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Pneumonia symptoms can vary greatly, depending on any underlying conditions you may have and the type of organism causing the infection. Pneumonia often mimics the flu, beginning with a cough and a fever, so you may not realize you have a more serious condition.

Common signs and symptoms of pneumonia may include:

• Fever
• Cough
• Shortness of breath
• Sweating
• Shaking chills
• Chest pain that fluctuates with breathing (pleurisy)
• Headache
• Muscle pain
• Fatigue

Ironically, people in high-risk groups such as older adults and people with chronic illnesses or weakened immune systems may have fewer or milder symptoms than less vulnerable people do. And instead of having the high fever that often characterizes pneumonia, older adults may even have a lower than normal temperature.

When to see a doctor
Because pneumonia can be life-threatening, see your doctor as soon as possible if you have a persistent cough, shortness of breath, chest pain, unexplained fever — especially a lasting fever of 102 F (38.9 C) or higher with chills and sweating — or if you suddenly feel worse after a cold or the flu.

Be especially prompt about seeking medical care if you're an older adult or you smoke, drink excessively, have an injury, are undergoing chemotherapy or take medication such as prednisone that suppresses your immune system. For some older adults and people with heart failure or lung ailments, pneumonia can quickly become a life-threatening condition.

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Your body has ways to protect your lungs from infection. In fact, you're frequently exposed to bacteria and viruses that can cause pneumonia, but your body normally uses a number of defenses, such as cough and the normal microorganisms (flora) in your body, to prevent harmful organisms from invading and overwhelming your airways. However, numerous conditions, including malnutrition and systemic illness, can lower your protection and allow harmful organisms to get past your body's defenses and into your lungs.

Once the invading organisms are in your lungs, white blood cells — a key part of your immune system — begin to attack them. The accumulating invaders, white blood cells and immune system proteins cause the tiny air sacs in your lungs to become inflamed and filled with fluid, leading to the difficult breathing that characterizes many types of pneumonia.

Classifications of pneumonia
Pneumonia is sometimes classified according to the cause of pneumonia:

• Community-acquired pneumonia. This refers to pneumonia you acquire in the course of your daily life — at school, work or the gym, for instance. The most common cause is the bacterium Streptococcus pneumoniae. Another, less common cause is Mycoplasma pneumoniae, a tiny organism that typically produces milder signs and symptoms than other types of pneumonia. Walking pneumonia, a term used to describe pneumonia that isn't severe enough to require bed rest, may result from Mycoplasma pneumoniae.

• Hospital-acquired (nosocomial) pneumonia. If you're hospitalized, you're at a higher risk of pneumonia, especially if you're breathing with the help of a mechanical ventilator, in an intensive care unit or have a weakened immune system. This type of pneumonia can be extremely serious, especially for older adults, young children and people with chronic obstructive pulmonary diseases (COPD) or HIV/AIDS.

  Hospital-acquired pneumonia develops at least 48 hours after you're admitted to the hospital. This category includes post-operative pneumonia — most common in people older than age 70 who have abdominal or chest surgery — and health-care associated pneumonia — acquired in chronic care facilities, centers where drugs are given by intravenous drip (infusion) and kidney dialysis centers.

  A common predisposing factor for this type of pneumonia is gastroesophageal reflux disease (GERD). This occurs when some of the contents of your stomach flow back into the upper esophagus. From there, the gastroesophageal contents can be inhaled (aspirated) into your windpipe and then into your lower airways. Even small amounts of gastroesophageal reflux can lead to pneumonia in people who are hospitalized.

• Aspiration pneumonia. This type of pneumonia occurs when you aspirate foreign matter into your lungs — most often when the contents of your stomach enter your lungs after you vomit. This commonly happens when a brain injury or other condition affects your normal gag reflex.

  Another cause of aspiration pneumonia is consuming too much alcohol. Aspiration occurs when the inebriated person passes out and then vomits due to the effects of alcohol on the stomach. If someone's unconscious, it's possible to aspirate the liquid contents and possibly solid food from the stomach into the lungs, causing aspiration pneumonia.

