Pneumonia is a lung infection that can be caused by bacteria, viruses, fungi and, less commonly, other organisms. It can range from a mild illness to a serious condition requiring hospital treatment. The symptoms and severity can vary according to the germ involved, age, underlying health conditions and other risk factors.

What Is Pneumonia?

Pneumonia causes inflammation in the lungs and can make the air sacs, or alveoli, fill with fluid or pus. This can interfere with normal oxygen exchange and cause cough, fever, breathing difficulty and chest discomfort. Not every person with pneumonia has the same symptoms, and some older adults or people with serious medical conditions may have less typical signs.

Common Pneumonia Symptoms

The most common symptoms can include:

• Cough: A cough may occur with or without mucus.
• Fever or chills: Fever and chills can occur, although older adults may sometimes have a lower-than-normal temperature.
• Shortness of breath: Breathing may feel difficult or uncomfortable, particularly when the infection is more significant.
• Chest pain: Pain may become worse when taking a deep breath or coughing.
• Fatigue: Marked tiredness or weakness can accompany pneumonia.
• Confusion: Older adults may develop sudden confusion or changes in awareness.
• Other symptoms: Headache, muscle aches, nausea, vomiting or diarrhea may also occur.

What Causes Pneumonia?

Pneumonia can have several infectious causes. Bacteria and viruses are common causes, while fungal infections are less common. The specific cause is not always identified, especially in community-acquired pneumonia. The likely cause can influence testing and treatment.

Who Is at Higher Risk of Serious Pneumonia?

Pneumonia can affect people of any age, but the risk of serious illness is higher in certain groups. These include older adults, young children and people with chronic medical conditions or weakened immune systems. Smoking and other factors that affect lung health can also increase risk.

How Is Pneumonia Diagnosed?

A healthcare professional usually starts with your symptoms, medical history and a physical examination. The clinician may listen to your lungs and assess vital signs and oxygen levels. Depending on the situation, additional tests may be recommended.

Chest X-ray

A chest X-ray is commonly used to look for changes in the lungs that support a diagnosis of pneumonia. It can also help assess how much of the lung may be affected.

Pulse Oximetry

A pulse oximeter placed on a finger or another suitable site estimates blood oxygen saturation. Low oxygen levels can be a sign that pneumonia is affecting oxygen exchange and may help determine how closely a person needs to be monitored.

Blood Tests

Blood tests may be used to look for evidence of infection or inflammation and to assess overall health. In more serious cases, additional blood testing may be needed.

Sputum, Culture and Molecular Tests

For some patients, particularly those who are seriously ill or hospitalized, testing respiratory secretions, blood or other samples may help identify the organism causing the infection. These tests are not required for every mild case.

CT Scan

A chest CT provides more detailed images than a standard X-ray and may be considered when the diagnosis is unclear, symptoms are severe, complications are suspected or the clinical course is not as expected.

Pneumonia Treatment

Treatment depends on the cause, severity and the person's overall health. There is no single medicine that treats every type of pneumonia.

• Bacterial pneumonia: Antibiotics may be prescribed when bacterial infection is suspected or confirmed.
• Viral pneumonia: Some viral infections have specific antiviral treatments, but antiviral medicines do not work against every virus.
• Fungal pneumonia: Antifungal medicines may be required when a fungal infection is responsible.
• Supportive care: Fluids, rest and appropriate symptom-relief measures may be recommended.
• Oxygen therapy: People with low oxygen levels may need supplemental oxygen.
• Hospital care: Severe pneumonia may require intravenous medicines, oxygen support and close monitoring. Very severe cases may require intensive care or ventilatory support.

Do not start, stop or change antibiotics without medical advice. Antibiotics do not treat viral pneumonia, and inappropriate antibiotic use can cause side effects and contribute to antibiotic resistance.

When Does Pneumonia Need Urgent Medical Attention?

Seek urgent medical evaluation if pneumonia symptoms are accompanied by significant breathing difficulty, bluish or grey lips or skin, severe chest pain, new confusion, fainting, very low oxygen readings, rapidly worsening symptoms or an inability to keep fluids down. People at higher risk of complications should seek medical advice sooner rather than waiting for symptoms to become severe.

Pneumonia Recovery

Recovery time varies. Some people improve within a couple of weeks, while fatigue, cough or reduced exercise tolerance can persist for longer. Follow the prescribed treatment plan, stay adequately hydrated when medically appropriate, avoid smoking and gradually return to normal activity according to your clinician's advice.

Can Pneumonia Be Prevented?

Risk can be reduced through recommended vaccinations, hand hygiene, avoiding tobacco smoke, managing chronic health conditions and following appropriate infection-prevention measures. Vaccination recommendations vary by age and individual risk, so discuss the appropriate vaccines with a healthcare professional.

Pneumonia vs a Common Cold or Flu

Pneumonia can resemble other respiratory infections, particularly early in the illness. Persistent or worsening cough, breathing difficulty, chest pain, fever, low oxygen or significant weakness should not be assumed to be a routine cold. A clinical assessment can help determine whether further testing is needed.

Key Takeaways

• Pneumonia is an infection of the lungs caused by different types of germs.
• Common symptoms include cough, fever or chills, shortness of breath and chest pain with breathing or coughing.
• Diagnosis may involve examination, chest X-ray and oxygen measurement, with additional tests for selected patients.
• Treatment depends on the cause and severity; antibiotics are used for bacterial infections, not viral infections.
• Severe breathing difficulty, confusion, bluish skin or rapidly worsening symptoms require urgent medical assessment.

Frequently Asked Questions About Pneumonia