Pneumonia (Lung Infection)

What is pneumonia?

Pneumonia is a condition where there are inflammatory changes in the lungs due to infection most commonly by bacteria. However viruses, fungi and even parasites are also capable of causing pneumonia. Certain other factors like intake of some drugs or autoimmune diseases may also lead to pneumonia.

Common symptoms of pneumonia include difficulty breathing along with fever and cough. Although anyone can suffer from pneumonia, it requires special attention in both young children and the elderly people as well as in people with weak immunity like cancer or HIV patients. Untreated pneumonia can be fatal.

These days with the advent of antibiotics, pneumonia can be successfully managed in most of the patients. Hospitalization is required only in the elderly or young children suffering from moderate to severe degrees of pneumonia.

Pneumonitis and Pneumoconiosis

Pneumonia is a term reserved for lung inflammation as a result of infection. However, there are various other non-infectious lung diseases that may have similar terms. Pneumonitis is another term for inflammation of the lungs but refers to inflammatory changes associated with chemical injury or even severe allergic reactions. Pneumoconiosis is a type of occupational lung disease associated with the inhalation of coal, asbestos and silica particles that compromises lung function over time.

Pneumonia Symptoms

Often mild degree of pneumonia mimics the symptoms of flu and presents with fever, body ache, tiredness and cough. With progression of disease, the more characteristic symptoms of pneumonia become evident. This includes :

  • High degree of fever with chill. Body temperature may fall below normal temperature in elderly patients.
  • Cough with sputum may be tinged with blood.
  • Shortness of breath with stabbing or sharp pain in the chest.

Complications of Pneumonia

The complications of pneumonia are more likely to be seen in babies, the elderly, frail patients of any age and immunocompromised patients. Pneumonia can sometimes become very aggressive even in healthy young adults. Untreated and severe pneumonia may lead to a number of complications like :

  • In pneumonia infection initially remains confined in the air sac (alveoli) but with progression of the disease infective organisms may spread via the blood stream to other organs.
  • Spread of infection in the blood may lead to leakage of plasma into the adjacent tissue resulting in organ failure and even death.
  • Fluid may accumulate in the pleura, the sac-like structure surrounding the lungs and the inner wall of the chest. In advanced cases pus can accumulate thereby causing empyema.
  • Acute respiratory distress syndrome (ARDS) may occur leading to severe shortness of breath and reduced oxygen supply to different organs.

Causes of Pneumonia

Pneumonia can occur due to number of causes but an infection is the most common one. Usually the natural body defense mechanisms prevent the entry of infective organisms into the lungs. Pneumonia can be of various types like :

  • Community acquired pneumonia where the person contracts infection from other people in their community. The most common organism is Streptococcus pneumoniae. Other common infecting organisms are Staphylococcus aureus, Haemophilus influenzae, Klebsiella species and other bacteria that commonly infect the respiratory system. Mycoplasma, Legionella and Chlamydia are the non-bacterial microorganisms which may lead to pneumonia. Some viruses like the influenza virus and fungi or parasites may also be responsible for pneumonia.
  • Hospital acquired pneumonia is a severe form of pneumonia that can affect patients admitted in nursing homes, hospitals, kidney dialysis centers and other health care institutions. Although Staphylococcus aureus is one of the most commonly infecting organisms, often drug resistant strains makes treatment difficult.
  • Aspiration pneumonia occurs when the acidic stomach contents enter the airways and reaches the lungs. Certain diseases like stroke and Parkinson’s disease may increase the risk of aspiration pneumonia.
  • Poor immunity as in patients suffering from HIV infection, with organ transplant and long term steroid intake increases the risk of suffering from viral, fungal or bacterial infections.

Risk factors

  • Age – infants or the elderly.
  • Pre-existing lung diseases like asthma, COPD and inhalation of chemicals (pneumonitis) or particles (pneumoconiosis).
  • Smoking.
  • Weak immune system.

Pneumonia Treatment

If pneumonia is diagnosed early and the patient is healthy, treatment can be very effective. However, some patients are less responsive to treatment and some strain of infective organisms are resistant to drugs. Treatment options include :

  • Antibiotic, antivirals and antifungals.
  • Antipyretics to reduce fever.
  • Cough suppressants.
  • Breathing support in severe distress, fluid replacement in case of fall in blood pressure.
  • Hospitalization is required in advanced cases.

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