The lungs consist of tiny air sacs called alveoli. Emphysema damages the alveoli and destroys lung tissue. Bullous emphysema (BE) refers to damaged alveoli that distend to form large air spaces, especially in the top of the lung.

BE is a radiographic diagnosis according to chest X-rays or, more commonly, a CT scan of the chest showing the presence of bullae. Bullae typically measure 1 centimeter (cm) or more in size, and imaging shows that pockets of air give the appearance that the lung is disappearing. As such, radiographers use the term “vanishing lung syndrome,” although clinicians do not typically use this terminology.

This article describes what BE is, including its symptoms, treatment, and diagnosis. It also lists some other types of emphysema.

A scan showing bullous emphysema.Share on Pinterest
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The lungs contain multiple tiny air sacs called alveoli, which help exchange oxygen and carbon dioxide when a person breathes in and out.

Emphysema is a type of chronic obstructive pulmonary disease (COPD) that causes damage to the walls of the alveoli.

BE occurs when the alveoli walls break down, resulting in large air pockets called bullae. These pockets measure 1 cm or more and are less effective at moving oxygen and carbon dioxide.

The condition can occur in one lung or both. Bullae within one lung can restrict the expansion of the opposite lung, resulting in breathing difficulties in both organs.

The two most common causes of BE are tobacco smoking and alpha-1 antitrypsin deficiency. Other conditions that correlate with the development of bullae in the lung can include:

BE is a serious condition that may cause permanent changes in the lung.

In BE, the enlarged air spaces are less efficient at exchanging oxygen and carbon dioxide. This inhibited airflow reduces the amount of oxygen available to the rest of the body.

BE affects 12% of adults over the age of 30 years worldwide. In the United States, the condition ranks third in causes of death.

People living with emphysema are also more likely to develop a collapsed lung, called a pneumothorax. A collapsed lung can be life threatening in people with severe emphysema because their lung function is already compromised.

A person with BE may have one or more small bullae or a giant bulla measuring up to 20 cm. A giant bulla can cause several symptoms, including:

There is currently no cure for COPD, and the outlook for BE depends on the management of the underlying disease and possible interventions for bulla in the lung.

If a person smokes, stopping smoking will help slow the progression of the disease.

And if an individual has a giant bulla that causes symptoms, their doctor may recommend surgery to remove it.

When treating BE, a doctor will typically prescribe inhaled medications to help with symptoms of COPD. They work by:

  • dilating the airways to aid with airflow in and out of the lungs
  • addressing inflammation in the airways
  • easing shortness of breath

A person may also receive oxygen if their oxygen saturation is low.

Surgery is sometimes an option if bullae are large or there are complications, such as:

  • pneumothorax, a collapsed lung
  • hemoptysis, the medical term for coughing up blood from the lungs or airways
  • an infection

Surgery may involve removing the entire bullae, which doctors call a bullectomy. They could also remove a portion of the tissue that the emphysema affects most. Doctors refer to the latter as lung volume reduction surgery. This is a procedure to help individuals breathe easier when they have lung damage from severe COPD. Alternatively, healthcare professionals may recommend a bronchoscopic lung volume reduction, a minimally-invasive procedure for people with severe emphysema.

To diagnose BE, a doctor will use imaging, such as chest X-rays and CT scans.


A chest X-ray is a simple, nondetailed image of the lungs and is usually the first imaging test for evaluating most lung diseases. A chest X-ray can determine general bullae features, including identifying larger bullae and establishing bullae location, such as in the upper or lower lung.

CT scan

CT scans of the chest have greater sensitivity and are more specific than X-rays when detecting emphysema. However, a person does not normally require a CT scan for diagnosing COPD.

Usually, a doctor will order a CT scan if:

  • an individual has a change in symptoms that suggests COPD complications, such as pneumonia
  • a person receives an alternate diagnosis, such as a pulmonary embolism
  • a person receives a lung cancer indication from a screening

Certain CT scan features can determine whether the emphysema is:

Chest CT imaging allows for a more detailed view compared with chest X-rays, so a clinician can better categorize and measure the number and size of bullae. They can also obtain more detailed information about where they are.

A doctor will seek to determine a person’s lung function by ordering a pulmonary function test (PFT). PFTs are noninvasive tests that show how well the lungs work. They measure:

  • lung volume
  • lung capacity
  • rates of flow
  • gas exchange

This information can help a doctor or healthcare professional diagnose and treat specific lung disorders.

Emphysema is a serious, lifelong lung disease that may eventually leave a person short of breath. It has various types, identifiable by radiographic imaging of the chest.


Paraseptal emphysema or “distal acinar emphysema” is emphysema that primarily affects the upper portion of the lungs. The condition can develop into BE.

Paraseptal emphysema can cause damage that leads to empty spaces in a person’s lung tissue over time. If they get too big, individuals may be at risk of a collapsed lung.


Panlobular emphysema affects the entire lung or its lower lobes. The condition can occur due to the following:

  • Aging: The disease can occur due to typical, age-related lung changes.
  • Tobacco smoking: Smoking is a common cause of emphysema.
  • Alpha-1 antitrypsin deficiency: A rare inherited disorder that may cause lung disease.
  • Ritalin lung: Lung changes related to injecting talc-containing methylphenidate, such as Ritalin.
  • Obliterative bronchiolitis: A disease in which the smallest airways of the lungs become obstructed due to inflammation.
  • Swyer-James syndrome: A lung condition where a lung or part of a lung does not grow properly following obliterative bronchiolitis.


Subcutaneous emphysema occurs when air gets underneath the skin. It most often affects the skin on the chest or neck, but it can also affect other parts of the body.

Subcutaneous emphysema is a condition where air becomes trapped under the skin. Emphysema simply means “air,” while “subcutaneous,” or under the skin, refers to the location of the air. This type of emphysema is different from other types in this article — they are diseases of the lungs. Additionally, the condition is not a result of smoking.

Subcutaneous emphysema is generally a side effect of another trauma event, such as:

  • a collapsed lung
  • a facial bone fracture
  • a tear in the airway
  • a rupture in the esophagus or gastrointestinal tract

Subcutaneous emphysema sometimes develops after specific infections or after scuba diving.

BE is a type of emphysema that doctors usually diagnose with chest imaging techniques such as X-rays or CT scans. These tests can reveal large pockets of air or bullae within one or both lungs.

Bullae can range in size from 1 to 20 cm. Doctors refer to large bullae as giant bullae, which may take up a third or more of the space in and around the affected lung. Large bullae are more likely to cause symptoms.

BE treatments typically involve addressing and managing COPD to help with breathing difficulties. Doctors may also recommend surgery to remove giant bullae that are causing symptoms.

Doctors closely associate emphysema, a type of COPD, with smoking. Quitting smoking is one of the most important steps to slow the progression of the disease. Individuals can speak with a healthcare professional for further advice on quitting smoking.