than 30 different causes of pneumonia, including different kinds of bacteria, fungi, viruses, and even chemicals. Drugs that target the pneumonia-causing germs are the primary treatment for pneumonia.

Bacteria are a common cause of pneumonia, and are treated with antibiotics. Antibiotic treatment is not effective against viruses, which cause about half of all pneumonia, so treatment is more supportive in nature (aimed at easing symptoms and promoting overall health). Less common causes of pneumonia, including fungal and aspiration pneumonia, may also respond to antibiotic treatment. Mycoplasma, responsible for approximately 20% of all cases of pneumonia, can also be treated with antibiotics.

If antibiotics are appropriate, your doctor may, especially if you are already hospitalized, perform tests to determine what bacteria are causing the infection so that drug treatment can be tailored to the infection. Since different causes of pneumonia can cause different patterns of symptoms, doctors often infer the cause of pneumonia and then choose an appropriate antibiotic treatment.

In addition to being classified by infecting organism, pneumonias are often categorized by whether they are acquired in a hospital or through daily life. This "community-acquired" pneumonia is often treated on an outpatient basis, meaning that the person can take medications and stay home. Hospital-acquired (nosocomial) pneumonia accounts for about one-quarter of all pneumonias and occurs when a person contracts pneumonia while in a hospital. It is more serious than community-acquired pneumonia because the person is usually already battling other serious illness and there may be bacteria present that are resistant to some antibiotics.

Here are some of the more common types of pneumonia:

  • Bacterial pneumonia. People of all ages are susceptible to bacterial pneumonia, but debilitated or post-operative people, alcoholics, and people with reduced immunity are most vulnerable. Pneumococcus (Streptococcus pneumoniae) is the organism that causes about 70% of all bacterial pneumonias, and is one type of pneumonia for which there is a vaccine (see Prevention, below). Pneumococcal pneumonia often follows a viral infection such as a cold or flu that has weakened the lungs' defenses, allowing the bacteria to invade them. Pneumococcal pneumonia used to be most commonly treated with the antibiotics penicillin and erythromycin. But today, between 25% and 50% of pneumococcus strains are resistant to them. Amoxicillin with clavulanate, azithromycin, and clarithromycin are favored.
  • Viral pneumonia. Viruses cause about half of all pneumonias. Although most viruses simply cause a cold or flu, others can cause pneumonia, especially in children. Viral pneumonias are common in infants and young children but rare in adults. Antibiotics, which are effective against bacteria but not viruses, are not helpful for this type of pneumonia. Most viral pneumonias are short-lived and go away on their own, but a small percentage can be severe or even fatal. People with decreased immune systems are susceptible to pneumonias caused by cytomegalovirus (CMV) and other herpes viruses, as well as rubeola and adenovirus. Respiratory syncytial virus (RSV) and para-influenza viruses are the most common viral causes of pneumonia in infants and children. Viral pneumonias can also lead to secondary bacterial infections.
  • Mycoplasma pneumonia. Mycoplasma is the tiniest living organism and is the most common cause of pneumonia in people age 5 to 35. It is responsible for up to 50% of adult pneumonias and an even higher percentage of pneumonias in school-age children. Mycoplasma pneumonia (sometimes referred to as "atypical" or "walking" pneumonia) most often occurs in the spring and tends to spread through confined groups, such as students, military personnel, and families. Although it can be severe, mycoplasma pneumonia is usually mild, even when left untreated. However, some people experience long-lasting weakness.
  • Aspiration pneumonia. This less common pneumonia occurs when particles are inhaled into the lungs, causing inflammation or infection. Also known as pyogenic pneumonia, aspiration pneumonia is most common in alcoholics, people with poor dental health, and those with conditions that alter consciousness or decrease normal gag and swallowing reflexes. Aspiration pneumonia can be bacterial, mechanical, or chemical in nature.
  • Other types of pneumonia. Pneumocystis carinii pneumonia (PCP) occurs in about 80% of people with AIDS who do not receive preventive treatment. Caused by an organism thought to be a fungus, PCP can usually be treated successfully with trimethoprim (the generic name for Bactrim), although the infection may return later. Legionnaire's disease accounts for 1% to 8% of all pneumonias and is most common among middle-aged and older people. The organisms that cause the pneumonia (Legionella species) live in water, and outbreaks tend to occur when the organism spreads through the air conditioning systems of hospitals or hotels. Other types of pneumonia include rickettsia and tuberculosis pneumonia.

