Pneumonia: everything you need to know about causes, symptoms and treatment

Introduction

Pneumonia is an acute infection of the lungs that causes inflammation and filling of the alveoli, the small cavities where gas exchange between air and blood occurs. Pneumonia can affect one or more lung lobes or spread diffusely throughout the lungs. It can be caused by bacteria, viruses, fungi, or other microorganisms. Pneumonia is a common and potentially serious illness, especially in elderly individuals, children, immunocompromised individuals, or those with chronic respiratory or cardiac diseases.

Pneumonia presents symptoms such as cough, fever, chills, difficulty breathing, chest pain, or fatigue. Diagnosis is based on clinical examination, chest X-ray, blood tests, and sputum or blood sampling to identify the responsible agent. Treatment depends on the type of pneumonia and its severity. It may include antibiotics, antivirals, antifungals, antipyretics, cough suppressants, bronchial fluidizers, oxygen therapy, or in severe cases, assisted ventilation. Prevention of pneumonia involves vaccination, hand hygiene, mask-wearing, avoiding smoking, and strengthening the immune system. In this article, we will explain everything you need to know about pneumonia: its causes, symptoms, diagnosis, treatment, and potential complications. We will also provide tips for preventing pneumonia.

Types of Pneumonia

Pneumonia can be classified according to various criteria, such as the place of acquisition, the responsible agent, the affected lung area, or the severity level. Here are the main types of pneumonia that you should know about:

Community-Acquired Pneumonia

This is the most common form of pneumonia. It is contracted outside the hospital or within 48 hours of admission. It can be caused by bacteria, viruses, fungi, or parasites. The most common agents are pneumococcus, mycoplasma, influenza virus, and respiratory syncytial virus. Community-acquired pneumonia presents with high fever, productive cough, chest pain, and respiratory distress. Treatment involves antibiotics, antivirals, or antifungals, depending on the causative agent.

Hospital-Acquired Pneumonia (Nosocomial)

This is a pneumonia that occurs during a hospital stay, either after 48 hours of admission or within 14 days following discharge. It is often more severe than community-acquired pneumonia because it is caused by germs that are more resistant to antibiotics. The most common agents are Staphylococcus aureus, Pseudomonas, Acinetobacter, and Klebsiella. Nosocomial pneumonia presents with persistent fever, purulent cough, respiratory distress, and overall deterioration of health. Treatment involves broad-spectrum antibiotics tailored to the identified germ.

Aspiration Pneumonia

Aspiration pneumonia results from inhaling foreign substances into the lungs, such as food, liquids, vomit, or oral secretions. It can occur in individuals with swallowing, coughing, or consciousness disorders. It can be caused by anaerobic bacteria such as Fusobacterium, Peptostreptococcus, or Bacteroides. Aspiration pneumonia presents with fever, foul-smelling cough, bad breath, and respiratory distress. Treatment involves antibiotics that are effective against anaerobic bacteria, such as metronidazole or clindamycin.

Opportunistic Pathogen Pneumonia

This type of pneumonia affects individuals with weakened immune systems, such as AIDS patients, transplant recipients, cancer patients, or those taking corticosteroids. It is caused by pathogens that are not usually pathogenic but take advantage of the weakened defenses of the body to cause an infection. The most common agents are Pneumocystis jirovecii, cytomegalovirus, Cryptococcus, or Aspergillus. Opportunistic pathogen pneumonia presents with fever, dry cough, dyspnea, and hypoxemia. Treatment involves specific medications such as co-trimoxazole, ganciclovir, amphotericin B, or voriconazole.

Causes of Pneumonia

Pneumonia is a lung infection that can have various causes. Depending on the type of infectious agent, pneumonia can be more or less severe and require appropriate treatment. Here are the main causes of pneumonia:

Bacterial Infections

Bacteria are the most common causes of pneumonia in adults. They can be transmitted through the air, by contact with sick individuals, or through contaminated objects. The most common bacterium is Streptococcus pneumoniae, which causes community-acquired pneumonia. Other bacteria such as Staphylococcus aureus, Pseudomonas, or Klebsiella can be responsible for hospital-acquired pneumonia. Some bacteria like Legionella, Mycoplasma, or Chlamydia can also cause atypical pneumonia, characterized by less severe symptoms and a slower progression.

