Pneumonia
Pneumonia is an acute inflammation of the tissues of one or both lungs, caused in most cases by a viral or bacterial infection, but sometimes also by fungi or by the inhalation of substances or foreign bodies. This condition leads to an accumulation of fluid or pus in the pulmonary alveoli — the small air sacs at the end of the bronchi — hindering the proper exchange of oxygen and carbon dioxide and making breathing difficult.
Looking for Pneumonia Care?
Related services:
Services for the diagnosis and treatment of Pneumonia are available at:
On this page
- What Is Pneumonia?
- What Are the Symptoms of Pneumonia?
- How Do You Diagnose Pneumonia?
- How Do You Treat Pneumonia?
- How Can Pneumonia Be Prevented?
What Is Pneumonia?
Pneumonia is a respiratory disease that affects lung tissue, causing inflammation and a reduction in respiratory function.
The bronchi, which carry inhaled air to the lungs, end in pulmonary alveoli — tiny structures where the exchange of oxygen and carbon dioxide takes place.
When pneumonia develops, the alveoli fill with fluid or pus, preventing the blood from becoming properly oxygenated.
The inflammation may involve:
- A single lobe of the lung (lobar pneumonia).
- Multiple areas at the same time (multilobar pneumonia).
- Or it may also extend to the bronchi, resulting in bronchopneumonia.
Pneumonia remains one of the leading causes of hospitalization and mortality, especially among vulnerable or immunocompromised individuals.
Who Is Most at Risk for Pneumonia?
Some people are more vulnerable to developing pneumonia or to more severe forms of the disease, including:
- Elderly individuals (especially those over 65 years old).
- Newborns and young children — it is the leading cause of death from infectious disease in children worldwide (source: WHO).
- Smokers.
- People with chronic conditions (asthma, chronic obstructive pulmonary disease – COPD, cystic fibrosis, heart, kidney, or liver diseases).
- Immunocompromised patients, such as those with HIV infection, AIDS, undergoing chemotherapy, or receiving immunosuppressive therapy following a transplant.
What Are the Symptoms of Pneumonia?
The symptoms of pneumonia can vary depending on the cause of the infection, the patient’s age, and their overall health condition.
In many cases, symptoms develop over a few days, but they may also appear suddenly, with a rapid worsening of respiratory function.
The most common symptoms include:
- Shortness of breath and difficulty breathing.
- Chest pain, which may worsen when breathing or coughing.
- Fever, often accompanied by chills or heavy sweating.
- Dry or productive cough, with thick sputum that may sometimes be streaked with blood (hemoptysis).
- Muscle aches and marked fatigue.
- Loss of appetite and general malaise.
- Abnormal breathing sounds (detectable during a medical exam) and rapid heartbeat (tachycardia).
Pneumonia is more common during the colder months, when viral respiratory infections are widespread and can lead to bacterial complications.
Symptoms may appear milder in elderly or immunocompromised individuals, where the only signs may be fatigue, confusion, or loss of mental clarity.
If one or more of these symptoms occur, it is important to contact a primary care physician. However, if severe signs such as significant breathing difficulty, intense chest pain, confusion, or a bluish discoloration of the lips and nails (cyanosis) appear, emergency care should be sought immediately.
How Do You Diagnose Pneumonia?
The diagnosis of pneumonia begins with a thorough medical examination, during which a general practitioner or specialist evaluates the patient’s symptoms and overall condition.
During the physical exam, the doctor:
- Listens to the chest during deep breathing to check for abnormal sounds, which may indicate fluid or inflammation in the lungs.
- Checks heart rate and breathing rate.
- Gathers detailed information about the onset and progression of symptoms.
- Performs a full physical examination to detect any signs of infection or respiratory difficulty.
Because pneumonia symptoms can resemble those of other respiratory conditions — such as asthma, the common cold, or bronchitis — the doctor may order additional diagnostic tests to confirm the diagnosis and identify the exact cause.
