Pneumonia is an infection or inflammation of the lung tissue. It may be caused by bacteria, viruses, fungi or other organisms. Severity ranges from mild illness treated at home to life-threatening infection requiring hospitalization.
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BIMARIDUR HEALTH ENCYCLOPEDIA
Pneumonia
Pneumonia is an acute infection of the lungs in which the air sacs (alveoli) become inflamed and may fill with fluid or pus, making breathing difficult.
ICDJ18.9
Affected areaLungs, particularly the air sacs (alveoli) and surrounding lung tissue.
ContagiousnessSome infections that cause pneumonia can spread between people through respiratory droplets, aerosols or contact, while other causes are not spread person-to-person.
01 • QUICK UNDERSTANDING
What is Pneumonia?
02 • BODY & MECHANISM
What happens in the body?
Body structure involved
The lungs contain branching airways ending in microscopic alveoli where oxygen and carbon dioxide are exchanged with the blood.
How it starts
Pneumonia develops when infectious organisms reach the lower respiratory tract and overcome normal lung defenses, causing inflammation and impaired gas exchange.
What happens inside the body
In pneumonia, infection triggers inflammation in the lung tissue. The alveoli may fill with inflammatory fluid or pus, reducing normal oxygen exchange.
03 • TYPES & CLASSIFICATION
Types and classification
Pneumonia can be classified by cause, clinical setting and affected location. Important clinical categories include community-acquired pneumonia, hospital-acquired pneumonia and ventilator-associated pneumonia.
Common categories include bacterial, viral and fungal pneumonia, as well as community-acquired, hospital-acquired and ventilator-associated pneumonia.
04 • SYMPTOMS
Symptoms and warning signs
Fever or chills
Difficulty breathing or shortness of breath
Chest pain or discomfort, especially with breathing or coughing
Fatigue or weakness
Sputum or phlegm production
Confusion, particularly in older adults
Nausea, vomiting or reduced appetite
06 • CAUSES
What can cause this disease?
Pneumonia can be caused by bacteria, viruses, fungi and, less commonly, other infectious organisms. Aspiration of food, liquid or stomach contents can also contribute.
07 • RISK FACTORS
Who may have a higher risk?
1
Very young age or older age
2
Chronic lung or heart disease
3
Diabetes and other chronic medical conditions
4
Smoking or exposure to tobacco smoke
5
Weakened immune system
6
Recent hospitalization or mechanical ventilation
7
Difficulty swallowing or aspiration risk
08 • DIAGNOSIS
How is Pneumonia diagnosed?
Evaluation may include medical history, examination, oxygen saturation measurement and chest imaging. Blood tests, sputum testing and other microbiological tests may be used when clinically appropriate.
Clinical evaluation
Fever
Rapid breathing
Low oxygen saturation
Abnormal lung sounds
Increased work of breathing
Fast heart rate
Confusion or reduced alertness
Laboratory tests
Complete blood count
Blood cultures when indicated
Sputum testing when clinically appropriate
Blood chemistry and kidney function
Inflammatory markers when clinically useful
Blood gas testing in selected severe cases
Targeted viral or bacterial testing
Imaging and scans
Chest X-ray
Chest CT in selected cases
Lung ultrasound in appropriate clinical settings
Special or confirmatory tests
Pulse oximetry
Arterial blood gas in selected severe cases
Respiratory pathogen testing
Bronchoscopy in selected complicated or unclear cases
Swallowing assessment when aspiration is suspected
09 • DIFFERENTIAL CONTEXT
Conditions that may look similar
Acute bronchitis
Influenza or other viral respiratory infection
COVID-19
Pulmonary embolism
Heart failure with pulmonary edema
Tuberculosis
Asthma or chronic obstructive pulmonary disease exacerbation
10 • EXTENT / STAGE
Stages or severity
Pneumonia is not usually staged like cancer. Clinicians assess severity according to symptoms, oxygenation, vital signs, imaging, complications and the person's underlying health.
Important:
Staging or grading systems differ between diseases. The information here is educational and should be interpreted by a qualified healthcare professional in the context of the individual case.
11 • TREATMENT
How is Pneumonia treated?
Treatment depends on the cause and severity. Bacterial pneumonia may require antibiotics, while viral or fungal causes require cause-specific management. Oxygen and hospital-based supportive care may be needed for severe disease.
Medicines that may be used
Antibiotics for appropriate bacterial pneumonia
Antiviral treatment for selected viral infections when indicated
Antifungal treatment for selected fungal infections
Fever and pain medicines when appropriate
Oxygen therapy for hypoxemia
Other supportive medicines based on the cause and complications
Medicine safety:
Medicines listed here are for educational information only. Do not start, stop, or change a medicine without professional medical advice.
12 • COMPLICATIONS
Possible complications
Complications may include low blood oxygen, respiratory failure, sepsis, pleural effusion, empyema, lung abscess and worsening of underlying heart or lung disease.
URGENT SAFETY INFORMATION
When should urgent medical help be considered?
Severe difficulty breathing
Blue or grey lips, face or skin
Very low oxygen saturation when measured
New confusion or difficulty staying awake
Severe chest pain
Rapid deterioration or signs of sepsis
If symptoms are severe, rapidly worsening, or life-threatening, seek emergency medical care immediately.
13 • OUTLOOK
Prognosis and recovery outlook
Prognosis depends on the organism, severity, age, underlying conditions and speed of appropriate treatment. Most mild cases recover, while severe pneumonia can be life-threatening.
How to interpret these statistics
Survival statistics describe outcomes in groups of people and cannot predict exactly what will happen to one individual. Prognosis depends on factors such as cancer stage, tumor biology, treatment response, overall health, and follow-up.
14 • EPIDEMIOLOGY
How common is it?
Pneumonia occurs worldwide and affects people of all ages. The greatest risks of severe disease are seen in young children, older adults and people with chronic illness or impaired immunity.
15 • PREVENTION
Risk reduction and prevention
Vaccination against relevant respiratory pathogens, hand hygiene, respiratory etiquette, avoiding tobacco smoke and controlling chronic diseases can help reduce risk.
16 • PREPARE FOR YOUR VISIT
Questions you may ask your doctor
1
What is the likely cause of my pneumonia?
2
Do I need a chest X-ray or other imaging?
3
Do I need antibiotics or another cause-specific treatment?
4
Can I safely recover at home?
5
What oxygen level should concern me?
6
What symptoms mean I should return urgently?
7
Do I need testing for a specific respiratory infection?
8
When can I safely return to normal activity?
Important medical information
BimariDur provides educational health information to help people understand diseases, symptoms, tests, and treatment concepts. It does not replace examination, diagnosis, or treatment by a qualified healthcare professional.
Do not delay professional medical care because of information read on BimariDur.