Viruses and Fungi

Viruses are the most common causes of pneumonia in children. They can be transmitted through coughing, sneezing, or nasal secretions. The most common viruses are respiratory syncytial virus, influenza virus, parainfluenza virus, and rhinovirus. Viral pneumonias are often less severe than bacterial pneumonias, but they can be complicated by bacterial superinfection. Some viruses, such as SARS-CoV-2 or SARS virus, can cause severe pneumonia.

Fungi are rare causes of pneumonia, mainly affecting individuals with weakened immune systems such as AIDS patients, transplant recipients, cancer patients, or those taking corticosteroids. The most common fungi are Pneumocystis jirovecii, cytomegalovirus, Cryptococcus, or Aspergillus. Fungal pneumonia is difficult to diagnose and treat, and it can lead to serious complications.

Factors Contributing to Pneumonia

Pneumonia can affect anyone, but some people are more likely to develop it than others. There are factors that increase the risk of contracting pneumonia, either by facilitating the entry of germs into the lungs or by weakening the body’s defenses. Here are the main factors contributing to pneumonia:

Age

Children and elderly individuals are more vulnerable to pneumonia. Infants have an immature immune system and narrow airways, making them more susceptible to infections. People over 65 often experience decreased immunity, reduced coughing and bronchial secretions, as well as associated chronic conditions such as diabetes or heart failure. After 65 years of age, pneumonia becomes three to six times more common.

Pre-existing Lung Disease

Individuals with chronic respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, or cystic fibrosis are more prone to pneumonia. These conditions impair lung function, promote secretion stagnation, and reduce resistance to infections. Smoking and exposure to secondhand smoke are also risk factors as they irritate the respiratory tract and impair the defense mechanism of bronchial cilia.

Hospitalization

Hospitalized individuals, especially those in intensive care units or on respiratory support, may develop nosocomial pneumonia, meaning pneumonia acquired in the hospital setting. These pneumonias are often more severe than community-acquired pneumonia because they are caused by germs that are more resistant to antibiotics. The most common agents are Staphylococcus aureus, Pseudomonas, Acinetobacter, and Klebsiella.

Immune Deficiency

Individuals with weakened immune systems due to various conditions such as HIV, AIDS, cancer, organ transplantation, or corticosteroid use are more susceptible to opportunistic pneumonias. These pneumonias are caused by pathogens that are not usually pathogenic but take advantage of the weakened defenses of the body to cause an infection. The most common agents are Pneumocystis jirovecii, cytomegalovirus, Cryptococcus, or Aspergillus.

Pneumonia Symptoms

Pneumonia is a lung infection that can have serious consequences if not treated promptly. It is therefore important to recognize the symptoms of pneumonia and consult a doctor as soon as possible. Here are the main signs that should alert you:

Common Symptoms

Pneumonia symptoms can vary depending on the type of pneumonia, the causative agent, the age, and the overall health of the affected individual. However, the most common symptoms are:

• Severe cough, with or without sputum (mucus or pus);
• Fever, often high, accompanied by chills;
• Difficulty breathing or shortness of breath;
• Chest pain that worsens with deep breathing or coughing;
• Fatigue, general discomfort, loss of appetite;
• Nausea, vomiting, diarrhea (more common in children).

These symptoms can appear suddenly or gradually. They can be more or less severe depending on the severity of the pneumonia.

When to Consult a Doctor

It is recommended to consult a doctor as soon as the first symptoms of pneumonia appear, especially if you are in the high-risk groups such as children, elderly individuals, immunocompromised individuals, or those with chronic illnesses. The diagnosis of pneumonia is based on a clinical examination, chest X-ray, blood tests, and sputum sample collection to identify the causative agent.

You should seek emergency medical attention if you experience signs of respiratory distress, such as rapid, shallow, or wheezing breathing, cyanosis (bluish coloration of the skin or lips), confusion, or drowsiness. These signs indicate that pneumonia is severe and requires hospitalization and oxygen therapy.

Diagnostic of Pneumonia

The diagnosis of pneumonia is based on evaluating symptoms, physical examination, and additional tests. These tests confirm the presence of a lung infection, identify the causative agent, assess the severity of pneumonia, and detect possible complications. Here are the main tests used for diagnosing pneumonia:

Medical Examinations

Medical examinations include:

