How Does Pneumonia Affect The Lungs

About pneumonia?

Pneumonia is an acute respiratory infection of the lung. Lungs are made up of small sacs called alveoli. In a healthy person, each alveolus is filled with air when the person breathes. In the condition of pneumonia, the alveoli are filled with fluid and pus. That's why a person with pneumonia experiences pain when breathing.1

What causes pneumonia?

The air that we breathe contains a wide variety of viruses, bacteria, and fungi that can cause pneumonia. It is important to know the exact causes of pneumonia to get proper treatment. 


Bacterial pneumonia can occur on its own or can be developed after a viral infection. When bacterial pneumonia affects one or more sections of the lung causes a condition called lobar pneumonia. 

The most common type of bacterial pneumonia is pneumococcal pneumonia which is caused by a bacterium called Streptococcus pneumoniae. This bacterium is usually found in the upper respiratory tract. 

People who have respiratory disease or viral infection, are recovering from surgery, or have weakened immune systems have a major risk of contracting bacterial pneumonia.2 

Other types of bacteria cause atypical pneumonia (have different symptoms and different appearance on chest X-ray). Theses include:2 

  • Mycoplasma pneumonia: infects people who work and live in crowded conditions and are younger than 40 years old. It causes mild pneumonia, referred to as walking pneumonia
  • Chlamydophila pneumoniae: it causes upper respiratory tract infection year-round resulting in mild pneumonia. 
  • Legionella pneumophila: causes Legionnaire's disease, a dangerous form of pneumonia. Don’t pass from person to person. Results from exposure to contaminated water from an outdoor fountain, whirlpool spas, and cooling towers. 


Viral pneumonia is not serious and infects the upper respiratory tract. The most common viral pneumonia in adults is SARS-CoV-2 (the virus that causes COVID-19) and the influenza virus. COVID-19 pneumonia affects both lungs and can be severe, causing acute respiratory distress syndrome (ARDS), a respiratory failure caused by low oxygen levels in the blood. 

Pneumonia caused by the influenza virus may also be severe. The most common cause of viral pneumonia in young children is a respiratory syncytial virus (RSV).2


Fungal pneumonia is most common in people with:2 

  • Weakened immune system (due to HIV/AIDS or the long-term use of medicines, such as those used to treat cancer or manage organ transplants that suppress the immune system) 
  • Chronic health problems 
  • Exposure to a large number of fungi from contaminated bird dropping or soil 

A serious fungal infection caused by Pneumocystis jirovecii is pneumocystis pneumonia (PCP), which occurs in people who have a weak immune system.2 Other fungi include: 

  • Coccidioidomycosis - caused by valley fever. 
  • Cryptococcus - fungus found in bird droppings and contaminated soil. 
  • Histoplasmosis

Symptoms of pneumonia 

Symptoms of bacterial pneumonia include:3 

  • Fever 
  • Cough that produces mucus (bloody, yellow, or green)
  • Heavy sweating 
  • Loss of appetite 
  • Rapid breathing and pulse 
  • Chills 
  • Sharp chest pain which is worse with coughing and deep breathing 
  • Shortness of breath which is worse with exercise 
  • Bluish color of the lip and fingernails 
  • Confused mental state or delirium, especially in older people 

Symptoms of viral pneumonia same as bacterial pneumonia may be followed by:3 

  • Headache 
  • Muscle pain 
  • Weakness 
  • Increase shortness of breath 
  • Worsening of the cough 

Some infrequent types of pneumonia might have different symptoms (eg. Mycoplasma pneumonia), such as a severe cough that produces mucus.3

Is pneumonia curable?

Yes, pneumonia is curable and it's important to get treatment for pneumonia because it can be serious. Treatment of pneumonia depends on the severity and type of pneumonia. If you have mild pneumonia you can manage it at home, but if you have severe pneumonia, you need to go to the hospital and get treatment.4 

Treatment and prevention 

Treatment of pneumonia depends on:5

  • The age of the person 
  • The severity of the disease 
  • The cause of pneumonia 
  • Baseline health condition 

The goal of the therapy is to cure the infection and prevent/treat complications. 

  • Bacterial pneumonia is treated with antibiotics. If there is an improvement within a couple of days, antibiotics must continue as per medical prescription in order to prevent bacterial resistance. 
  • Viral pneumonia does not respond to typical antibiotics; instead it is treated by antiviral therapy. 

People with mild pneumonia might be able to manage it at home by:5 

  • Drinking plenty of fluid 
  • Getting a lot of rest 
  • Drinking warm beverages 
  • Following medical recommendations - whether or not to take cough medicine should be discussed with a doctor. 

People with severe pneumonia will need to receive treatment at the hospital where intravenous fluids, antibiotics, and oxygen therapy can be administered.

Pneumonia can be prevented by:6

  1. Wash hands after coughing. 
  2. Avoid smoking - Tobacco damages the lungs. People who smoke have a high risk of getting pneumonia. 
  3. Being aware of general health:
  • Good health habits, rest and regular exercise help promote faster recovery. 
  • Keep existing health conditions well-managed, like asthma, diabetes, chronic obstructive pulmonary disease, and heart disease.
  1. Get vaccinated: Get a flu shot yearly to prevent seasonal influenza. If you have a child, talk to your doctor about:
  • The Hib vaccine - prevents children from developing pneumonia caused by Haemophilus influenzae type B. 
  • A drug called Synagis (palivizumab) - prevents pneumonia cases caused by a respiratory syncytial virus.

When to seek medical attention?

The majority of people recover from pneumonia and return to good health. Some people with severe diseases will not survive the residue with the best available care. Older people and people who have health problems have a high risk of developing severe or fatal pneumonia. If you feel that your symptoms are getting worse or have a risk of developing severe pneumonia, you must seek medical attention.4


Pneumonia is an acute respiratory infection of the lung. It can be caused by bacteria, viruses, or fungi. The main symptoms include fever, a cough that produces mucus (bloody, yellow, or green), heavy sweating, loss of appetite, rapid breathing and pulse, chills, sharp chest pain that worsens with coughs, shortness of breath that worsens with exercise, bluish color of the lips and fingernails and confused mental state or delirium, especially in older people. Treatment of pneumonia depends on the type and severity of the disease. It can be prevented by getting vaccinated.


  1. Pneumonia in children [Internet]. Available from:
  2. American Lung Association. What causes pneumonia? [Internet]. Available from:
  3. John Hopkins Medicine. Pneumonia [Internet]. Available from:
  4. How is pneumonia diagnosed and treated? - British Lung Foundation [Internet]. Asthma + Lung UK. 2015. Available from:
  5. Pneumonia Treatment and Recovery [Internet]. Available from: 
  6. American Lung Association. Preventing pneumonia [Internet]. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Malaz Ameer Ata Almanan

Medical Student - University of Bahri, Khartoum, Sudan

Malaz Ameer Ata Almanan Mohammed. 4th year medical student. Researcher enthusiast. Passionate about ophthalmic surgery. I would like to be ophthalmologist.

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