Stages of Lobar Pneumonia

Pneumonia is a lung infection that occurs due to bacterial, viral, and fungal infections. Sometimes it occurs due to complications of some other condition like influenza or Covid-19 infection.

The lungs have 3 lobes on the right and 2 lobes on the left. Pneumonia is divided into 2 groups depending on the areas of the respiratory system affected.

• Bronchopneumonia: It is a type of pneumonia affecting the bronchi and bronchioles, which are the system of tubes that bring air into and out of the lungs.
• Lobar Pneumonia: It refers to pneumonia that causes congestion and inflammation also known as consolidation affecting the entire lobe of the lung.

Bronchopneumonia from its initial stage progresses to lobar pneumonia. Lobar pneumonia has 4 stages or phases of infection.

Pneumonia is a leading cause of death worldwide and lobar pneumonia is a more fatal form of infection as it encompasses the whole lung.⁽¹⁾

Lobar pneumonia moves through phases but death can occur in any of these stages.

1. Congestion

   It is the first stage of infection when pneumonia has dominated one lobe of the lung. It lasts for around 24 hours and the lungs get inflamed, red, and weighed down by infection. On examination, the lungs would show engorged blood vessels and swelling in the tiny air sacs where oxygen and carbon-di-oxide are exchanged.

   The symptoms of this stage of pneumonia include:

   • Congestion
   • Fever
   • Chest pain
   • Wet cough with sputum

2. Red Hepatization

   This is the second stage of lobar pneumonia and lasts for a few days. The immune cells in this stage accumulate in large numbers in the spaces around the alveoli to fight the infection.

   The swelling in the alveoli is replaced with fibrous tissue and making the lung tissue dry and firm. This makes it difficult for the alveoli to move gases and oxygen into the bloodstream. The red blood cells carrying oxygen and other nutrients can burst and leak. This gives lung tissues a red appearance under the microscope.

   The symptoms of this stage of lobar pneumonia include:

   • Weakness and tiredness
   • Sputum production
   • Coughing
   • Increase in swelling in the alveoli
   • Shortness of breath
   • Difficulty breathing

3. Gray Hepatization

   This stage is known to occur 2-3 days after red hepatization and can last up to 8 days. As the red blood cells are destroyed the fibrous tissue and secretions increase. There is an accumulation of hemosiderin, a protein that stores iron in the tissue. This leads to staining and discoloration of lung tissue, giving a gray or darkened appearance under a microscope.

   The symptom of this stage include:

   • Increase in cough and sputum production
   • Shortness of breath
   • There may be a need for supplemental oxygen or even mechanical ventilation

4. Resolution

   It is a stage in which the enzymes and immune cells mount a defense against the infection and dissolves fibrous growth that restricts gas exchange. Macrophages clear dead tissue debris and restore the alveoli’s function.

   Symptoms of the resolution phase include improvement in shortness of breath. There may be an increase in cough and sputum as the body works to clear the lungs.

Most respiratory infections clear in 2-3 weeks. If the cough lasts more than 2-3 weeks even with the medication, a doctor should be consulted.

Pneumonia is mostly treated with antibiotics that target the cause of pneumonia. A person may also find relief with treatments like:

• Rest
• Fever medication
• Humidifier
• Fluids to thin the secretions and mucus

In the red and gray hepatization phase, intravenous antibiotics and fluids may be needed. A person may also need supplemental oxygenation.

Viral pneumonia may require anti-viral medications that shorten the course of the disease. In severe cases, drainage of fluid from the lungs may be needed.

Pneumonia can be fatal and lobar pneumonia is its serious type. It occurs when one or all the five lobes of the lung get infected. This makes the movement of oxygen and other gases difficult. If you think, you have developed shortness of breath after a period of illness, see a doctor.