Overview
Pneumonia is an infection of the lungs. Unlike diseases with one specific cause, pneumonia can be triggered by many different germs, bacteria, viruses, fungi, and occasionally parasites, and the right treatment depends heavily on which type is involved.
Disease Summary
- Category
- Infectious Disease
- Cause
- Bacteria, viruses, fungi, or parasites, most commonly Streptococcus pneumoniae or respiratory viruses
- Transmission
- Varies by cause; often through respiratory droplets, or arising from an existing respiratory infection
- Body System
- Respiratory
- Preventable
- Yes
- Curable
- Yes
Symptoms
Common Symptoms
Most people with pneumonia experience one or more of the following symptoms.
Cough
Often produces mucus, which may be yellow, green, or blood-tinged.
Fever
Fever, chills, and sweating commonly accompany pneumonia.
Difficulty Breathing
Shortness of breath, particularly during activity, is common even in milder cases.
Chest Pain
Sharp or stabbing chest pain that often worsens with deep breathing or coughing.
Fatigue
Tiredness and low energy are common, particularly in older adults.
Danger Signs
Seek urgent medical attention immediately if any of the following symptoms develop.
Severe Difficulty Breathing
Rapid or laboured breathing may indicate the infection is affecting a large portion of the lungs.
Confusion
New confusion, especially in older adults, can indicate severe infection and requires urgent evaluation.
Bluish Lips or Face
A sign that the blood may not be carrying enough oxygen, a medical emergency.
Rapid Heartbeat or Low Blood Pressure
May indicate the infection is affecting the whole body and requires immediate care.
Diagnosis
Clinical Assessment
Diagnosis begins with listening to the lungs for abnormal sounds, along with evaluating symptoms and risk factors.
Chest X-ray
A chest X-ray can confirm the presence and location of lung infection and helps distinguish pneumonia from other conditions.
Identifying the Cause
Blood tests, sputum tests, or other samples may help identify whether the cause is bacterial, viral, or another organism, guiding treatment.
Laboratory Tests
Chest X-ray
Confirms the presence, location, and extent of lung infection.
Complete Blood Count (CBC)
Helps identify signs of infection and assess its severity.
Sputum Culture
Can identify the specific bacteria causing pneumonia, when bacterial infection is suspected.
Pulse Oximetry
Measures blood oxygen levels and helps determine how severely the infection is affecting breathing.
Treatment
Antibiotics
Used for bacterial pneumonia. Antibiotics have no effect on viral pneumonia, making accurate diagnosis important.
Supportive Care
Fluids, rest, and fever management support recovery for both bacterial and viral pneumonia. Oxygen therapy may be needed in more severe cases.
Prevention
Get recommended vaccines
Vaccines against some of the bacteria and viruses that cause pneumonia, including pneumococcal and influenza vaccines, significantly reduce risk.
Practise good hand hygiene
Regular handwashing reduces the spread of many germs that can lead to pneumonia.
Avoid smoking
Smoking damages the lungs’ natural defences and significantly increases the risk of pneumonia.
Manage chronic health conditions
Conditions such as diabetes or heart disease increase the risk of pneumonia and its complications, so ongoing management matters.
Risk Factors
High Risk
These individuals are more likely to develop severe pneumonia.
- Adults over 65
- Infants and young children
- People with weakened immune systems
Increased Risk
These groups have a higher chance of developing pneumonia.
- People with chronic lung or heart conditions
- People who smoke
- People recently hospitalised or on a ventilator
Exposure Factors
Situations that increase the risk of developing pneumonia.
- Recent viral respiratory infection
- Exposure to air pollution or occupational irritants
- Limited access to vaccination
Complications
Pleural Effusion
Fluid can build up around the lungs, sometimes requiring drainage.
Bacteremia
The infection can spread into the bloodstream, becoming a more widespread and serious illness.
Respiratory Failure
Severe pneumonia can prevent the lungs from supplying enough oxygen to the body, requiring intensive care.
When to Seek Medical Care
Severe Difficulty Breathing
Rapid, laboured, or painful breathing requires immediate medical care.
Confusion
New confusion, particularly in older adults, is a medical emergency.
Bluish Lips or Face
Indicates low blood oxygen and requires emergency care.
High Fever Not Improving
A fever that persists or worsens despite treatment should be reassessed by a healthcare provider.
Prognosis
Good with Appropriate Treatment
Most people recover fully from pneumonia within one to three weeks with appropriate treatment.
More Serious in Certain Groups
Older adults, young children, and people with weakened immune systems face a higher risk of severe illness and complications.
Recovery Time Varies by Cause
Bacterial pneumonia often improves within days of starting antibiotics, while viral pneumonia may take longer to resolve.
Differential Diagnosis
Tuberculosis
Tuberculosis shares several respiratory symptoms with pneumonia, including cough, fever, and chest findings, but typically develops more gradually.
Sepsis
Severe pneumonia can itself trigger sepsis, and the two conditions can be difficult to distinguish in advanced cases.
Bronchitis
Bronchitis causes cough and chest discomfort but does not typically show the lung infiltrates seen on a chest X-ray in pneumonia.
References
World Health Organization (WHO)
World Health Organization guidance on pneumonia epidemiology, prevention, and global impact.
Centers for Disease Control and Prevention (CDC)
Clinical and public health guidance on pneumonia causes, diagnosis, treatment, and prevention.
American Thoracic Society (ATS) / IDSA Clinical Practice Guideline
Clinical practice guidelines for the diagnosis and management of community-acquired pneumonia.
Frequently Asked Questions
Is pneumonia contagious?
It depends on the cause. Pneumonia caused by viruses or certain bacteria can spread through respiratory droplets, while pneumonia arising from other causes may not be contagious at all.
Can pneumonia be cured?
Yes, in most cases. Bacterial pneumonia responds well to antibiotics, and viral pneumonia usually resolves with supportive care and time.
Do I need antibiotics for pneumonia?
Only if the cause is bacterial. Antibiotics do not work against viral pneumonia, so identifying the likely cause matters for treatment.
Can pneumonia be prevented?
Yes, to a significant extent. Vaccines against pneumococcal disease and influenza, good hand hygiene, and avoiding smoking all reduce risk.