Bacterial pneumonia, which is the most common form, tends to be more serious than other types of pneumonia, with symptoms that require medical care. The symptoms of bacterial pneumonia can develop gradually or suddenly. Fever may rise as high as a dangerous 105 degrees F, with profuse sweating and rapidly increased breathing and pulse rate. Lips and nailbeds may have a bluish color due to lack of oxygen in the blood. A patient's mental state may be confused or delirious.

The symptoms of viral pneumonia usually develop over a period of several days. Early symptoms are similar to influenza symptoms: fever, a dry cough, headache, muscle pain, and weakness. Within a day or two, the symptoms typically get worse, with increasing cough, shortness of breath and muscle pain. There may be a high fever and there may be blueness of the lips.

Symptoms may vary in certain populations. Newborns and infants may not show any signs of the infection. Or, they may vomit, have a fever and cough, or appear restless, sick, or tired and without energy. Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower than normal temperature. Older adults who have pneumonia sometimes have sudden changes in mental awareness. For individuals that already have a chronic lung disease, those symptoms may worsen.

When to call a doctor

If you think you or your child has symptoms of pneumonia, don't wait for the disease to get even worse before you seek care. Call your doctor. And see your doctor right away if you have difficulty breathing, develop a bluish color in your lips and fingertips, have chest pain, a high fever, or a cough with mucus that is severe or is getting worse.

It's especially important to get medical attention for pneumonia if you are in a high-risk group, including adults older than age 65, children age two or younger, people with an underlying health condition or weakened immune system. For some of these vulnerable individuals, pneumonia can quickly become a life-threatening condition.

How Is Pneumonia Diagnosed?

Sometimes pneumonia can be difficult to diagnose because the symptoms are so variable, and are often very similar to those seen in a cold or influenza. To diagnose pneumonia, and to try to identify the germ that is causing the illness, your doctor will ask questions about your medical history, do a physical exam, and run some tests.

Medical history

Your doctor will ask you questions about your signs and symptoms, and how and when they began. To help figure out if your infection is caused by bacteria, viruses or fungi, you may be asked some questions about possible exposures, such as:

Any recent travel

Your occupation

Contact with animals

Exposure to other sick people at home, work or school

Whether you have recently had another illness

Physical exam

Your doctor will listen to your lungs with a stethoscope. If you have pneumonia, your lungs may make crackling, bubbling, and rumbling sounds when you inhale.

Diagnostic Tests

If your doctor suspects you may have pneumonia, they will probably recommend some tests to confirm the diagnosis and learn more about your infection. These may include:

Blood tests to confirm the infection and to try to identify the germ that is causing your illness.

to confirm the infection and to try to identify the germ that is causing your illness. Chest X-ray to look for the location and extent of inflammation in your lungs.

to look for the location and extent of inflammation in your lungs. Pulse oximetry to measure the oxygen level in your blood. Pneumonia can prevent your lungs from moving enough oxygen into your bloodstream.

to measure the oxygen level in your blood. Pneumonia can prevent your lungs from moving enough oxygen into your bloodstream. Sputum test on a sample of mucus (sputum) taken after a deep cough, to look for the source of the infection.

If you are considered a high-risk patient because of your age and overall health, or if you are hospitalized, the doctors may want to do some additional tests, including: