Pneumonia: Causes, Symptoms, Diagnosis, Treatment and Precautions

Blog written by: DHRITHI BHAT

Pneumonia is a lung infection that could affect only one or both the lungs of our body. It causes the air sacs, or alveoli, in the lungs to enlarge with fluid or pus. Pneumonia might arise from bacteria, viruses, or fungi. Mild to severe symptoms could include anything from a cough that generates sticky mucus to fever, chills, and trouble breathing. The severity of your pneumonia will depend on your age, general health, and the infection's origin.



There are several causes of pneumonia, which can be broadly classified into infectious and non-infectious factors.

Infectious Causes: The majority of pneumonia cases are caused by infectious agents, such as bacteria, viruses, fungi, and, less commonly, parasites.

  • Bacterial Pneumonia: The most typical bacterial cause of pneumonia is streptococcus pneumoniae, sometimes referred to as pneumococcus. Pneumonia can also be caused by other bacteria, such as Haemophilus influenzae and Staphylococcus aureus, especially in groups that are already at risk.
  • Viral Pneumonia: Influenza viruses, respiratory syncytial virus (RSV), and the SARS-CoV-2 virus responsible for COVID-19 can all cause viral pneumonia.
  • Fungal Pneumonia: Pneumocystis jirovecii infections, for instance, can harm those with compromised immune systems, such as those with HIV/AIDS.

Non-Infectious Causes: Pneumonia can also be triggered by non-infectious factors, including:

  • Aspiration: Inhaling food, liquids, or gastric contents into the lungs can lead to aspiration pneumonia.
  • Chemical Irritants: Inhalation of toxic substances, fumes, or harmful chemicals can cause chemical pneumonia.
  • Immunocompromised State: Due to illnesses like HIV/AIDS, cancer, or organ transplantation, people who have weaker immune systems are more vulnerable to opportunistic infections that can cause pneumonia.
  • Inhalation of Foreign Objects: In children, the accidental inhalation of small objects can lead to pneumonia.
  • Underlying Health Conditions: The risk of pneumonia can be affected by chronic conditions such as chronic obstructive pulmonary disease (COPD), asthma, and heart failure.



  • Cough: A chronic cough that occasionally coughs up phlegm or mucus is a common sign of pneumonia. The cough may start out dry before turning productive and producing green, yellow, or red sputum.
  • Fever: A high temperature, which may sometimes include chills and sweating, is a common sign of pneumonia. When there is bacterial pneumonia, the fever is typically more intense.
  • Difficulty Breathing: A defining sign of pneumonia is respiratory problems or shortness of breath. People occasionally experience the feeling of being out of breath, especially after engaging in strenuous activity.
  • Chest Pain: Pneumonia can cause chest pain, which is frequently described as a sharp, stabbing ache. Coughing or hard breathing may make this pain worse.
  • Fatigue: Extreme exhaustion and lethargy brought on by pneumonia may make regular activities difficult.
  • Rapid Breathing: A person with pneumonia may occasionally have a faster breathing rate. Shallow breaths may be present along with rapid breathing.
  • Confusion (especially in the elderly): Confusion or changes in mental awareness are more likely to occur in elderly people or people with compromised immune systems. This is a serious indication that requires quick medical care.
  • Nausea and Vomiting: Some pneumonia patients may develop gastrointestinal symptoms like nausea or vomiting.
  • Cyanosis: Due to low blood oxygen levels, lips and nails may take on a bluish tinge in severe cases of pneumonia.


Diagnostic process:

  • Medical History and Symptom Assessment: A thorough evaluation of the patient's medical history is the first stage in the diagnosis of pneumonia. Your doctor will inquire about your symptoms, their onset, and their development.

Be prepared to discuss any recent illnesses, travel, contact with sick people, or known pneumonia risk factors including smoking or chronic lung diseases.

