This website is for informational use only and does not provide any medical advice.

What is pneumonia?

Pneumonia is a lung infection. Patients with pneumonia can have a cough with green or bloody mucus, a fever, chills, chest pain and difficulty breathing.


Symptoms of pneumonia include:

  • Confusion, especially in older people
  • Cough
  • Discomfort Excess sweating and clammy skin
  • Fever, which may be mild or high
  • Headache
  • Loss of appetite
  • Shaking chills
  • Sharp or stabbing chest pain that gets worse when you breathe deeply or cough
  • Shortness of breath


Pneumonia can be caused by bacteria, viruses and fungi. Your body generally prevents germs from infecting your lungs but some germs can overwhelm your immune system leading to an infection.

The most common type of pneumonia is community-acquired pneumonia – pneumonia that is contracted outside of the hospital or another healthcare setting. It can be caused by bacterium called streptococcus pneumonia or pneumocystis jiroveci, as well as the flu virus.

Hospital-acquired pneumonia or healthcare-acquired pneumonia is a lung infection that occurs when in the hospital or another healthcare facility such as a rehabilitation center or a nursing home.

Risk factors

Patients with the following conditions may be at greater risk for contracting pneumonia:

  • Chronic lung disease (COPD, bronchiectasis, cystic fibrosis)
  • Cigarette smoking
  • Dementia, stroke, brain injury, cerebral palsy, or other brain disorders
  • Immune system problem (during cancer treatment, or due to HIV/AIDS, organ transplant, or other diseases)
  • Other serious illnesses, such as heart disease, liver cirrhosis, or diabetes
  • Recent surgery or trauma
  • Surgery to treat cancer of the mouth, throat, or neck