What Causes Lung Consolidation?

Medically reviewed by Susan Russell, MD

Long consolidation occurs when air in the lungs is replaced with pus, blood, or fluid. When lung tissue develops consolidation, it appears solid on imaging studies rather than filled with air, which is what a healthy lung would show.

Consolidation indicates a health issue. Causes of consolidation include pneumonia, aspiration, and lung cancer.

This article describes some of the conditions that may cause lung consolidation, how the condition is diagnosed, and how it's treated.

What Are the Symptoms of Lung Consolidation?

The symptoms of lung consolidation depend on what is causing it. Infection, pulmonary edema, lung cancer, aspiration, and pulmonary hemorrhage are some of the diseases that can cause consolidation. Symptoms that are common to all of these conditions include cough and shortness of breath.

People with pneumonia, lung cancer, or heart disease may experience chest pain or wheezing. Hemoptysis (coughing up blood) may be seen with pneumonia, lung cancer, or pulmonary hemorrhage. Pneumonia is often associated with fevers.

What Causes Lung Consolidation?

A variety of conditions can cause lung consolidation.

Pneumonia

Pneumonia refers to inflammation of the lung tissue. When most people use the term, they are referring to inflammation caused by bacterial or viral infection. This inflammation causes the air spaces of the lung to fill with fluid or pus.

Less commonly, pneumonia may be used to describe inflammation of the lungs due to something other than infection (for example, organizing pneumonia, a type of lung tissue repair after injury).

Pulmonary Edema

The term "edema" means swelling. Pulmonary edema, then, refers to swelling of the lung tissue. As pulmonary edema progresses, the air spaces can fill with fluid, causing consolidation. Pulmonary edema can be divided into two categories, cardiogenic and non-cardiogenic pulmonary edema:

• Cardiogenic pulmonary edema happens when the heart cannot effectively pump blood, leading fluid to back up into the lung tissue. Patients with myocardial infarction (heart attacks) or chronic heart failure can develop pulmonary edema, as can some patients with kidney failure or severe hypertension (high blood pressure). Heart valve problems or other chronic diseases may also lead to cardiogenic pulmonary edema.

• Non-cardiogenic pulmonary edema refers to pulmonary edema not caused by the heart. Examples of this include acute respiratory distress syndrome (ARDS), clots in your lungs (pulmonary embolism, or PE), altitude sickness, and exposures to certain drugs, smoke, or toxins.

Pulmonary Hemorrhage

A number of diseases can cause pulmonary hemorrhage, or bleeding into the lung tissue. This includes certain types of infection, pulmonary embolism, pulmonary vasculitis, lung cancer, or autoimmune diseases.

Regardless of the cause, pulmonary hemorrhage may cause consolidation on imaging that is difficult to distinguish from other causes of consolidation. The presence of lung consolidation in a patient with hemoptysis (coughing up blood) and anemia is highly suggestive of pulmonary hemorrhage.

Aspiration

In pulmonary aspiration, foreign substances are inhaled into the lungs. Food, water, blood, or gastric acid may be accidentally aspirated. Large amounts of aspirated material may cause irritation and inflammation of the lungs. This can show up on lung imaging scans as areas of consolidation, especially in the lung bases.

People who are hospitalized are at increased risk for aspiration because they spend most of their time lying on their backs and may have tubes placed in their stomach or airway. Anyone with a decreased level of consciousness is also at increased risk for aspiration, including those who are sick, intoxicated, or have recently had a seizure.

Atelectasis

Atelectasis refers to the collapse of lung tissue. Mild cases of atelectasis are often seen in people who just had surgery. It is thought to be due to blockage of the small lung airways by secretions. People in hospital intensive care units (ICUs), those in pain, and those who are somnolent (sleepy or drowsy) may not take deep breaths, limiting lung expansion and increasing their risk of atelectasis. Other causes of atelectasis include blockage of a large lung airway or compression of the lung by fluid collection.

On imaging, atelectasis appears as areas of consolidation and is often hard to distinguish from pneumonia or aspiration. Making the right diagnosis is complicated by the fact that these conditions may coexist and occur in patients with similar risk factors. Your history and physical exam findings may help your care provider distinguish between atelectasis and other conditions.

Related: When Is Coughing up Blood an Emergency?

