Pneumonia is a lung infection that causes inflammation of the air sacs. The inflamed air sacs may fill with mucus or fluid, causing the patient to cough with phlegm, have fever, and difficulty of breathing.  Bacteria, viruses, or fungi may be the agent that causes the infection in pneumonia.

Pneumonia can affect anyone. But the two age groups at highest risk are:

  • Children who are 2 years old or younger developing
  • People who are age 65 or older
  • Chronic disease
  • Weakened or suppressed immune system
  • Smoking
  • Being hospitalized

Pneumonia usually starts when you breathe the germs into your lungs. You may be more likely to get the disease after having a cold or the flu. These illnesses make it hard for your lungs to fight infection, so it is easier to get pneumonia.

It often clears up in 2 to 3 weeks. But older adults, babies, and people with other diseases can become very ill. They may need to be in the hospital.

Pneumonia can be classified in many different ways.  It can be based upon:

Manner of acquisition

  • Community-acquired pneumonia. This type developed outside the hospital.  This is the more common type of pneumonia.
  • Hospital-acquired pneumonia. This type occurs when an individual is hospitalized for another condition then acquires pneumonia.  This is more serious because it develops in immunocompromised patients.
  • Aspiration pneumonia. This is caused by the inhalation of food or drink, saliva, or vomit in the lungs

The way inflammatory cells infiltrate the tissue

  • Bronchopneumonia. Appears as patchy infiltrates of inflammation in the air sacs throughout the lungs, in the X-ray film.
  • Lobar pneumonia. This affects one lobe of the lung including all the air sac in that lung.
  • Lipoid Pneumonia. This is characterized by the accummulation of fats in the air sacs.

Type of organism that causes inflammation

  • Bacterial pneumonia. The most common organism that causes pneumonia is the Streptococcus pneumoniae .  Other bacteria that causes the atypical type of pneumonia are the Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumonia.

Symptoms of pneumonia caused by bacteria in otherwise healthy people younger than 65 usually come on suddenly.  Symptoms may include:

  • Cough, often producing mucus, that appear rusty or green or tinged with blood
  • Fever
  • Shaking or chills.
  • Fast, often shallow, breathing
  • Feeling of being short of breath
  • Chest wall pain that is often made worse by coughing or breathing in
  • Fast heartbeat
  • Feeling very tired or weak
  • Nausea and vomiting
  • Diarrhea

Nonbacterial pneumonia. This may be due to viruses, such as Influenza virus, respiratory syncitial virus, and other viruses; or it may be due to fungi, incuding Cryptococcus, Histoplasma, and

Symptoms of pneumonia not caused by bacteria may come on gradually and are often not as bad or as obvious as symptoms of bacterial pneumonia. Symptoms may include:

  • Fever
  • Cough
  • Shortness of breath
  • Little mucus when you cough

In children, symptoms may depend on age:

  • In infants younger than 1 month of age, symptoms may include having little or no energy (lethargy), feeding poorly, grunting, or having a fever.
  • In children, symptoms of pneumonia are often the same as in adults. Your doctor will look for signs such as cough and a breathing rate over 60 breaths a minute.


The diagnosis of pneumonia always begins with taking a medical history and performing a physical examination to look for characteristic signs. In particular, listening to the lungs may reveal areas where sound is diminished, wheezing, or crackling sounds in affected areas. Some commonly performed diagnostic tests are as follows:

  • Chest X-ray. This helps your doctor diagnose pneumonia and determine the extent and location of the infection.
  • Blood tests. Blood tests are used to confirm infection and to try to identify the type of organism causing the infection.
  • Pulse oximetry. This measures the oxygen level in your blood.
  • Sputum test. A sample of fluid from yourlungs (sputum) is taken after a deep cough and analyzed to help pinpoint the cause of the infection.
  • Pleural fluid culture. A fluid sample is taken by putting a needle between your ribs from the pleural area and analyzed to help determine the type of infection.
  • CT scan. If your pneumonia isn’t clearing as quickly as expected, your doctor may recommend a chest CT scan to obtain a more detailed image of your lungs.



Specific treatments depend on the type and severity of your pneumonia, your age and your overall health. The options include:

  • Antibiotics. These medicines are used to treat bacterial pneumonia. It may take time to identify the type of bacteria causing your pneumonia and to choose the best antibiotic to treat it.
  • Fever reducers. These include drugs such as aspirin, ibuprofen (Advil, Motrin IB, others) and acetaminophen (Tylenol, others).
  • Cough medicine. This medicine may be used to calm your cough so that you can rest. Because coughing helps loosen and move fluid from your lungs, it’s a good idea not to eliminate your cough completely.


You may need to be hospitalized if:

  • You are older than age 65
  • You become confused about time, people or places
  • Your nausea and vomiting prevent you from keeping down oral antibiotics
  • Your blood pressure drops
  • Your breathing is rapid
  • You need breathing assistance
  • Your temperature is below normal
  • Your heart rate is below 50 or higher than 100

You may be admitted to the intensive care unit if you need to be placed on a breathing machine (ventilator) or if your symptoms are severe.

Children may be hospitalized if they:

  • Are younger than age 2 months
  • Are excessively sleepy
  • Have trouble breathing
  • Have low blood oxygen levels
  • Appear dehydrated
  • Have a lower than normal temperature

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