• Auscultation of the lungs with a stethoscope: The doctor listens to the respiratory sounds in search of crackles, wheezing, or decreased breath sounds, which are signs of inflammation or congestion in the lungs;
• Chest X-ray: This is the gold standard test to confirm the diagnosis of pneumonia. It allows visualization of the infectious focus, its location, extent, and density. It can also reveal complications such as pleural effusion, abscess, or cavitation;
• Pleuro-pulmonary ultrasound: This is an examination performed using an ultrasound probe applied to the lungs. It allows visualization of an infectious focus or effusion. The advantage is that this examination is quick, simple, can be done at the patient’s home, and is non-irradiating;
• CT scan of the chest: This is a more precise examination than X-ray, which allows better definition of the infectious focus and detection of more subtle abnormalities. It is indicated in cases of diagnostic uncertainty, atypical pneumonia, severe pneumonia, or suspicion of complications;
• Blood tests: They can show an increase in white blood cells (leukocytosis), which indicates an inflammatory reaction, an increase in neutrophils, which are cells involved in defense against bacteria, and an increase in C-reactive protein (CRP), an inflammation marker;
• Sputum culture: This is a microbiological analysis that identifies the causative agent of pneumonia by culturing germs present in bronchial secretions. It helps in choosing the most appropriate antibiotic for the causative organism.

Interpretation of Results

The interpretation of medical test results allows for the diagnosis of pneumonia, determination of its type, cause, and severity, and selection of the most appropriate treatment. The physician relies on the following criteria:

• The presence of an infectious focus on chest X-ray, which can be unilateral or bilateral, segmental or lobar, alveolar or interstitial;
• The nature of the causative agent, which can be bacterial, viral, fungal, or parasitic, based on sputum or blood sample results;
• The severity of pneumonia, which can be assessed using clinical scores such as the CURB-65 score or PSI score, taking into account parameters like age, respiratory rate, blood pressure, mental confusion, blood urea, and oxygen saturation. These scores help define the severity level of pneumonia and determine the level of care needed (outpatient, conventional hospitalization, or intensive care);
• The presence of complications, such as pleural effusion, abscess, cavitation, acute respiratory distress, or sepsis, which can be detected by chest X-ray, pleuro-pulmonary ultrasound, or CT scan.

Prevention of Pneumonia

Pneumonia is a serious lung infection that can lead to complications and death. Therefore, it is essential to prevent pneumonia as much as possible by adopting individual and collective protective measures. Here are the main ways to prevent pneumonia:

Vaccines

Vaccination is an effective means of preventing pneumonia caused by certain infectious agents. There are vaccines available against the most common bacteria, such as pneumococcus and Haemophilus influenzae type B (Hib), as well as against the influenza and COVID-19 viruses. These vaccines are recommended for individuals at risk of pneumonia, such as children, elderly individuals, immunocompromised individuals, or those with chronic illnesses. It is important to adhere to the vaccination schedule and get vaccinated annually against influenza and COVID-19, as these viruses can evolve and may require booster shots.

Tips to reduce the risk

In addition to vaccination, there are simple daily habits you can adopt to reduce your risk of pneumonia, especially during the winter. Here are some tips:

• Stop smoking, as tobacco smoke reduces your body’s ability to fight infections. Also, avoid exposure to secondhand smoke;
• Wash your hands regularly with soap and water, or with an alcohol-based solution. Hands are constantly in contact with microbes that can cause various infections, including pneumonia. These microbes enter the body when you touch your eyes, nose, or mouth;
• Cover your nose and mouth when coughing or sneezing, with a tissue or the crook of your elbow. Dispose of your tissues after use. Do not share your glass or utensils with a sick person;
• Wear a mask when in contact with sick people or when visiting public places. The mask can protect you from respiratory droplets containing germs;
• Maintain a balanced diet rich in fruits and vegetables, which provide vitamins and antioxidants. Drink enough water to stay hydrated and thin your bronchial secretions;
• Exercise regularly to strengthen your immune system and respiratory capacity. Avoid intense efforts if you are sick;
• Get enough sleep to allow your body to regenerate and fight infections. Avoid stress, which can weaken your natural defenses.

Treatment of pneumonia

The treatment of pneumonia aims to eliminate the infectious agent responsible for lung inflammation, relieve symptoms, and prevent complications. The choice of treatment depends on the type of pneumonia, its severity, the patient’s age, and health condition. Here are the main treatments used for pneumonia:

Antibiotics

Antibiotics are medications that kill or inhibit the growth of bacteria. They are the treatment of choice for bacterial pneumonia, which is most common in adults. Antibiotics should be taken as soon as possible, as prescribed by the doctor, and until the end of the treatment, even if symptoms improve. The type of antibiotic used depends on the suspected or identified bacteria and its sensitivity to different antibiotics. In general, the first-line treatment includes the use of amoxicillin, macrolides (erythromycin, clarithromycin, azithromycin), or fluoroquinolones (levofloxacin, moxifloxacin). In cases of severe pneumonia, allergy, or antibiotic resistance, other antibiotics may be used, such as cefotaxime, ceftriaxone, vancomycin, or linezolid.