  Difficulty swallowing, which occurs with diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease and strokes, may also lead to aspiration pneumonia.

• Pneumonia caused by opportunistic organisms. This type of pneumonia strikes people with weakened immune systems. Organisms that aren't harmful for healthy people can be dangerous for people with AIDS and other conditions that impair the immune system, as well as people who have had an organ transplant. Medications that suppress your immune system, such as corticosteroids or chemotherapy, also can put you at risk of opportunistic pneumonia.
• Other pathogens. Outbreaks of the H5N1 influenza (bird flu) virus and severe acute respiratory syndrome (SARS) have caused serious, sometimes deadly pneumonia infections, even in otherwise healthy people. Although rare, anthrax, plague and tularemia also may cause pneumonia. Some forms of fungi, when inhaled can cause pneumonia. Tuberculosis in the lung also can cause pneumonia.

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Factors associated with an increased risk of pneumonia include:

• Age. If you're age 65 or older, particularly if you have other conditions that make you more prone to developing pneumonia, you're at increased risk of pneumonia. Very young children, whose immune systems aren't fully developed, also are at increased risk of pneumonia.
• Certain diseases. These include immune deficiency diseases such as HIV/AIDS and chronic illnesses such as cardiovascular disease, emphysema and other lung diseases, and diabetes. You're also at increased risk if your immune system has been impaired by chemotherapy or long-term use of immunosuppressant drugs.
• Smoking, alcohol abuse. Millions of microscopic hairs (cilia) cover the surface of the cells lining your bronchial tubes. The hairs beat in a wave-like fashion to clear your airways of normal secretions, but irritants such as tobacco smoke paralyze the cilia, causing secretions to accumulate. If these secretions contain bacteria, they can develop into pneumonia. Alcohol interferes with your normal gag reflex as well as with the action of the white blood cells that fight infection.
• Hospitalization in an intensive care unit. Pneumonia acquired in the hospital tends to be more serious than other types of pneumonia. People who need mechanical ventilation are particularly at risk because the breathing tube bypasses the normal defenses of the upper respiratory tract, prevents coughing, may allow the stomach's contents to back up into the esophagus where they can be inhaled (aspirated), and can harbor bacteria and other harmful organisms.
• Having COPD and using inhaled corticosteroids for more than 24 weeks. Research indicates that this greatly increases your risk of developing pneumonia, possibly serious pneumonia.
• Exposure to certain chemicals or pollutants. Your risk of developing some uncommon types of pneumonia may be increased if you work in agriculture, in construction or around certain industrial chemicals or animals. Exposure to air pollution or toxic fumes can also contribute to lung inflammation, which makes it harder for the lungs to clear themselves.
• Surgery or traumatic injury. People who've had surgery or who are immobilized from a traumatic injury have a higher risk of pneumonia because surgery or serious injuries may make coughing — which helps clear your lungs — more difficult, and lying flat can allow mucus to collect in your lungs, providing a breeding ground for bacteria.
• Ethnicity. If you're a Native Alaskan or from certain Native American tribes, you're at greater risk for contracting pneumonia.

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How serious pneumonia is for you usually depends on your overall health and the type and extent of pneumonia you have.

If you're young and healthy, your pneumonia often can be treated successfully. However, some organisms that cause pneumonia are so virulent that they overwhelm the defense mechanisms, even in otherwise healthy people.

If you have heart failure or lung ailments, especially if you smoke, or if you're older, your pneumonia may be harder to treat successfully. You're also more likely to develop complications, some of which can be life-threatening.

Pneumonia complications may include:

• Bacteria in your bloodstream. Pneumonia can be life-threatening when inflammation from the disease fills the air sacs in your lungs and interferes with your ability to breathe. In some cases the infection may invade your bloodstream (bacteremia). It can then spread quickly to other organs.
• Fluid accumulation and infection around your lungs. Sometimes fluid accumulates between the thin, transparent membrane (pleura) covering your lungs and the membrane that lines the inner surface of your chest wall — a condition known as pleural effusion. Normally, the pleurae are smooth, allowing your lungs to slide easily along your chest wall when you breathe in and out. But when the pleurae around your lungs become inflamed (pleurisy) — often as a result of pneumonia — fluid can accumulate and may become infected (empyema).
• Lung abscess. A cavity containing pus (abscess) that forms within the area affected by pneumonia is another potential complication.
• Acute respiratory distress syndrome (ARDS). The pneumonia involves most areas of both lungs, making breathing difficult and depriving your body of oxygen. Underlying lung disease of any kind, but especially COPD, makes you more susceptible to ARDS.

