Picture of lungs with Pneumonia

What is Pneumonia?

One of the most common causes of mortality worldwide and in Singapore, is pneumonia – approximately 20% of deaths in Singapore is caused by pneumonia1. Pneumonia is an acute infection of the respiratory tract and is most common in young children and the elderly2. It can range from mild to severe and may occur in one or both lungs.

To understand how pneumonia works, we must first understand how breathing works. When you breathe, air goes in either through your nose or mouth. The air then makes its way down to your throat and eventually your lungs. Within your lungs are small airways known as bronchioles and alveoli. Once air reaches the alveoli, it is transferred to your blood which then disseminates it all over the body. However, when someone has pneumonia, this intricate process is disrupted. In pneumonia, the alveoli or air sacs get filled with fluid or pus, making it difficult to breathe. 

Pneumonia can be classified into 4 categories, these are3:

  • Hospital-acquired pneumonia (HAP): bacterial pneumonia that can be acquired during a hospital visit or stay. This type of pneumonia is often more serious as the bacteria may be a drug-resistant strain.
  • Community-acquired pneumonia (CAP): pneumonia acquired from settings outside the hospital.
  • Ventilator-acquired pneumonia (VAP): pneumonia acquired by individuals who use a ventilator.
  • Aspiration pneumonia: acquired by inhaling bacterial pneumonia into your lungs from food, drinks, vomit, or saliva.
Illustration of normal vs lung with pneumonia

What causes Pneumonia?

In addition to the different ways or settings in which pneumonia may be acquired, there are number of causes of pneumonia, these are4:

  • Bacteria: streptococcus pneumoniae (most common), mycoplasma pneumoniae (causes a mild form of pneumonia known as walking pneumonia, chlamydia pneumoniae, and Legionella pneumoniae5.
  • Viruses: any virus that results in a respiratory infection can cause pneumonia (for example, influenza, rhinoviruses, COVID-19)6.
  • Fungi: the most uncommon cause of pneumonia, fungus or mold spores can become airborne and cause pneumonia7.

These causes of pneumonia may be acquired in many different settings, but hospital-acquired and ventilator-acquired bacterial pneumonia is of great concern as they are often resistant to antibiotics, making them difficult to eliminate, they are responsible for a significant number of deaths in hospitals or carehomes8.

What are the common symptoms?

The symptoms of pneumonia range from mild to severe, depending on the cause of pneumonia and how healthy you are. Symptoms include:

  • Cough which may or may not produce phlegm
  • Fever
  • Sweating or chills
  • Loss of appetite
  • Nausea or vomiting
  • Headaches
  • Chest pains which worsen when you cough or breathe
  • Breathlessness 
  • Lethargy or fatigue

Is Pneumonia painful?

Yes, pneumonia can cause chest pains that worsen when you breathe or cough.

Who is at risk of Pneumonia in Singapore?

Individuals with the following factors have an increased risk of pneumonia:

  • Young children: from birth to 2 years.
  • Elderly: aged 65 and older.
  • Weakened immune systems: pregnant women, HIV positive people, people who are undergoing treatment for cancer.
  • Chronic medical conditions: bronchiectasis, asthma, cystic fibrosis, chronic obstructive pulmonary disease (COPD), heart failure, sickle cell disease, kidney disease, liver disease, uncontrolled diabetes, pulmonary fibrosis, sarcoidosis, etc. 
  • Hospitalised: individuals who are hospitalised are at a high risk of hospital-acquired pneumonia.
  • Smokers: smoking causes damage to the lungs which can make you more susceptible to pneumonia.

How is Pneumonia diagnosed in Singapore?

After a physical examination, pneumonia can be diagnosed using the following tests:

  • X-ray: an x-ray of your chest will be taken and from there, your respiratory specialist will be able to identify any areas of inflammation.
  • Sputum culture: your phlegm will be tested for the cause of inflammation, whether it is bacterial, viral, or fungal.
  • Pulse oximeter: a sensor is placed on your finger to check the amount of oxygen present in your blood.
  • Computed tomography scan (CT-scan): like an x-ray but clearer and more detailed, a more accurate picture of your lungs can be seen for signs of pneumonia.
  • Bronchoscopy: a long, thin tube with a camera and light attached on one end will be inserted and gently guided down your throat and into your lungs, to check for signs of pneumonia.
  • Fluid sample: if there is fluid in the spaces surrounding your lungs, a fluid sample may be taken to identify the cause of infection.

What are the treatment options for Pneumonia in Singapore?

The type of treatment you receive will depend on the type of pneumonia you have, its severity, and your health. Treatment options include:

  • Medications: antibiotics for bacterial infections, antivirals for viral infections, and antifungal for fungal infections.
  • Oxygen therapy: helps to maintain oxygen levels in your blood.
  • Respiratory therapy: delivering specific medications directly to your lungs or breathing exercises to optimise oxygenation.

Frequently asked questions

Is pneumonia contagious?

Bacterial and viral pneumonia are contagious and can be passed between individuals.

How do I prevent pneumonia?

Getting vaccinated against influenza, pneumococcal pneumonia, diphtheria or whooping cough, and COVID-19, can help reduce your risk of pneumonia. Maintain good hygiene habits and stop smoking and vaping.

Does pneumonia go away by itself?

Occasionally, very mild forms of pneumonia can go away by itself without any medication


  1. Health Hub. (2022, September 22). Principal Causes of Death. Retrieved from Health Hub: https://www.healthhub.sg/a-z/health-statistics/4/principal-causes-of-death 
  2. J H Reynolds, G. M. (2010). Pneumonia in the immunocompetent patient. The Britisih Journal of Radiology, 998-1009.
  3. Normandin, B. (2021, November 10). Everything You Need to Know About Pneumonia. Retrieved from healthline: https://www.healthline.com/health/pneumonia 
  4. Cleveland Clinic Medical Professional. (2020, June 15). Pneumonia. Retrieved from Cleveland Clinic: https://my.clevelandclinic.org/health/diseases/4471-pneumonia 
  5. R D Meyer, R. G. (1992). Community-acquired pneumonia. Journal of Hospital Infection.
  6. Olli Ruuskanen, E. L. (2011). Viral pneumonia. Lancet, 1264-1275.
  7. Davies, S. F. (1994). Fungal pneumonia. The Medical Clinics of North America, 1049-1065
  8. Anita Rae Modi, C. S. (2020). Hospital-acquired and ventilator-associated pneumonia: Diagnosis, management, and prevention. Cleveland Clinic Journal of Medicine, 633-639.
WALK IN Mount Elizabeth Medical Centre, 3 Mount Elizabeth, #05-05, Singapore 228510
© Copyright 2024. All rights reserved | Interventional Pulmonology & Lung Clinic