What is Pneumonia and What are the Main Causes of Pneumonia?


Pneumonia is an inflammation of the lungs most often caused by infection with bacteria or a virus. Pneumonia can make it hard to breathe because the lungs have to work harder to get enough oxygen into the bloodstream.

People with pneumonia usually complain of coughing, fever, shortness of breath, and chest pain.

Your body’s immune system usually keeps bacteria from infecting your lungs. In bacterial pneumonia, bacteria reproduce in your lungs, while your body tries to fight off the infection. This response to bacterial invaders is called inflammation.

When the inflammation occurs in the alveoli (microscopic air sacs in the lungs), they fill with fluid. Your lungs become less elastic and cannot take oxygen into the blood or remove carbon dioxide from the blood as efficiently as usual.When the alveoli don’t work efficiently, your lungs have to work harder to satisfy your body’s need for oxygen. This causes the feeling of being short of breath, which is one of the most common symptoms of pneumonia. Inflammation causes many of the other symptoms, including fever and chest pain.

What are the main types of pneumonia?

Pneumonia is often divided into two main categories (‘community-acquired pneumonia’ and ‘hospital-acquired pneumonia’) depending on whether you were infected while living at home (in the community) or while staying in hospital.

What are the main causes of pneumonia?

There are about 30 different causes of pneumonia. However, they all fall into one of these categories:

Infective pneumonia: Inflammation and infection of the lungs and bronchial tubes that occurs when a bacteria (bacterial pneumonia) or virus (viral pneumonia) gets into the lungs and starts to reproduce.

Aspiration pneumonia: An inflammation of the lungs and bronchial tubes caused by inhaling vomit, mucous, or other bodily fluids. Aspiration pneumonia can also be caused by inhaling certain chemicals.

White blood cells (leukocytes), a key part of your immune system, begin to attack the invading organisms. The accumulating pathogens, white cells and immune proteins cause the air sacs to become inflamed and filled with fluid, leading to the difficult breathing that characterizes many types of pneumonia. If both lungs are involved, it’s called double pneumonia.

Viruses, bacteria, or (in rare cases) parasites or other organisms cause pneumonia.

In most cases, the specific organism (such as bacteria or virus) cannot be identified even with testing. When an organism is identified, it is usually the bacteria Streptococcus pneumoniae.

Other bacteria that may cause pneumonia include Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila (the bacteria that cause Legionnaires’ disease), Staphylococcus aureus, Moraxella catarrhalis, Streptococcus pyogenes, Neisseria meningitidis, or Klebsiella pneumoniae. Mycoplasma pneumonia is sometimes mild and called walking pneumonia.

Some other reasons of causing pneumonia:

Viral infection
Bacterial infection:
Streptococcus pneumonia
Staphylococcus aureus
Chlamydia pneumoniae
Mycoplasma pneumoniae
Pneumocystis carinii
Toxoplasma gondii
Fungal infection
Lung cancer- can cause recurrent pneumonia
AIDS- can lead to recurring lung infections
hemophilus influenza
mycoplasma pneumonia
staphyloccus aureus
streptococcus pneumonia
pneumocystis carinii
acid fast bacillus