How Common Is Pneumonia?

Pneumonia is a common serious illness, affecting about 1 out of 100 people (2 million people) each year in the United States. Community-acquired pneumonia is more common in elderly than younger people. In 1997 Ohio researchers estimated that 485,000 Americans annually would need hospitalization for community-acquired pneumonia.

What to Expect

If you're young and otherwise healthy, your strong natural defenses give you a good chance of recovering quickly. The American Lung Association suggests that early antibiotic treatment can cure bacterial pneumonia and speed recovery from atypical pneumonia. Most young, healthy people can be treated at home. Although an effective treatment for viral pneumonia has not been found, it usually resolves on its own.

For bacterial and atypical pneumonia, your doctor usually will choose an antibiotic drug based on the statistically most common organisms that cause pneumonia. Besides antibiotics, your doctor will probably advise you to eat a healthful diet and get plenty of rest. Some patients may also receive medication to ease chest pain and relieve severe coughing. A vigorous young person may resume a normal schedule within a week of recovery from pneumonia. It may take older people weeks to feel well and regain their strength.

The elderly, people with pre-existing breathing difficulties, and people with poor health are often hospitalized and receive intravenous antibiotic treatment to make sure the infection is completely gone. Hospitalized people may also require supplemental oxygen, intravenous fluids, or mechanical breathing assistance. The following groups are most likely to be hospitalized:

  • People age 65 or older
  • People with other serious health problems, such as kidney, heart or lung disease, diabetes, cancer, or a depressed immune system
  • People with low white blood cell count
  • People in whom a severe type of pneumonia is suspected (such as pneumonias caused by Staphylococcus aureus, gram-negative bacilli, or anaerobes)
  • People who cannot take oral medications

Conventional Treatment

Treatment Overview

Mild to moderate cases of pneumonia do not require hospitalization. More severe cases may require a hospital stay so that intravenous antibiotics can be given and the condition can be carefully monitored. If you have a bacterial pneumonia, your doctor will likely prescribe a course of antibiotics to eliminate the pneumonia-causing bacteria. You should also stay at home, get plenty of rest, and drink plenty of fluids.

Since antibiotics do not work against viruses, people with viral pneumonias receive supportive measures. These include increased fluid intake, medications to ease pneumonia symptoms, and supplemental oxygen in severe cases. Hospitalization may be necessary to prevent dehydration in elderly people and young children. Antiviral drugs may be helpful in severe cases or if given at the first sign of symptoms, especially for young children.

Drug Therapy

Antibiotic drugs are the mainstay of treatment for most pneumonia cases. Correctly choosing and using antibiotics is important not only because it more effectively eliminates the infection, but it may also reduce antibiotic resistance. As with all medications but especially with antibiotics, it is crucial that you continue to take the medication as directed by your doctor, even if you start feeling better. This will prevent a more serious infection from returning.

Doctors may perform tests to determine what organism is causing the infection so that drug treatment can be tailored to the infection. However, these tests often take too long or pose unnecessary risk, discomfort, or expense. Fortunately, each organism can cause slightly different symptoms, so your doctor can often determine the cause of your pneumonia based on a physical examination and your medical history. And because of the potentially serious nature of pneumonia, most doctors prescribe antibiotics as soon as possible. Here are some of the antibiotics used to treat certain types of pneumonia:

Bacterial pneumonia


On-Label Efficacy

order Metronidazole

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Off-Label Efficacy

Principen (Ampicillin)

On-Label Efficacy

Ceftin (Cefuroxime)

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Buy Bactrim

On-Label Efficacy


On-Label Efficacy
Viral pneumonia


On-Label Efficacy

Buy Acyclovir

On-Label Efficacy

Ribavirin (aerosol)

On-Label Efficacy


On-Label Efficacy

Interferon alpha

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Mycoplasma and other atypical pneumonias


On-Label Efficacy


On-Label Efficacy


On-Label Efficacy


On-Label Efficacy


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On-Label Efficacy

In addition to antibiotics, your doctor may recommend one or more prescription or nonprescription drugs to ease your pneumonia symptoms. Here are some common choices:

  • Expectorants loosen sputum and may make it easier for you to cough out material from your lungs. Guaifenesin is a popular expectorant.
  • Pain relievers can help symptoms such as headache, chest pain, and sore throat. Over-the-counter products such as acetaminophen (the generic name for Tylenol) and ibuprofen (the generic name for Motrin and Advil) are often used for mild pain relief. Severe pain may require prescription narcotic drugs such as codeine, but these medications may need to be avoided since they suppress the natural cough reflex.

