Pneumonia: Causes, Symptoms, and Diagnosis

• Pneumonia is an inflammatory condition of the lung affecting primarily the small air sacs known as alveoli
• Pneumonia is typically caused by infection with viruses or bacteria and less commonly by other microorganisms, certain medications, and conditions.

Causes of Pneumonia

• Pneumonia can arise from a variety of infectious and non-infectious causes.
• Infectious agents include bacteria, viruses, fungi, and parasites.
• The most common cause of bacterial pneumonia is Streptococcus pneumoniae.
• Viral pneumonias are frequently caused by influenza viruses, respiratory syncytial virus (RSV), and adenoviruses.
• Fungal pneumonias are more common in individuals with weakened immune systems and can be caused by organisms such as Pneumocystis jirovecii, Aspergillus, and Histoplasma.
• Non-infectious causes include aspiration of food or liquids, inhalation of irritants, and certain medications.

Symptoms and Diagnosis

• Common symptoms include cough, chest pain, fever, and difficulty breathing.
• Other symptoms can include:
  • Production of sputum (phlegm).
  • Fatigue.
  • Loss of appetite.
  • Sweating and shivering.
  • Rapid breathing and heart rate.
  • Confusion, especially in older adults.
• Diagnosis typically involves a medical history, physical examination, and diagnostic tests.
• Chest X-rays are commonly used to visualize the lungs and identify areas of inflammation or infection.
• Blood tests can help identify the causative organism and assess the severity of the infection.
• Sputum tests may be performed to identify bacteria or fungi.
• Pulse oximetry is used to measure the oxygen saturation in the blood.
• In some cases, a CT scan of the chest or bronchoscopy may be necessary.

Risk Factors

• Age: Infants and young children, as well as older adults, are at higher risk
• Chronic diseases: Conditions such as asthma, chronic obstructive pulmonary disease (COPD), heart disease, diabetes, and weakened immune system increase the risk.
• Smoking: Damages the lungs' natural defenses against infection.
• Weakened immune system: Individuals with HIV/AIDS, organ transplant recipients, or those undergoing chemotherapy are more susceptible.
• Exposure to certain chemicals or pollutants: Can irritate the lungs and increase susceptibility.
• Difficulty swallowing: Conditions that impair swallowing, such as stroke or neurological disorders, increase the risk of aspiration pneumonia.
• Hospitalization: Especially with ventilator use, increases the risk of healthcare-associated pneumonia.

Causative Organisms

• Bacteria:
  • Streptococcus pneumoniae is the most common bacterial cause.
  • Other bacteria include Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, and Staphylococcus aureus.
• Viruses:
  • Influenza viruses (A and B).
  • Respiratory syncytial virus (RSV).
  • Adenoviruses.
  • Rhinovirus.
  • Coronavirus.
• Fungi:
  • Pneumocystis jirovecii (especially in immunocompromised individuals).
  • Aspergillus.
  • Histoplasma.
  • Coccidioides.
  • Candida.
• Other Organisms:
  • Parasites (rarely).
  • Aspiration of food, liquids, or gastric contents.

Treatment Options

• Treatment depends on the type and severity of the pneumonia, as well as the patient's overall health.
• Antibiotics are used to treat bacterial pneumonia.
• Antiviral medications may be used for viral pneumonia, particularly influenza.
• Antifungal medications are used for fungal pneumonia.
• Supportive care includes:
  • Oxygen therapy to improve oxygen levels in the blood.
  • Pain management with over-the-counter or prescription medications.
  • Fever control with antipyretics.
  • Adequate hydration and nutrition.
  • Rest to promote healing.
• Hospitalization may be necessary for severe cases, especially in older adults, infants, and individuals with underlying health conditions.
• In the hospital, treatment may include:
  • Intravenous antibiotics or antivirals.
  • Respiratory support such as mechanical ventilation.
  • Monitoring of vital signs and oxygen levels.
  • Management of complications such as sepsis or respiratory failure.

Prevention Strategies

• Vaccination:
  • Pneumococcal vaccines (PCV13 and PPSV23) can help prevent pneumococcal pneumonia.
  • Influenza vaccine is recommended annually to prevent influenza-related pneumonia.
  • Haemophilus influenzae type b (Hib) vaccine is recommended for children.
  • COVID-19 vaccines can help prevent pneumonia caused by the virus
• Good hygiene:
  • Frequent handwashing with soap and water.
  • Covering coughs and sneezes with a tissue or elbow.
  • Avoiding close contact with sick individuals.
• Smoking cessation:
  • Quitting smoking improves lung health and reduces the risk of pneumonia.
• Healthy lifestyle:
  • Maintaining a balanced diet.
  • Regular exercise.
  • Adequate sleep.
• Avoiding exposure to pollutants:
  • Minimizing exposure to air pollution, dust, and chemicals.
• Managing underlying conditions:
  • Controlling chronic diseases such as diabetes, heart disease, and lung disease.
  • Strengthening the immune system through proper nutrition and medical care.
• Preventing aspiration:
  • Proper positioning during feeding for infants and individuals with swallowing difficulties.
  • Avoiding excessive alcohol consumption, which can impair swallowing.