  • Physical Examination: During a physical examination, your healthcare provider will check your vital signs, listen to your lungs, and look for any signs of pneumonia. They will pay attention to any abnormal sounds in your lungs, such as crackles or wheezing.
    Pneumonia can cause symptoms like fever, increased respiratory rate, and decreased oxygen saturation.
  • Chest X-ray: One of the first imaging tests needed to identify pneumonia is frequently a chest X-ray. It can assist distinguish between bacterial and viral pneumonia and show which parts of the lung are infected.
    X-rays can also identify the extent and location of the infection.
  • Blood Tests: To help confirm that there is an illness and identify its origin, blood tests including a complete blood count (CBC) and a blood culture may be performed.

Pneumonia may be indicated by an elevated white blood cell count and other infection-related indicators.

  • Sputum Culture and Analysis: A sample of your sputum (lung mucus) may be taken and submitted to a lab for testing if you are producing it. Especially in the case of bacterial pneumonia, this can assist in identifying the precise microorganism responsible for the infection, which is crucial for directing treatment.

Sputum cultures can also reveal whether the pneumonia-causing bacteria are antibiotic-resistant.

  • Pulse Oximetry: A non-invasive test called pulse oximetry can determine how much oxygen is saturating your blood. It aids in determining the extent of the pneumonia and whether additional oxygen is required.
  • Additional Tests: If the diagnosis is not apparent or if there are complications, more tests can be required, such as a chest CT scan or bronchoscopy (a technique to inspect the airways and collect samples).
  • Clinical Assessment: Your healthcare provider will decide the severity of pneumonia, its likely cause (bacterial, viral, or fungal), and the best course of therapy based on the findings of these tests and the clinical evaluation.



  • Diagnosis and Evaluation: Clinical assessment, medical history, physical examination, and diagnostic testing like chest X-rays, blood tests, and occasionally sputum cultures are used to diagnose pneumonia.

To choose the best course of action, it is essential to pinpoint the precise etiology of pneumonia.

  • Antibiotics or Antiviral Medications: Antibiotics are typically used to treat bacterial pneumonia. The bacteria that are thought to be present or have been detected depend on which antibiotics they are sensitive to.

Antiviral drugs can be used to treat viral pneumonia, which is brought on by viruses like influenza or the respiratory syncytial virus (RSV). These are less frequent, though, and for some viruses, vaccination is essential for protection.

Antifungal drugs are necessary for fungal pneumonia.

  • Supportive Care: For the body to fight the infection and preserve energy, proper rest is crucial.

Water intake is essential. Drinking plenty of liquids will help patients keep hydrated, which can thin mucus and improve the effectiveness of coughing.

Acetaminophen or ibuprofen, both available over-the-counter, can help lower temperature and ease discomfort.

Although expectorants and cough suppressants may be prescribed to treat cough symptoms, they should only be used sparingly because coughing helps clear the lungs.

  • Oxygen Therapy: Oxygen therapy might be required in severe cases if there is a considerable drop in blood oxygen levels. This can be given through a face mask, nasal prongs, or in more serious situations, a ventilator.
  • Hospitalization: Hospitalization may be necessary in some pneumonia cases, particularly in elderly, young, and immune-compromised patients.

Patients who have severe symptoms, a high fever, respiratory problems, or complications must also be hospitalized.

  • Prevention and Vaccination: There are vaccines for certain prevalent causes of pneumonia, including the pneumococcal and influenza vaccines.

The risk of pneumonia can be decreased by using proper hand hygiene, avoiding close contact with infected people, and leading a healthy lifestyle.

  • Follow-Up Care: Even if they begin to feel better, patients should still take the complete course of antibiotics or antiviral drugs as prescribed by their doctor.

To make sure the infection has vanished and to keep an eye out for any residual symptoms or problems, follow-up appointments are crucial.

If you suspect pneumonia, it's critical to speak with a healthcare provider for an accurate diagnosis and treatment strategy. Early and effective therapy can greatly enhance results and reduce problems.


Preventive Measures:

  • Vaccination: Encourage vaccination against pneumonia-causing agents that can be avoided, such as influenza and pneumococcal vaccines.
  • Hygiene: To stop the spread of infectious pathogens, encourage appropriate hand hygiene habits and cough control.
  • Smoking Cessation: It's important to motivate individuals who smoke to stop, as smoking harms the respiratory system and makes one more susceptible to respiratory infections.
  • Nutrition: Ensure patients receive adequate nutrition to support their immune system during recovery.



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