Abstract
BACKGROUND: Hamman's sign is a rare phenomenon. Louis Hamman described this pathognomonic clicking chest noise in association with pneumomediastinum in 1937. This typical noise can also be present in left-sided pneumothorax. Clinical cases already mention this pericardial knock in 1918 in gunshot wounds of the left chest and in 1928 in cases of spontaneous left-sided pneumothorax. However, the sound itself has only rarely been recorded. CASE SUMMARY: We describe a case of a young man with no significant medical history who was referred to the hospital with chest pain and audible clicks, documented with his smartphone. Imaging studies including chest radiograph and computed tomography scan revealed a left-sided pneumothorax. The patient underwent semi-urgent insertion of a thorax drain. His clinical outcome was excellent. DISCUSSION: In recent years only a few case reports describe Hamman's sign, as it is rare and happens only transiently. This case report includes the audible clicks recorded by the patient with his smartphone. We stress the importance of thoracic clicking sounds as key symptom in the differential diagnosis of left-sided pneumothorax, pneumomediastinum, and valvular pathology such as mitral valve prolapse.