Antivirals and Antifungals

Antivirals are medications that inhibit the replication of viruses. They are the treatment of choice for viral pneumonias, which are most common in children. Antivirals should be taken as soon as possible after the onset of symptoms and for the duration indicated by the doctor. The type of antiviral used depends on the virus involved. For example, oseltamivir or zanamivir is used to treat pneumonias caused by the influenza virus, while ganciclovir or foscarnet is used to treat pneumonias caused by cytomegalovirus.

Antifungals are medications that destroy or inhibit the growth of fungi. They are the treatment of choice for fungal pneumonias, which are rare and mainly affect immunocompromised individuals. Antifungals should be taken as prescribed by the doctor and for a prolonged period because fungi are difficult to eradicate. The type of antifungal used depends on the fungus involved. For example, cotrimoxazole is used to treat pneumonias caused by Pneumocystis jirovecii, while amphotericin B or voriconazole is used to treat pneumonias caused by Aspergillus.

Treating pneumonia at home or in the hospital

Most cases of pneumonia can be treated at home with oral medications and supportive measures such as rest, hydration, taking antipyretics to reduce fever, and avoiding tobacco and alcohol. It is important to follow the doctor’s recommendations and monitor the progression of symptoms. If symptoms worsen or persist, it is important to consult the doctor again.

In some cases, hospitalization may be necessary, especially if the pneumonia is severe, the patient is elderly, there are signs of respiratory distress, the patient has associated chronic diseases, or the patient does not respond to initial treatment. Hospitalization allows for intravenous medication administration, oxygen therapy, close monitoring, and, if necessary, assisted ventilation.

Potential complications of pneumonia

Pneumonia is a serious lung infection that can lead to complications if not treated correctly or promptly. These complications can endanger the patient’s life or impair their quality of life. Here are the main potential complications of pneumonia:

• Sepsis: This is the spread of the infection into the bloodstream, which can cause septic shock, a sudden drop in blood pressure, and organ failure. This complication is more common with pneumonia caused by pneumococcus, staphylococcus, or Legionella bacteria. It requires intensive care management and broad-spectrum antibiotic therapy;
• Respiratory difficulties: This refers to a decrease in lung oxygenation capacity, which can lead to hypoxia (low oxygen levels in the blood) or acute respiratory distress (severe respiratory failure). This complication can be due to extensive lung damage, bronchial obstruction by secretions, or right heart failure (cor pulmonale). It requires oxygen therapy or assisted ventilation;
• Pleural fluid accumulation: This is the presence of fluid accumulation in the pleura (the membrane between the lung and chest wall) or pleurisy (inflammation of the pleura). This complication can result from pleural irritation due to infection, heart failure, or autoimmune disease. It can cause chest pain, coughing, and respiratory discomfort. It requires pleural fluid drainage for fluid removal and analysis of its nature.

Conclusion

Pneumonia is a lung infection that can have varied causes, symptoms, and treatments. It can be mild or severe, depending on the type of pneumonia, the age, and the health status of the patient. It is important to recognize the signs of pneumonia and to consult a doctor as soon as possible to receive appropriate treatment and avoid complications. Here are the key points to remember about pneumonia:

Summary and Key Points to Remember

• Pneumonia is an infection of the lung alveoli, caused by bacteria, viruses, fungi, or other microorganisms;
• Pneumonia presents with symptoms such as cough, fever, difficulty breathing, chest pain, and fatigue;
• Diagnosis of pneumonia relies on clinical examination, chest X-ray, blood tests, and sputum analysis;
• Treatment of pneumonia depends on the type and severity and may include antibiotics, antivirals, antifungals, fever reducers, cough suppressants, bronchial expectorants, oxygen therapy, or assisted ventilation in severe cases;
• Prevention of pneumonia involves vaccination, hand hygiene, mask-wearing, smoking avoidance, and immune system strengthening;
• Pneumonia can lead to complications such as lung infection, sepsis, respiratory distress, or pleural effusion.

We hope this article has helped you better understand pneumonia, its causes, symptoms, diagnosis, treatment, and prevention. If you have any questions or comments, feel free to share them with us.