Pneumonia is a contagious disease that spreads through droplets released to the air by coughing and sneezing. The human respiratory system is made up of an airway and a gas exchanging organ. Gas exchanging organ is the lung. Each lung contains millions of alveoli which are tiny membranous sacs connected to the airway by their proximal ends. The function of the alveoli is to exchange gas with the blood. An infection at the level of the alveoli is called as Pneumonia.


The infection may involve one or both the lungs. In each lung, a part (lobar or bronchopneumonia) or the lung may be diffusely involved.  It can range from a mild illness to a severe life-threatening condition, especially if left untreated.

Causes of pneumonia

Pneumonia is caused by microorganisms including bacteria, fungi, and viruses.  Out of them, bacteria are the commonest. Causative bacteria are again classified as typical and atypical according to the frequency of infection. The severity of the infection varies depending on the causative organism.

The commonest type is Community-acquired Pneumonia (CAP). The infective organism can be bacterial, viral or fungal. CAP infects the people while they are in the community, away from the healthcare sector. It’s usually mild and easily curable in immune-competent patients.

  1. Streptococcus penumoniae
  2. Haemophilus influenzae
  3. Mycoplasma pneumoniae are well-known bacteria to cause CAP

Hospital-acquired pneumonia (HAP) or nosocomial pneumonia is a severe form of Pneumonia that infects the hospitalized people. In HAP, the patient admits to the hospital due to another reason and during the time in the hospital he acquires Pneumonia due to pathogens inside the hospital. These pathogens tend to be more virulent and antibiotic-resistant; thus aggressive treatment is needed. HAP is particularly common among immune-deficient people and people who are being artificially ventilated.

  1. Pseudomonas aeruginosa
  2. Klebsiella pneumonia
  3. Acinetobacter species are notorious to cause HAP

Symptoms of Pneumonia

Symptoms of Pneumonia
  • Cough with phlegm (sputum) production.
  • Chest pain (lateralized to the site of infection)
  • Fever with chills and sweats
  • Difficulty in breathing
  • Low body temperature in elderly people
  • Nausea and vomiting

The color of the sputum is a good indicator of the causative organism; rusty color sputum in Streptococcus pneumoniae, green sputum in Pseudomonas infections.

The following symptoms indicate severe disease.

  • Bluish discoloration of the nailbeds and tongue (cyanosis)
  • Confusion or behavioral changes
  • Extreme fatigue

Pneumonia can affect any age group, but particularly common among infants, children and the elderly. Infants may not express any symptoms other than fever and vomiting. Elderly people (over 65 years of age) may not show symptoms until the infection has progressed to an advanced stage. Therefore, keen observation and consulting a doctor in suspicion is essential.

Risk factors

  1. Age below 2 years
  2. Age over 65 years
  3. Immune deficient people (People with diabetes or HIV)
  4. People who are receiving artificial ventilation
  5. People who are having treatments in ICU
  6. Debilitated, bedridden people

Complications of Pneumonia

  • Lung abscesses
  • Pleural effusions – Fluid collection in-between the chest wall and the lung; in the pleural cavity
  • Septic shock with multi-organ failure
  • Acute respiratory distress syndrome – A form of respiratory failure with severe damage to the alveoli
  • Death


Treatment varies depending on the causative organism. Viral pneumonia is managed symptomatically until the patient recovers himself. Sometimes antiviral drugs may be given. Bacterial Pneumonia is treated with Antibiotics depending on the antibiotic sensitivity patterns. If the infection is mild and the patient is less than 65 years of age, he can be managed as an outpatient with common antibiotics like Co-amoxiclav or erythromycin.

Treatment of Pneumonia

If the patient is over 65 years of age or has features of severe disease, immediate admission to the hospital and inpatient care should be considered. Inpatient management include,

  • Chest physiotherapy to clear the lung secretions
  • Intravenous antibiotics
  • Corticosteroids
  • Antipyretics to reduce the fever
  • Fluid resuscitation
  • Respiratory support with Broncho-dilating drugs and artificial ventilation
  • ICU admission

Prevention of Pneumonia

Vaccinations are available for Streptococcus pneumoniae and Haemophilus influenzae.

Wear a mask if you are seeing a patient with Pneumonia.

Always remember to cover your mouth, not by your hand, but by the sleeve of your shirt when you cough or sneeze.

See a doctor if you are having an infection of the respiratory tract with or without phlegm production

Smokers are vulnerable to acquire Pneumonia. Therefore, quit smoking.

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Author: Ahaana Sahay