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Pneumonia: Causes, Symptoms, Risk Factors, Diagnosis, Treatment And Prevention

Pneumonia is the infection of the lungs in which the air sacs (known as alveoli) get filled with pus or fluid causing inflammation and difficulties while breathing. The infection is caused mainly by bacteria. However, it can be caused by other microorganisms like virus and fungi. [1]

Streptococcus pneumoniae, a Gram-positive bacterium, is the most common cause of pneumonia. A yeast-like fungus named Pneumocystis jiroveci is another germ responsible for this lung condition while among viruses, the flu virus is considered to cause pneumonia.

Pneumonia is life-threatening when it affects older people, infants, chronic disease patients or people with a weakened immune system. According to a study, there were around 0.56 million severe episodes of pneumococcal pneumonia (due to Streptococcus bacteria) in India in 2010. Also, 0.35 million children under the age of 5 years died due to the disease. The highest number of cases of pneumonia are reported in the states of Bihar, Uttar Pradesh and Madhya Pradesh. Simultaneously, the top 5 countries affected by this lung infection are India, China, Bangladesh, Pakistan and Indonesia. [2]

Causes Of Pneumonia

Multiple numbers of bacteria, fungi and virus are responsible for causing pneumonia. They are of 4 types:

  • Bacterial pneumonia: Mainly caused by bacteria named Streptococcus pneumoniae [3]
  • Atypical pneumonia: Caused due to atypical or unique-featured bacteria such as Mycoplasma pneumoniae (Walking pneumonia), Legionella pneumophila (Legionnaires' disease) and Chlamydia pneumoniae (Chlamydia pneumonia) [4]
  • Fungal pneumonia: It mainly affects people with a weakened immune system or some chronic health condition. They are usually found in the soil and also varies according to the location. [5]
  • Viral pneumonia: Cold and flu viruses are responsible for causing pneumonia. [6]

Types Of Pneumonia

1. Hospital-acquired pneumonia (HAP): It is also known as nosocomial pneumonia and develops in an individual within 48-72 hours when he/she is hospitalised for another illness. It can be serious as the individual is sick and the bacteria that have affected, have already adapted themselves to the antibiotics. People on breathing ventilators are at high risk of HAP. [7]

2. Community-acquired pneumonia (CAP): It is a common type of pneumonia acquired outside the healthcare facilities. CAP is the leading cause of mortality and morbidity among other infectious disorders. [8]

3. Healthcare-acquired pneumonia (HCAP): It occurs in non-hospitalized patients who live in a long-term care facility, comes in contact during intravenous therapy or one who receive outpatient treatment in hemodialysis clinic or hospital. They are mainly at risk of multidrug-resistant organisms. [9]

4. Aspiration pneumonia: It occurs when a person aspirates saliva, solid foods, or vomit into the lungs instead of the stomach. Such particles cause infection in the lungs. [10]

Symptoms Of Pneumonia

Symptoms of pneumonia can range from mild to severe. Its occurrence depends on the type of microorganism, age, health and other medical conditions of the patient. However, common symptoms include the following:

  • Cough with phlegm [11]
  • Fever or chills
  • Shortness of breath
  • Fatigue
  • Fast heartbeat [12]
  • Sweating
  • Diarrhoea [13]
  • Headache
  • Cyanosis, bluish or greyish discolouration of the skin [14]
  • Chest pain

Risk Factors Of Pneumonia

The risk of pneumonia is high in people who fall under the following categories:

  • Above age 65 [15]
  • Below age 2 [16]
  • With a weak immune system like HIV patients, chemotherapy patients and organ transplant patients [1]
  • With autoimmune disorders like rheumatoid arthritis and multiple sclerosis [17]
  • With lung conditions like asthma, pulmonary fibrosis and bronchiectasis
  • Hospitalized or under breathing ventilators
  • Smoke or drink [18]
  • With neurological conditions like Parkinson's disease
  • Exposed to industrial toxic smoke for a long time
  • Pregnant [19]

Complications Of Pneumonia

Complications of pneumonia include the following:

  • Spread of bacteria in the blood (Bacteremia)
  • Fluid build-up in the area between pleura and chest wall (pleural effusion) [20]
  • Lung abscess
  • Empyema (a collection of pus develops in the cavity) [21]
  • Meningitis (the infection spread to the meninges of the brain)
  • Septic arthritis (when the bacteria transfer to the joints)

Diagnosis Of Pneumonia

Diagnosis of pneumonia includes the following processes:

  • Medical history: To determine a patient's age, any medical condition, occupation, recent illness, recent travel and other details
  • Physical exam: Determined by placing a stethoscope on the chest of the patient to hear bronchial breath sounds
  • X-ray: To find out the location and extent of lung inflammation
  • Blood test: To identify the type of microorganism causing pneumonia [22]
  • Pulse oximetry: To monitor the saturation of oxygen in the patient's blood
  • Sputum test: To find out whether it is a bacterial or fungal infection
  • Bronchoscopy: Here, a thin lighted tube is inserted into the airways to visualize its internal portion. [23]

Treatment Of Pneumonia

Treatment of pneumonia depends on its types and severity. Common treatment methods include the following:

  • Medications: Antibiotic medicines are used to treat bacterial pneumonia, antifungal medication for pneumonia caused due to fungus and antiviral drugs for viral pneumonia. These medications are taken for weeks to clear the infection of the lungs. [24]
  • Over-the-counter medications: To manage the symptoms of pneumonia such as fever, cough and muscle pain
  • Oxygen therapy: Given when the oxygen level in the blood is low [25]
  • Respiratory therapy: Here, specific medicines are delivered directly into the lungs.

Tips To Deal With Pneumonia

  • Quit smoking [18]
  • Cover while coughing or sneezing
  • Wash hands with disinfectant at regular intervals
  • Strengthen the immune system by a healthy diet plan and exercise
  • Stay hydrated throughout the day [26]
  • Managing ongoing medical conditions by timely medications
  • Take a lot of rest
  • Drink warm beverages or take steamy baths to ease your breathing
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