Tracheobronchial diverticulum, a potential risk for diving?

Abstract Background: Tracheobronchial diverticulum(TBD) is a cystic lesion outside the lumen of the trachea and bronchus. This is the first report case of a SCUBA(Self Contained Underwater Breathing Apparatus) diver diagnosed with tracheo diverticulum(TD), which is a potential risk to diving. So far no literature or guideline is available on the diving fitness for patients with such a condition. Case presentation: An asymptomatic 26-year-old male professional diver has a history of SCUBA diving up to depth of 40 m. He did not have any diving-related injuries or symptoms and had no history of smoking, drinking, or other special illnesses except for a COVID-19 infection. A tracheal diverticulum was found by computed tomography(CT), but its communication with the trachea was not clear. Therefore, high-resolution CT and electronic bronchoscopy were used to clarify the situation of diverticulum and identify the diving risk. High-resolution CT showed a possible opening of diverticulum, but this was not seen under electronic bronchoscopy. Conclusion: Although a potential opening was showed in high-resolution CT, the lack of visual bronchoscopic evidence made it likely to be a dead cavity. As such, there is a higher theoretical risk of barotrauma during decompression, leading to pneumomediastinum, hemorrhage or arterial gas embolism. Take it into consideration, the current clinical consensus is that air-containing tissue should be regarded as relative contraindications to diving. Overall speaking, it is recommended that the diver need to dive carefully and avoid rapid decompression.