These may include:
- Blood tests, to check for signs of infection and elevated white blood cell count.
- Microbiological analysis of sputum, useful for identifying the bacteria or virus responsible.
- Chest X-ray, which allows visualization of areas of inflammation or fluid buildup in the lungs.
- Chest CT scan, recommended in more complex cases for a detailed assessment of lung tissue.
- Flexible bronchoscopy, which enables the collection of mucus or tissue samples for more in-depth analysis.
How Do You Treat Pneumonia?
The treatment of pneumonia depends on the cause of the infection (bacterial, viral, or fungal), the severity of symptoms, and the patient’s overall health.
Mild cases of pneumonia can be managed at home under the supervision of a primary care physician, while more severe or complicated cases require hospitalization, especially for the elderly, young children, or people with chronic conditions or weakened immune systems.
Bacterial Pneumonia
Bacterial pneumonia is treated with targeted antibiotics, prescribed by the doctor based on the type of bacteria responsible.
During treatment, it is important to:
- Take medications correctly for the entire prescribed duration.
- Maintain proper hydration.
- Get adequate rest.
- Follow medical instructions and monitor symptom progression.
In cases where the infection is acquired in a hospital (nosocomial pneumonia), specific antibiotics may be necessary for more resistant bacteria. Recovery is generally complete, although residual coughing may persist for several weeks.
Viral or Fungal Pneumonia
When the cause is viral, the doctor may prescribe antiviral medications or supportive treatments.
Fungal pneumonia, which is rarer, requires specific antifungal therapies.
Other Supportive Treatments
In some cases, additional treatments may include:
- Corticosteroids, to reduce inflammation and enhance the effectiveness of antibiotics.
- Oxygen therapy, useful for patients with respiratory insufficiency, adjusted according to the severity of the condition.
For highly contagious pneumonia or cases caused by highly transmissible viruses, such as interstitial pneumonia from COVID-19, hospitalization in isolation is required to prevent the spread of infection.
Possible Complications of Pneumonia
In some cases — especially in young children, the elderly, or people with chronic conditions such as diabetes, heart disease, or immunodeficiency — pneumonia can lead to serious complications that require prompt treatment.
The main complications of pneumonia include:
- Septicemia (sepsis): occurs when bacteria from the lung infection enter the bloodstream, spreading throughout the body and triggering a potentially life-threatening inflammatory response.
- Pleurisy: inflammation of the pleura, the thin membrane lining the lungs and chest cavity. It can cause severe chest pain and, in more serious cases, fluid accumulation or respiratory failure.
- Lung abscess: formation of a pus-filled cavity in lung tissue, a rare but serious complication that can occur in patients with severe preexisting conditions or chronic alcohol abuse.
How Can Pneumonia Be Prevented?
Pneumonia can be prevented by adopting proper behaviors and effective preventive measures.
Although bacterial pneumonia itself is not contagious, some viruses and bacteria that cause it can be transmitted from person to person.
To reduce the risk, it is important to:
- Dispose of used tissues immediately, as germs can survive on surfaces for several hours.
- Wash hands frequently and thoroughly, especially after coughing, sneezing, or touching common surfaces.
- Cover the mouth and nose with a tissue or bent elbow when coughing or sneezing, to prevent the spread of respiratory droplets.
A healthy lifestyle is another key pillar of prevention:
- Avoid smoking and alcohol abuse, which damage the lungs and reduce their ability to fight infections.
- Maintain a balanced diet, engage in regular physical activity, and ensure quality sleep to support the immune system.
Vaccinations play a key role in preventing more severe forms of pneumonia:
- Pneumococcal vaccine, recommended for children, the elderly, and people with chronic illnesses.
- Influenza vaccine, helpful in reducing respiratory complications related to the flu virus.
- Anti-SARS-CoV-2 vaccine, to prevent interstitial pneumonia associated with COVID-19.
Reviewed November 2025.