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Southern Cross Medical Library

The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross. For more articles go to the Medical Library index page.

Pneumonia - causes, symptoms, treatment

Pneumonia is a bacterial or viral infection of the lungs.  Symptoms can include fever, chills, shortness of breath, coughing that produces phlegm, and chest pain. 
Pneumonia can usually be treated at home with antibiotics but some cases may require time in hospital and can result in death.  Vaccines are available against some of the more common infectious agents that cause pneumonia.


Pneumonia is an infection of the air sacs in the lungs and is caused by bacteria, viruses or, rarely, fungi. Most cases of pneumonia are caused by bacteria, usually Streptococcus pneumonia (pneumococcal disease) but viral pneumonia is more common in children.
The lungs are made up of separate lobes – three in the right lung and two in the left lung. Pneumonia may affect only one lobe or be widespread in the lungs.
Anyone can develop pneumonia but some groups are at greater risk:

  • Babies and toddlers - particularly those born prematurely
  • People who have had a recent viral infection - such as a cold or influenza (the flu)
  • Smokers
  • People with chronic lung conditions such as asthma, bronchitis or bronchiectasis
  • People with suppressed or weak immune systems
  • People who have poor diets or are undernourished
  • People who drink excessive alcohol
  • Patients in hospital
  • People who have had swallowing or coughing problems following a stroke, concussion or other brain injury
  • People aged 65 years or older.
Pneumonia can develop when a person breathes in small droplets that contain pneumonia-causing organisms. It can also occur when bacteria or viruses that are normally present in the mouth, nose and throat enter the lungs.

Signs and symptoms

Viral pneumonia tends to develop slowly over a number of days, whereas bacterial pneumonia usually develops quickly, often over a day.
Most people who develop pneumonia initially have a viral infection such as a cold or flu, which produces symptoms such as headache, muscle aches and fever. If pneumonia develops, symptoms commonly include: 

  • Fever
  • Chills
  • Shortness of breath
  • Rapid breathing
  • A worsening cough that may produce yellow/green or bloody mucus (phlegm)
  • Chest pain when breathing or coughing – caused by inflammation of the membrane that lines the lungs.
In babies and children, symptoms may be less specific and they may not show clear signs of a chest infection. Commonly they will have a fever, appear unwell, and become lethargic. They may also have noisy or rattly breathing, have difficulty with feeding and make a grunting sound with breathing.
People older than age 65 years with pneumonia may show signs of confusion or reduced mental awareness.
It is also possible for the skin, lips and nail beds to become dusky or bluish. This is a sign that the lungs are unable to deliver enough oxygen to the body. If this occurs it is vital to seek medical assistance straight away.


If pneumonia is suspected it is important to seek medical attention promptly so that an accurate diagnosis can be made and appropriate treatment given.
The doctor will take a medical history and will conduct a physical examination. During the examination the doctor will listen to the chest with a stethoscope. Coarse breathing, crackling sounds, wheezing and reduced breath sounds in a particular part of the lungs can indicate pneumonia.
A chest x-ray is usually taken to confirm the diagnosis; it will show the areas of the lung affected by the pneumonia. Blood tests may also be taken and a sample of the sputum may be sent to the laboratory for testing.


Most cases of pneumonia can be treated at home. However, babies, children, and people with severe pneumonia may need to be admitted to hospital for treatment.
Pneumonia is usually treated with antibiotics, even if viral pneumonia is suspected as there may be a degree of bacterial infection as well. The type of antibiotic used and the way it is given will be determined by the severity and cause of the pneumonia.
Home-based treatment usually includes: 

  • Antibiotics - given by mouth as tablets or liquid
  • Pain-relieving medications
  • Paracetamol to reduce fever
  • Drinking plenty of fluids, especially water, to help loosen mucus in the lungs
  • Rest.

Hospital-based treatment usually includes: 

  • Antibiotics given intravenously (via a drip into a vein)
  • Oxygen therapy - to ensure the body gets the oxygen it needs
  • Intravenous fluids - to correct dehydration or if the person is too unwell to eat or drink
  • Physiotherapy - to help clear the sputum from the lungs.


Pneumonia may take several weeks to fully recover from. The cough may continue until the mucus has been cleared from the lungs. This is a part of the recovery process. Fatigue and a reduced ability to exercise may also be experienced.
If the cough gets worse or recovery is taking longer than several weeks, see a doctor for further assessment. Smokers should have a chest x-ray after six weeks to confirm complete clearance of the lungs.


The following steps can be taken to reduce the risk of contracting pneumonia:

  • Breastfeeding your baby (preferably beyond four months) – to help boost their immune system
  • Quit smoking and ensure a smoke-free household
  • Keeping your home warm and well-ventilated
  • Vaccination, in particular against pneumococcal disease, whooping cough , Hib (Haemophilus influenza type b), and influenza
  • Regular and thorough hand-washing
  • Avoiding contact with people who have colds, the flu, or other infections.

Vaccines against pneumococcal disease may not always prevent pneumonia but they may prevent serious complications of pneumonia should infection occur.

Further information and support

For further information and advice about pneumonia contact your GP, practice nurse, or call:

Freephone: 0800 611 116 (operates 24 hours a day, 7 days a week)

Freephone: 0800 933 922 (operates 24 hours a day, 7 days a week) 
Immunisation Advisory Centre
Freephone: 0800 IMMUNE (0800 466 863)


Kidshealth (2017). Pneumonia (Web Page). Wellington: Paediatric Society of New Zealand. Auckland: Starship Foundation. [Accessed: 29/04/19] 
Mayo Clinic (2018). Pneumonia (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research.  [Accessed: 29/04/19]National Heart, Lung, and Blood Institute (Year not stated).
Pneumonia (Web Page). Bethesda, MD: National Institute of Health. [Accessed: 29/04/19]
O’Toole, M.T. (Ed.) (2017). Pneumonia. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.
Last Reviewed – May 2019


Go to our Medical Library Index Page to find information on other medical conditions.