Coughing is your body's natural way of getting rid of unwanted lung fluid, so it's best to allow productive coughs to continue. Sometimes, it is appropriate to suppress the cough (such as at bedtime) so that you can get a good night's rest.


Chest therapy refers to procedures that remove sputum from the lungs and increase lung capacity.

  • An incentive spirometer is a handheld device used to measure a person's breathing ability. The person first completely exhales, then inhales deeply from a breathing tube to cause a gauge in the device to rise as high as possible. It encourages the user to improve his or her ventilation and measure recovery.
  • Rhythmic breathing and coughing exercises bring sputum up and out of the lungs. Every few hours, the person or a caregiver lightly taps on the chest and back to loosen mucus from the lungs. Then, the person inhales three or four times and coughs deeply to produce sputum.

Activity or Diet Modifications

Your doctor will probably recommend plenty of rest. If you have a fever, it is probably best that you stay in bed until it resolves. You can resume your regular activities as long as you can do so comfortably. Avoid strenuous activities until you feel completely better. It may be best to avoid dairy products since they seem to thicken mucus in some people. Dietary modifications include drinking plenty of fluids (3 to 4 quarts daily) and eating nutritious meals.

Monitoring the Condition

Be sure to contact your doctor if:

  • You have shortness of breath
  • You cough up blood
  • You have a temperature greater than 102F
  • Your skin or nail beds become bluish
  • You have severe chest pain
  • You have nausea/vomiting or diarrhea
  • Your symptoms return or don't go away

Possible Complications

  • Pleural effusion
  • Lung abscess
  • Acute respiratory failure
  • Empyema

Quality of Life

A vigorous young person may resume normal activities within a week of recovery from pneumonia. It may take older people weeks to feel well and regain their strength.

Treatment Considerations

Antibiotic resistance. A growing number of pneumonia-causing bacteria, especially pneumococcus, are developing resistance to antibiotics. This can be a serious problem, especially with hospital-acquired pneumonias. Antibiotic resistance occurs when organisms mutate and are able to survive antibiotic exposure. Misuse and overuse of antibiotics worsens the problem. It is crucial that you take your entire course of antibiotics as directed by your doctor, even if you start feeling better before the medication is finished. This will help prevent a more serious infection from returning later on.

Considerations for Children and Adolescents

Young children and infants are more susceptible to certain types of pneumonia and less susceptible to others. In the most severe cases, infants and children are hospitalized to prevent dehydration, to administer intravenous antibiotics, and/or to ensure that their condition is closely and carefully monitored.

Also, cold remedies can harm infants and very young children because their bodies' ability to break down drugs is not fully developed, so be cautious. In particular, be sure to avoid aspirin; the American Academy of Pediatrics warns against giving aspirin to children younger than age 18 to avoid Reye's syndrome, a serious and sometimes fatal condition. Use Tylenol (acetaminophen) or Motrin (ibuprofen) to treat fevers higher than 104F.

Considerations for Older People

Your immune system becomes less effective as you age, which opens the way for viral, bacterial, and other infections, as well as immune disorders and allergies. Older people should contact their doctor if they have a persistent cold, the flu, or bronchitis, since each of these is more likely to lead to pneumonia in older people.

Considerations for Pregnant and Breastfeeding Women

Pregnant women should talk with their doctor before taking any drug (prescription or nonprescription). Drugs may cross the placenta and reach the fetus's bloodstream, possibly affecting normal development. Pregnant women and their doctors must weigh a drug's benefits against its risks to the fetus.


Last updated 22 May 2012


Established Causes

The American Lung Association reports that there are more than 30 different causes of pneumonia. These include several types of bacteria, viruses, fungi, mycoplasma, and chemicals. Particles of these substances are breathed into the lungs from the air (or more rarely the stomach). Normally, the upper portion of the respiratory tract efficiently removes germs before they can settle in the lungs. Pneumonia occurs when this defense system is compromised and/or overwhelmed by too many germs. For instance, when your body mounts a response to a cold or flu virus, it has fewer germ-fighting cells available to fend off pneumonia-causing organisms. Alcohol, narcotics, nervous system diseases, and physical obstructions can also decrease the upper respiratory system's ability to protect the lungs from infectious organisms.

