Lung cysts are a manifestation of BHD syndrome. They are also called pulmonary cysts, lung blebs and bullae. The cysts are sacs in the lung tissue that are filled with air and so can be detected by radiological tests, such as an X-ray or a CT scan, which make the air visible.
The cysts are prone to rupture at any time. However, changes in external air pressure can cause the bleb to break open, such as when scuba diving or flying in an aeroplane, or even when listening to loud music or taking a very deep breath. The air from the ruptured bleb then enters the space in between the lung and the chest wall (called the pleural space) and creates pressure on the lungs. Consequently, part of the lung or the whole lung may collapse.
Please see Spontaneous pneumothorax for more information regarding how to detect and deal with a suspected pneumothorax. If you have lung cysts, it is advisable to avoid high altitudes, scuba diving, and flying in unpressurised aeroplanes. You may want to discuss air travel and other activities with your doctor.
As with other manifestations of BHD syndrome, the presence, onset and quantity of lung cysts vary from family to family, and individual to individual. Lung cysts are one of the most common symptoms of BHD syndrome in some families, while others are hardly aware of their existence. Currently, researchers are examining situations which increase the risk of spontaneous pneumothorax, such as the number and location of lung cysts, as well as investigating the symptoms produced by different BHD mutations.
