Chest conditionsDisease, Condition & InjuryLungs


(Community-Acquired Pneumonia; CAP; Bronchopneumonia)

Pneumonia – Definition

Pneumonia is an infection of the lungs. It affects the small airways and air sacs in the lungs.

Pneumonias are sometimes described by where and how you were infected, for example:

  • Community-acquired pneumonia — acquired in the community (eg, at school, work, gym)
  • Nosocomial pneumonia — acquired in a hospital
  • Aspiration pneumonia — happens when a foreign matter, like often stomach content, is inhaled

Pneumonia – Causes

Pneumonia may be caused by:

  • Bacteria
  • Virus — flu virus is common cause
  • Other specific germs Atypical pneumonia
  • Fungus — common in people with immuncompromised conditions like AIDS

Pneumonia – Risk Factors

Factors that increase your chance of pneumonia include:

  • Age: Infants, young children and older adults
  • Living in crowded living conditions (eg. dormitories, nursing homes)
  • Smoking
  • Alcohol or drug abuse
  • Trouble swallowing or coughing
  • Having certain lung conditions:
    • Asthma
    • Chronic obstructive pulmonary disease
    • Cystic fibrosis
    • Being on a ventilator
  • Heart disease
  • Diabetes
  • Weakened immune system
  • Malnutrition
  • Chronic exposure to certain chemicals (eg, work in construction or agriculture)

Pneumonia – Symptoms

Symptoms of pneumonia may include some or all of the following:

  • Cough
  • Increased phlegm production
  • Fever and chills
  • Trouble breathing
  • Chest pain
  • Weakness

Pneumonia – Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. To look for an infection or sepcific causes of the infection your doctor may ask for:

  • Blood tests
  • Urine tests
  • Blood cultures
  • Sputum test — exam of phlegm

Your doctor may also need to take detailed pictures of your lungs. This is done with a chest x-ray.

Pneumonia can cause problems with breathing. This may make it difficult for you to get enough oxygen. To measure the level of oxygen in your blood your doctor may do the following tests:

  • Pulse oximetry
  • Arterial blood gas

Pneumonia – Treatment

Treatment of pneumonia depends on:

  • What caused the pneumonia
  • Severity of symptoms
  • Other factors, like your overall health

People with severe pneumonia may need to be hospitalized.


Common treatment approaches include:

  • Antibiotics — for pneumonia caused by bacteria
    • Note: Antibiotics are ineffective for treating viral pneumonia.
  • Antiviral medications — for pneumonia caused by a virus in young children and people with weakened immune systems

It is very important to take the medication as prescribed. Stopping medication early may cause a relapse. It may also create a strain of drug resistant bacteria. An infection with a drug resistant bacteria can be more severe and harder to cure.

Home Care

These steps will help you stay strong while you recover:

  • Get plenty of rest and drinking lots of fluids
  • Eat a healthy diet. It should include lots of fruits and vegetables.
  • If you do not get enough vitamin C in your diet, ask your doctor about a supplement. This may be beneficial for some.
  • Take over-the-counter medication to reduce fever, and aches.

Pneumonia – Prevention

Certain vaccines may prevent pneumonia:

  • Flu shot — pneumonia may be a complication of the flu for people at high risk, particularly the elderly
  • Pneumococcal vaccine — General recommendations for this vaccine include:
    • PCV vaccine series for children
    • PPSV for adults aged 65 years and older and for younger people who have a high risk of infection
  • Haemophilus influenzae vaccine — to protect against a bacteria that can cause pneumonia or meningitis, recommeded for
    • Children in the United States who are younger than 5 years old
    • Often is given to infants starting at 2 months of age

Other preventive measures include:

  • Avoid smoking. Smoke weakens the lungs’ resistance to infection.
  • Avoid close contact with people who have the cold or flu.
  • Wash your hands often.
  • Protect yourself on jobs that include chemicals or other lung irritants.
  • Eat a healthy diet. If you do not get enough vitamin C or zinc in your diet, ask your doctor if you should take these supplements.
  • Get adequate rest.
  • Exercise regularly.

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