Lung Cancer

Lung cancer is the overall leading cause of cancer death. It is often identified on routine chest X-rays or CT scans. It may appear as a rounded nodule or mass, which may be described as a "spot."

Sometimes, signs of lung cancer do not appear clearly on scans. It can cause consolidation that is difficult to distinguish from pneumonia, pulmonary hemorrhage, or other diseases. If lung cancer blocks a normal airway, it may cause pneumonia as a complication (post-obstructive pneumonia).

Because lung cancer can have a variety of appearances, patients with consolidation will often get follow-up imaging to make sure that the imaging abnormality has resolved. Lung consolidation that doesn't go away after treatment raises the suspicion of lung cancer.

Though your care provider may suspect lung cancer on the basis of an imaging study, the only way to confirm the diagnosis is through a biopsy, in which a small amount of tissue is removed for analysis in a lab.

What’s the Difference Between Lung Consolidation and Pleural Effusion?

Pleural effusion is the buildup of fluid between the chest cavity and the tissue lining the lungs. This is different than lung consolidation, which is fluid or other material that consolidates inside the lung.

Both conditions will show up on an X-ray as white against the air inside the lungs, which appears dark. However, the fluid in pleural effusion will move around when you change positions, while the material in a lung consolidation won't move because it's trapped inside the lung.

How Is Lung Consolidation Diagnosed?

Lung consolidation may be first identified during a physical examination by a healthcare provider. They may then order imaging of the chest—often a chest X-ray or CT scan—to confirm that consolidation is present.

The cause of consolidation on imaging may not be immediately obvious. Your healthcare provider will take a history and conduct a physical examination, looking for signs of infection or heart disease. They will look for conditions that place you at risk for aspiration or diseases that cause pulmonary hemorrhage.

Sometimes the appearance of lung consolidation on imaging can be helpful in determining the cause. Pulmonary edema, for example, tends to occur in the lower portions of the lungs (the lung bases). Consolidation related to tuberculosis (TB) infection is often located in the upper lungs.

If doctors suspect that the consolidation is due to lung cancer, they will need a sample of tissue to confirm the diagnosis. This can be obtained with a lung biopsy.

How Is Lung Consolidation Treated?

The treatment of consolidation depends on the cause.

Pneumonia

Treatment for pneumonia depends on the cause, but will typically be treated with antibiotics, antiviral therapy, or antifungals.

Pulmonary edema

Pulmonary edema can be addressed by treating the underlying heart condition or by removing excess fluid through diuretics.

Pulmonary hemorrhage

This can be treated with antibiotics if it is due to infection, blood thinners (anticoagulants) if it is due to blood clots, or immunosuppressants if it is due to autoimmune disease.

Aspiration

If aspiration causes pneumonia, it will likely be treated with antibiotics. If you have inflammation but no pneumonia, you may be given steroids.

Atelectasis

Atelectasis may be treated by suctioning out the obstructing mucus or using airway clearance therapy to loosen mucus so that patients can cough this out and clear blocked airways.

Lung Cancer

Depending on the type and stage of cancer, treatment may include surgery, chemotherapy, and/or radiation.

Summary

Consolidation occurs when the normal, air-filled spaces of the lung are filled with the products of disease. It may be caused by atelectasis, infection, pulmonary hemorrhage, aspiration, or lung cancer. Doctors often use the term when describing a finding on imaging of the chest, like an X-ray or CT scan. The treatment of consolidation depends on the cause, and the prognosis may vary depending on the severity of the disease and your other health conditions.

Read Next: What Does It Mean to Have a Shadow on the Lung?

Frequently Asked Questions

What does lung consolidation mean in terms of pneumonia?

The term "pneumonia" refers to inflammation of the lungs, and people usually use the term when describing lung inflammation due to viral or bacterial infection. "Consolidation" occurs when the air spaces of the lungs are filled with something other than air. In pneumonia, the pulmonary air spaces may fill with fluid, causing them to be "consolidated."

Is lung consolidation life-threatening?

Not necessarily. The causes of lung consolidation can range from fairly benign to truly life-threatening. Your prognosis depends on what is causing the consolidation and what other diseases you have (comorbidities). Your healthcare provider will take a history and perform a physical examination to determine the cause of consolidation and determine whether you are at risk for developing severe disease.