Risk Factors

The following risk factors may make you more likely to get pneumonia than others:

  • Age 65 or older
  • Age 2 or younger
  • Depressed immune system (such as people with HIV, those undergoing cancer treatment, and organ transplant recipients)
  • Alcoholism
  • Cigarette smoking
  • Diabetes
  • Heart failure
  • Chronic obstructive pulmonary disease (COPD)
  • Recent abdominal surgery
  • Recent chest injury

Symptoms & Diagnosis

Symptoms of Pneumonia

Pneumonia symptoms may come two or three days after signs of a common cold or flu (sore throat, a stuffy or runny nose, or a mild cough). The symptoms of pneumonia vary depending on the organism causing the infection, and the intensity of pneumonia symptoms may also vary from person to person. Most pneumonias share some of the following traits:

  • Cough producing phlegm
  • Chills with shaking
  • Chest pain
  • Fever
  • Shortness of breath

Less common and more variable symptoms of pneumonia may include the following:

  • Rapid or difficult breathing
  • Fatigue
  • Headache
  • Loss of appetite
  • Nausea and/or vomiting
  • Abdominal pain
  • Crackling sounds during breathing

Conditions That May Be Mistaken for Pneumonia

  • Chronic bronchitis
  • Tuberculosis
  • Bronchiectasis
  • Asthmatic bronchitis
  • Pulmonary edema
  • Respiratory distress syndrome
  • Interstitial lung disorders
  • Lung cancer

How Pneumonia Is Diagnosed

Doctors can often diagnose and treat mild to moderate cases of community-acquired pneumonia based on your medical history, a physical examination, and likely a chest X-ray. Hospital-acquired pneumonia can be more difficult to diagnose because the person may have other serious conditions with pneumonia-like symptoms.

Your doctor will first ask about your symptoms. He or she may want to know if you've been exposed to anyone with pneumonia, if you recently had a respiratory illness, and if you smoke or drink. Your doctor will use a stethoscope to listen for changes in your breathing sounds characteristic of pneumonia. Crackling or rumbling sounds point toward pneumonia, especially if they are heard on one side of the chest while you are lying down. If your doctor is uncertain about your condition, several tests can help confirm whether or not you have pneumonia.


Chest X-rays are very helpful in confirming findings of pneumonia. Pneumonia appears on the X-ray film as whitish areas called infiltrates. Although of limited use in determining the organism causing the infection, chest X-rays can effectively help doctors determine the extent and location of infection. In addition, X-rays can detect complications of pneumonia, such as abscesses and fluid around the lungs (pleural effusion).

If your chest X-ray is unclear, then a computed tomography (CT or CAT) or MRI scan may be used. These more precise, costlier tests also may be helpful for people who do not respond to treatment or have other serious medical conditions, including HIV/AIDS. CT and MRI scans can also detect tissue damage, enlarged lymph nodes, and any tumors or other objects blocking the airways to the lungs.

Specific Tests

  • Sputum tests. Sputum is the material coughed up from the lungs and brought up through the mouth. The color, amount, consistency, and odor of the sputum can indicate what type of pneumonia is present. To perform a sputum gram stain test, your doctor will ask you to cough as deeply as possible into a specimen container. The sample is sent to a laboratory, where it is either examined under the microscope or cultured to see what organisms flourish.

    If a bacterial pneumonia is suspected, a sputum gram stain is particularly helpful in determining the pneumonia-causing bacteria. Sputum samples are placed on a thin slide and stained with a violet dye called a gram dye to reveal the presence of bacteria. Bacteria are often categorized as either gram-positive or gram-negative, based on whether they absorb the dye or not. Gram-positive bacteria include pneumococcus, Staphylococcus aureus, group B streptococcus, and group A streptococcus. Gram-negative bacteria include species of pseudomonas, haemophilus, and moraxella, as well as Haemophilus influenza type B. Special stains are necessary to reveal fungal infections.

