The 4 stages of pneumonia

Pneumonia: Simple Breakdown Of Its 4 Stages!

Pneumonia: Lung Infection

Pneumonia Is actually an infection in the lungs (It is an illness that infects both of the lungs or just one). The infection caused by either Bacteria, Viruses, or Fungi, causes inflammation in the air sacs in the lungs which are called Alveoli. The alveoli make it difficult to breathe because they are filled with fluid or pus.

Pneumonia is classification is based on the part of the lungs it’s infecting: There is Bronchopneumonia which can affect parts within both of the lungs. It is usually located near or around the bronchi ( the bronchi are the tubes that lead from the windpipe to the lungs).

And there is also Lobar Pneumonia, this type affects single or multiple lobes which are defined sections of the lung. There are indeed four stages of lobar pneumonia classified based on its progression:

1- Congestion.

2- Red Hepatization.

3- Grey Hepatization.

4- Resolution.

This table below demonstrates and breaks down the 4 stages stated above:

Congestion is the first stage of pneumonia which occurs within the first 24 hours of getting infected. Throughout this phase:

– The body will suffer from vascular engorgement, intra-alveolar fluid, and multiple bacteria.
– The lungs will become quite heavy and red.
– The infection will spread to the hilum and pleura as the Capillaries in the alveolar walls become congested.
– Deep breathing and coughing.
Red Hepatization
  Red Hepatization is the phase that occurs after two to three days from congestion. Throughout this phase:

– The lungs will become red, firm, and airless similar to the liver.
– Vascular Congestion will persist as the alveolar capillaries will be engorged with blood.
– The alveoli will contain multiple erythrocytes, neutrophils, desquamated epithelial cells, and fibrin.  
Grey Hepatization
Grey Hepatization is the phase the occurs two to three days after red hepatization and is an avascular stage. Throughout this stage:

– The disintegration of red cells will cause the lungs to appear to be a grayish brown or yellow color, and also they will become paler and drier than usual.
– Persistence of fibrin exudate.
Resolution is the complete recovery and it occurs when the exudate experiences progressive enzymatic digestion. Which will produce debris that is eventually reabsorbed, ingested by macrophages, coughed up, or reorganized by fibroblasts.  

Is Pneumonia Contagious?

Actually, some forms of pneumonia can be contagious while some other forms are non-contagious.

The two types of pneumonia that are contagious are Bacterial pneumonia which includes: Chlamydial pneumonia, streptococcal pneumonia, Methicillin-resistant Staphylococcus aureus pneumonia, and walking pneumonia. And also Viral pneumonia which can be caused by viruses that infect the respiratory system, or the same viruses responsible for flu and colds.

While the noncontagious types of pneumonia are fungal pneumonia which normally infects individuals who suffer from severe health issues or a weak immune system. The reason is that this type is caused by inhaling fungi that are normally found in soil and not spread from a person to another. And aspiration Pneumonia occurs by inhaling liquid or food directly to the lungs.

How To Prevent The Spread Of Pneumonia.

There are several ways for an individual to get infected with viruses that might cause pneumonia. Here some tips to utilize in order to prevent the spread of pneumonia.

The obvious is to take a vaccine and you should consider consulting with a doctor to determine the type of vaccine suitable for you and your family. Not that vaccines are the most important and efficient way to fight off bacterial as well as viral infections in both adults and children.

When you are caring for someone who suffers from pneumonia, always wash your hands in a regular way. And if you are smoking, STOP.

Keep a healthy diet and exercise regularly to keep your body in a good condition. Also, keep your distance from sick people as much as you can.


We are passionate about making people's lives easier by providing valuable health information as we spend countless hours of research on health issues and problems. As a disclaimer, we are an informational website and NOT doctors, You need to consult with professional doctors for any health problems.

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