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You're likely to start by first seeing your family doctor or a primary care provider. However, in some cases when you call to set up an appointment, you may be referred immediately to a doctor who specializes in treating lung disease (pulmonologist) or an infectious diseases doctor, or advised to go to an emergency department.

To get the most information at your appointment, it's a good idea to be well-prepared. Here's some information to help you get ready.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment. Record your temperature.
• Write down key personal information, including recent hospitalizations or exposure to any chemicals or known toxins.
• Make a list of all medications, vitamins and supplements that you're taking.
• Bring a family member or friend along, if possible. It may be difficult to soak up all the information provided to you during an appointment. Someone who goes with you may help you remember.
• Write down questions to ask your doctor.

Preparing a list of questions ahead of time will help you make the most of your time with your doctor. List your questions from most important to least important. For pneumonia, some basic questions to ask your doctor include:

• What is likely causing my symptoms or condition?
• Other than the most likely cause, what are other possible causes?
• What kinds of tests do I need?
• Is my condition likely temporary or chronic?
• What is the best course of action?
• What are the alternatives to the primary approach you're suggesting?
• I have other health conditions. How will my pneumonia affect them?
• Are there any restrictions that I need to follow?
• Should I see a specialist?
• Is there a generic alternative to the medicine you're prescribing?
• Are there any brochures or other printed material that I can take home with me? What Web sites do you recommend?
• If you don't recommend immediate hospitalization for me, how long can we wait before considering hospitalization?

In addition to the questions that you've prepared, don't hesitate to ask questions during your appointment any time that you don't understand or need information clarified.

What to expect from your doctor
Your doctor is likely to ask you a number of questions. It's helpful if you can answer them. Your doctor may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?

What you can do in the meantime
To keep from making your condition worse:

• Don't smoke or be around smoke.
• Don't drink alcohol.
• If you have signs and symptoms of pneumonia, don't go to work or school until your doctor gives you the go-ahead because getting enough rest is important.
• Drink plenty of fluids.
• If you get sicker before you see a doctor, go to an emergency room.

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Your doctor may first suspect pneumonia based on your medical history and a physical exam. You may undergo some or all of these tests:

• Physical exam. During the exam, your doctor listens to your lungs with a stethoscope to check for abnormal bubbling or crackling sounds (rales) and for rumblings (rhonchi) that signal the presence of thick liquid.
• Chest X-rays. X-rays can confirm the presence of pneumonia and determine the extent and location of the infection.
• Blood and mucus tests. You may have a blood test to measure your white cell count and look for the presence of viruses, bacteria or other organisms. Your doctor also may examine a sample of your mucus or your blood to help identify the particular microorganism that's causing your illness.

©1998-2010 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Pneumonia treatments vary, depending on the severity of your symptoms and the type of pneumonia you have.

• Bacterial. Doctors usually treat bacterial pneumonia with antibiotics. Although you may start to feel better shortly after beginning your medication, be sure to complete the entire course of antibiotics. Stopping medication too soon may cause your pneumonia to return. It also helps create strains of bacteria that are resistant to antibiotics.
• Viral. Antibiotics aren't effective against most viral forms of pneumonia. And although a few viral pneumonias may be treated with antiviral medications, the recommended treatment generally is rest and plenty of fluids.
• Mycoplasma. Mycoplasma pneumonias are treated with antibiotics. Even so, recovery may not be immediate. In some cases fatigue may continue long after the infection itself has cleared. Many cases of mycoplasma pneumonia go undiagnosed and untreated. The signs and symptoms mimic those of a bad chest cold, so some people never seek medical attention. The symptoms generally go away on their own.
• Fungal. If your pneumonia is caused by a fungus, you'll likely be treated with antifungal medication.