  • Bronchoscopy. This procedure may be used in people with serious pneumonia when other methods are not available. A small, flexible tube is inserted into one nostril down the respiratory tract to obtain samples from the lower regions closer to the lungs.
  • Lung needle biopsy. A needle is inserted into the chest with the guidance of X-rays or CT scans to obtain a sample of the lung area. This procedure is usually reserved for people with serious pneumonia when other methods for determining the pneumonia-causing organism do not work.

Laboratory Work

  • Complete blood count (CBC). This blood test measures the amounts of different types of blood cells in the bloodstream. Most people with bacterial pneumonia have an elevated white blood cell count.
  • Arterial blood gas test. This procedure is used in severe cases of pneumonia interfering with the lung's ability to oxygenate the blood. It measures how much carbon dioxide is in the bloodstream. The procedure requires blood to be drawn from the artery, which may be more uncomfortable than drawing it from a vein.
  • Other blood tests. Some pneumonia-causing organisms cannot be seen with a microscope, including the bacterium Legionella and the bacteria-like organisms Chlamydia and Mycoplasma. Special blood tests must be performed that detect antibodies to these organisms.

Alternative care

Little is known about the safety and effectiveness of alternative treatments for lung diseases such as chronic bronchitis, asthma, and pneumonia. A 1991 Dutch study suggested that these treatments may represent an unnecessary expense. Because of the potential serious consequences of improper treatment, your doctor may recommend that you not rely on these less-proven therapies.


  • Zinc may strengthen the immune system, making it more capable of fighting off infections. Researchers at Johns Hopkins University and at the World Health Organization examined 10 studies and concluded that zinc supplementation reduces the risk of pneumonia in children and infants by 41%. Zinc deficiency is more common among children in developing countries and children with malnutritional diets.
  • N-Acetylcysteine (NAC) has been shown to help pulmonary diseases by increasing sputum volume and making it easier to cough up. However, NAC may irritate the airway lining and is not recommended for people with asthma.
  • Vitamin C plays an important role in the immune system by stimulating the production of interferon, a natural virus-killer. Although supplementing with vitamin C is an increasingly popular way to beat back the common cold, its usefulness in pneumonia is unknown.

Self care & Prevention


  • Get a pneumococcal vaccine. This vaccine can protect up to 70% of people from infection with Streptococcus pneumoniae, the most common cause of bacterial pneumonia. Many clinicians recommend the vaccine to people in high-risk groups, including elderly people and people with heart or lung conditions and diabetes. The World Health Organization states that the vaccine may most benefit healthy elderly people; unfortunately, its effectiveness is questionable in children younger than 2 years of age and people with HIV.
  • Get a flu shot. Avoiding the flu (influenza) will help prevent secondary pneumonia. The flu shot prevents the flu in up to 90% of people who receive it.
  • Practice good hygiene. Wash your hands frequently, especially before eating and after going outside. Pneumonia-causing viruses and bacteria are contagious. They are found in the mouths and noses of infected people and can be spread by coughs and sneezes, contaminated drinking glasses and eating utensils, and dirty tissues or handkerchiefs.
  • Breastfeed your baby. Breastfeeding boosts infants' immunity against certain pneumonia-causing viruses.
  • Exercise. Even moderate exercise increases lung capacity and boosts the immune system. Try taking a brisk walk every day.
  • Avoid the common cold. In addition to exercise, eat plenty of fresh, dark-colored fruits and vegetables. They are rich in antioxidants and other nutrients that can boost your immunity.

Self-Care Measures

  • Get plenty of rest. Stay in bed until your fever passes and you can breathe easily. Refrain from strenuous activities until your body is 100% again.
  • Drink plenty of fluids. This will help thin lung fluids and make it easier to cough up sputum. Warm fluids might also ease throat pain and nasal dryness.
  • Try breathing exercises. Breathe deeply three or four times, then cough as much sputum up as possible. You can also tap on your chest or back to help loosen mucus from the chest walls, making it easier to expel. Ask your doctor for instructions.
  • Ask your doctor before using cough medicine. Cough-suppressant medicines may be appropriate at bedtime to help you rest, but they also hamper your body's natural instinct to remove excessive lung fluids.
  • Use over-the-counter drugs for minor pain. Good choices include aspirin and ibuprofen. Feverish people age 21 or younger should not take aspirin products in order to avoid Reyes' syndrome, a serious potential complication.
  • Use a heating pad. On low settings, heating pads may help ease chest and body pains.