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What Are the 4 Stages of Pneumonia?

Nov 30, 2021


Pneumonia is a serious infection that affects the lungs, particularly in children, older adults, and those with weakened immune systems. The lungs are made up of air sacs that expand and contract with the air you breathe in and out. If fluid or pus gets into those air sacs, it can lead to symptoms of pneumonia. In order to diagnose pneumonia, your doctor will likely want to run a series of tests, including blood tests to confirm if an infection is present, pulse oximetry to measure the level of oxygen in your blood, and a chest X-ray. An X-ray of your chest can help your doctor get a better look at your lungs and better assess what stages of pneumonia you are experiencing. A CT scan can also provide more detailed images of your lungs and chest. Visit an Atlanta Imaging Center near you to get a chest X-ray and CT scan. Your doctor can also talk to you about the four stages of pneumonia and your treatment options.

What Is Pneumonia?

Pneumonia is a lung infection that can be caused by many different kinds of germs. Both bacteria and viruses can infect the lungs and cause serious complications, including pneumonia symptoms. The body’s immune system is designed to fight these germs, but sometimes they can take root and cause you to get sick. There are different types of pneumonia based on what causes pneumonia and how you acquired the infection. The most common type of pneumonia is community-acquired pneumonia, which means you picked up the infection while going about your daily life. You may get a cold or the flu that turns into pneumonia. The COVID-19 virus can also end up causing pneumonia because it weakens the lungs. Another type of pneumonia occurs when you acquire it in a health care or hospital setting. Hospital-acquired pneumonia may occur while you are in the hospital due to picking up bacteria. People in the intensive care unit are at greater risk of developing pneumonia. People who visit outpatient clinics or live in long-term care facilities can also develop a bacterial infection that can cause pneumonia.

Symptoms of Pneumonia

Pneumonia can range from mild to severe, and the symptoms you experience can also range in severity. A case of mild pneumonia may have similar symptoms of a cold or flu, though the pneumonia symptoms typically last longer. Common signs and symptoms of pneumonia include coughing, chest pain while breathing or coughing, fatigue, fever, sweating, chills, and shortness of breath. Some people with pneumonia also experience symptoms such as nausea, diarrhea or vomiting. Adults over age 65 also tend to experience pneumonia symptoms like a lower than normal body temperature and confusion or challenges with mental awareness. If you develop a fever, experience chest pain, have difficulty breathing, and are in a high-risk category, visit your doctor to determine whether or not you have pneumonia.

Stages of Pneumonia


The first stage of pneumonia is the congestion phase. The symptoms of pneumonia you are likely to experience include coughing, fatigue, loss of appetite, rapid breathing, and a sense of pressure and heaviness in the chest. This is caused by the fluid building up in the air sacs of the lungs.

Red Hepatization

The second stage of pneumonia is red hepatization, which refers to the body’s initial immune response to the fluid in the lungs. The body sends red blood cells and immune cells to the area to help combat the pneumonia infection. During this stage, you may experience continued coughing, shortness of breath, extreme fatigue, fever, and chills.

Gray Hepatization

The third stage of pneumonia is gray hepatization, which is when the red blood cells that moved to the lungs to help fight the infection begin to disintegrate. When the red blood cells are active in stage two, the lungs have a reddish appearance, but once they disintegrate, the lungs take on a gray color.


The final stage of pneumonia involves the resolution of many symptoms of pneumonia. As the immune cells are able to properly rid the body of infection, you will start to feel better and experience relief from pneumonia symptoms.Visit your Atlanta Imaging Center at AICA Orthopedics for a wide range of diagnostic imaging services, including chest X-rays and CT scans.


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