Dealing with your symptoms
In addition to these treatments, your doctor may recommend over-the-counter medications to reduce fever, treat your aches and pains, and soothe the cough associated with pneumonia. You don't want to suppress your cough completely, though, because coughing helps clear your lungs. If you must use a cough suppressant, use the lowest dose that helps you get some rest.

When hospitalization is needed
If you have severe pneumonia, you'll be hospitalized and treated with intravenous antibiotics and possibly put on oxygen. If you don't need oxygen, you may recover as quickly at home with oral antibiotics as in the hospital, especially if you have access to qualified home health care. Sometimes you may spend three or four days in the hospital receiving intravenous antibiotics and then continue to recover at home with oral medication.

Follow-up treatment
Your doctor will most likely schedule a follow-up X-ray and an office visit after your initial diagnosis and treatment. By that time your infection should have cleared, but it's important for your doctor to see you, even if you're feeling better. Follow-up appointments and X-rays are especially important in smokers.

If you're not feeling better, the follow-up visit is an opportunity for your doctor to determine whether your course of treatment isn't working and order more tests to get more information about your condition.

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If you have pneumonia, the following measures can help you recover more quickly and decrease your risk of complications:

• Get plenty of rest. Even when you start to feel better, be careful not to overdo it.
• Stay home from school or work until after your temperature returns to normal and you stop coughing up mucus. This advice depends partially on how sick you were. If uncertain, ask your doctor. Because pneumonia can recur within a week or so, it may be better not to return to a full workload until you're sure you're well.
• Drink plenty of fluids, especially water. Liquids keep you from becoming dehydrated and help loosen mucus in your lungs.
• Take the entire course of any prescribed medications. Stopping medication too soon can cause your pneumonia to come back and contributes to the development of antibiotic-resistant bacteria.
• Keep all of your follow-up appointments. Even though you feel better, your lungs may still be infected. It's important to have your doctor monitor your progress.

©1998-2010 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The following suggestions can help keep you healthy:

• Get vaccinated. Because pneumonia can be a complication of the flu, getting a yearly flu shot is a good way to prevent viral influenza pneumonia, which can lead to bacterial pneumonia. In addition, even though there is some controversy of its effectiveness, especially in older adults, doctors recommend getting a vaccination against pneumococcal pneumonia at least once after age 50, and if you have any risk factors, every five years thereafter. Your doctor will recommend a pneumonia vaccine even if you're younger than 50 if you're a smoker, if you have a lung or cardiovascular disease, certain types of cancer, diabetes or sickle cell anemia, if your immune system is compromised, or if you've had your spleen removed for any reason.

  A vaccine known as pneumococcal conjugate vaccine can help protect young children against pneumonia. It's recommended for all children younger than age 2 and for children ages 2 to 5 years who are at particular risk of pneumococcal disease, such as those with an immune system deficiency, cancer, cardiovascular disease or sickle cell anemia, or those who attend a group day care center. Side effects of the pneumococcal vaccine are generally minor and include mild soreness or swelling at the injection site.

• Wash your hands. Your hands are in almost constant contact with germs that can cause pneumonia. These germs enter your body when you touch your eyes or rub the inside of your nose. Washing your hands often and thoroughly and can help reduce your risk. When washing isn't possible, use an alcohol-based hand sanitizer, which can be more effective than soap and water in destroying the bacteria and viruses that cause disease. What's more, most hand sanitizers contain ingredients that keep your skin moist. Carry one in your purse or in your pocket.
• Don't smoke. Smoking damages your lungs' natural defenses against respiratory infections.
• Take care of yourself. Proper rest and a diet rich in fruits, vegetables and whole grains along with moderate exercise can help keep your immune system strong.
• Get treatment for GERD. Treat symptomatic GERD, and lose weight if you're overweight.
• Protect others from infection. If you have pneumonia, try to stay away from anyone with a compromised immune system. When that isn't possible, you can help protect others by wearing a face mask and always coughing into a tissue.

©1998-2010 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.