Pneumonia
Also called: Lung infection, Community-acquired pneumonia
Infection that inflames the air sacs of the lungs, which fill with fluid or pus. It causes cough, fever and breathlessness and can be serious in infants, older adults and people with other illnesses.
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What happens in the body
Microbes reach the alveoli, triggering an inflammatory exudate that consolidates part of the lung and impairs oxygen transfer.
Causes
- Streptococcus pneumoniae (most common bacterium)
- Haemophilus influenzae, Mycoplasma, Legionella, Staphylococcus aureus
- Viruses: influenza, RSV, SARS-CoV-2
- Aspiration of mouth or stomach contents
- Fungi in people with weak immunity
Risk factors
- Age under 5 or over 65
- Smoking
- COPD, heart failure, diabetes
- Weakened immunity
- Swallowing problems
- Recent viral infection
Symptoms
- Cough with coloured sputum
- Fever and chills
- Breathlessness and fast breathing
- Sharp chest pain on breathing
- Confusion in older people
Diagnosis — tests and examinations
- Chest examination and oxygen saturation
- Chest X-ray
- Blood tests (CRP, white cells), severity score (CURB-65)
- Sputum and blood cultures, urine antigen tests in severe cases
Treatment
Medicines and medical treatment
- Antibiotics chosen by severity and local guidelines (e.g. amoxicillin; add a macrolide for atypical cover)
- Antivirals for influenza or COVID-19 when indicated
- Oxygen, fluids and pain relief
Operations and procedures
- Drainage of an infected pleural effusion (empyema)
- Ventilation in intensive care for respiratory failure
Self-care, home remedies and lifestyle
- Rest and plenty of fluids
- Paracetamol for fever
- Complete the full antibiotic course
- Do not smoke
Possible complications
- Sepsis
- Pleural effusion and empyema
- Lung abscess
- Respiratory failure
Prevention
- Pneumococcal and influenza vaccines
- Stopping smoking
- Hand hygiene
Outlook
Most healthy adults recover within 2–4 weeks; mortality is higher in older and frail people.
When to see a doctor
Seek urgent care for breathlessness, chest pain, confusion, blue lips or high fever that does not settle.
Sources and further reading
These sources cover this condition. They have not been checked against every statement on this page.
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