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Alternative names

Bacterial Pneumonia


An inflammation of the lungs caused by an infection.

Causes, incidence, and risk factors

Pneumonia is a very common, serious illness and affects about 1 out of 100 people each year. It is caused by many different organisms and can range in seriousness from mild to life-threatening illness. There are different categories of pneumonia.
Two of these types are hospital-acquired and community-acquired. Common types of community-acquired pneumonia are pneumococcal pneumonia and Mycoplasma pneumonia. In some people, particularly the elderly and those who are debilitated, pneumonia may follow INFLUENZA. Hospital-acquired pneumonia tends to be more serious because defense mechanisms against infection are often impaired.

Some of the specific pneumonia-related disorders include:

  • Aspiration pneumonia
  • Atypical pneumonia
  • Bacterial pneumonia
  • Chlamydial pneumonia (c. trachomatis)
  • Chlamydial pneumonia (psittacosis)
  • CMV pneumonia
  • Eosinophilic pneumonia

also called acute pulmonary eosinophilia (Loeffler’s syndrome)

  • Hospital-acquired pneumonia
  • Hydrocarbon pneumonia
  • Hypersensitivity pneumonitis
  • Legionella pneumonia
  • Mycoplasma pneumonia (walking pneumonia)
  • Necrotizing pneumonia
  • Pediatric pneumonia
  • Pneumocystis carinii pneumonia
  • Pneumonia in immunocompromised host
  • Pneumonia with lung abscess
  • Pyogenic pneumonia
  • Viral pneumonia


Vaccination (flu vaccine, pneumovax) may be helpful in preventing some types of pneumonia. Coughing and deep breathing may help prevent some forms of hospital-acquired pneumonia. See also the specific types of pneumonia.


  • Coug
  • With mucus-like, greenish, or pus-like sputum
  • Chills with shaking
  • Fever
  • Easy fatigue
  • Chest pain
  • Sharp or stabbing
  • Increased by deep breathing
  • Increased by coughing
  • Headache
  • Loss of appetite
  • Nausea and vomiting
  • General discomfort, uneasiness, or ill feeling (malaise)
  • Joint stiffness(rare)
  • Muscular stiffness(rare)
  • Rales

Additional symptoms that may be associated with this disease:

  • Shortness of breath
  • Sweating, excessive
  • Skin, clammy
  • Nasal flaring
  • Coughing up blood
  • Breathing, rapid
  • Breathing, absent temporarily
  • Anxiety, stress, and tension
  • Abdominal pain

Signs and Tests

Crackles are heard when listening to the chest with a stethoscope (auscultation).

Tests include:

  • A chest X-ray
  • A sputum gram stain
  • A CBC
  • Arterial blood gases

This disease may also alter the results of the following tests:

  • Thoracic CT
  • Routine sputum culture
  • Pulmonary ventilation/perfusion scan
  • Pleural fluid culture
  • Lung needle biopsy


The goal of treatment is to cure the infection with antibiotics. If the pneumonia is caused by a virus, antibiotics will not be effective.
Supportive therapy includes oxygen and respiratory treatments to remove secretions, if indicated.

Expectations (prognosis)

Most patients will respond to the treatment and improve in two weeks. Elderly or debilitated patients who fail to respond to treatment may die from respiratory failure.

  • Acute respiratory failure
  • Empyema

Calling your health care provider

Call Your health care provider if symptoms of pneumonia develop.


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