A lung bleb is a small, air-filled sac that forms on the surface of the lung, just beneath the visceral pleura, the membrane covering the lung. These formations are often discovered incidentally and cause no immediate symptoms, but they represent a structural weakness in the lung tissue. The potential for a bleb to rupture is a serious medical concern, as it can lead to a collapsed lung. Understanding the nature and management of these air pockets is important.
What Exactly Are Lung Blebs
Lung blebs are small, air-filled cysts or blisters on the lung surface, typically measuring less than one centimeter in diameter. They are distinct from pulmonary bullae, which are larger air-filled cavities, usually exceeding one centimeter, and are often located deeper within the lung tissue. Blebs form when the tiny air sacs, or alveoli, just below the lung surface weaken and rupture, allowing air to collect in the subpleural space.
These structural changes are most frequently found in the apex, or very top, of the lungs. They are commonly associated with primary spontaneous pneumothorax, which most often affects tall, thin young men between the ages of 18 and 40. Smoking is a significant contributing factor, as it can damage lung tissue and lead to the development of these fragile air pockets. The presence of blebs indicates a localized area of structural vulnerability in the lung’s outer layer.
Do Lung Blebs Resolve Spontaneously
The vast majority of lung blebs, once they have formed, are permanent structural alterations and do not resolve or disappear on their own. They represent a type of permanent air pocket that persists over time. Because they are rarely symptomatic unless they rupture, the standard medical approach for unruptured blebs is conservative management, also known as “watchful waiting.”
This approach involves monitoring the blebs through imaging to check for any changes rather than expecting them to shrink or vanish. The reason for their persistence is that the underlying structural damage to the lung tissue does not heal in a way that allows the air pocket to be fully reabsorbed. Extremely rare instances of spontaneous resolution have been documented, but these typically involve very large bullae, which is an unusual course for the smaller, common bleb. For most patients, the bleb is a fixed feature of the lung anatomy.
Recognizing the Risk of Collapsed Lung
The primary health concern related to a lung bleb is the risk of it rupturing, which causes a spontaneous pneumothorax, or collapsed lung. Rupture allows air to leak from the lung surface into the pleural space, the area between the lung and the chest wall. This accumulation of air builds pressure, preventing the lung from fully expanding.
The symptoms of a collapsed lung appear suddenly and require immediate medical attention. Patients often experience a sharp, stabbing chest pain on one side, typically made worse by taking a deep breath or coughing. This is usually accompanied by sudden shortness of breath and rapid, shallow breathing. A rapid heart rate and a bluish tint to the skin, lips, or nails (cyanosis) can signal a larger or more severe collapse that demands emergency intervention.
Treatment Strategies for Persistent Blebs
Treatment for lung blebs is generally reserved for individuals who have already experienced a pneumothorax or are considered to be at a high risk for recurrence. When a bleb ruptures and causes a minor lung collapse, the initial treatment may involve simply observing the patient or using a needle to aspirate the free air from the chest cavity. Larger collapses often require the insertion of a chest tube to actively drain the air and allow the lung to re-expand.
If a patient experiences a recurrent collapsed lung, or if the blebs are particularly large or numerous, a surgical procedure is usually recommended to prevent future episodes. The preferred method is Video-Assisted Thoracoscopic Surgery (VATS), a minimally invasive procedure that uses a small camera and instruments inserted through tiny incisions.
During VATS, the surgeon removes the bleb-containing section of the lung, a procedure known as a blebectomy. To further reduce the risk of recurrence, a procedure called pleurodesis is often performed. Pleurodesis involves creating a controlled irritation or abrasion of the outer lung and inner chest wall lining to cause them to adhere together.