Discussion

Pneumomediastinum is the presence of free air within the mediastinal cavity. It may occur spontaneously or secondary to trauma, airway injury, or underlying lung pathology. Spontaneous pneumomediastinum (Hamman’s syndrome) is a rare, usually self-limiting condition seen predominantly in young males, commonly presenting with chest pain, dyspnea, and subcutaneous emphysema. The suspected pathophysiology in pneumomediastinum is commonly explained by the Macklin effect, in which increased intra-alveolar pressure leads to alveolar rupture and air leakage into the mediastinum.

Susai et al. highlighted the importance of computed tomography, especially when chest radiography is inconclusive or when complications are suspected [2]. In our patient, the chest radiograph demonstrated pneumomediastinum with subcutaneous emphysema, while CT confirmed the diagnosis and more precisely defined the extent of mediastinal and subcutaneous air, facilitating appropriate clinical management.

The patient presented with chest pain, chest tightness, and shortness of breath, and was found to have subcutaneous emphysema around the neck and chest progressing to the face and upper limbs. Crepitus was present from the face to the abdomen. Morgan et al. reported that most patients with primary spontaneous pneumomediastinum have identifiable precipitating factors, such as smoking, cough, asthma, physical exertion, and retching, none of which were present in our patient [11].

A systematic review of 339 cases of spontaneous pneumomediastinum conducted by Alemu et al. noted that the mean age of patients affected with spontaneous pneumomediastinum was 22.4 ± 11.3 years, highlighting the unusual presentation in our elderly patient, who was 63 years old. Chest pain was found to be the most common presenting symptom, seen in 57.8% of cases, along with dyspnea (46%), cough (28%), and neck swelling (27.13%). Similar to the findings in the review, our patient presented with acute chest pain, dyspnea, and extensive subcutaneous emphysema. The mean duration for clinical resolution of spontaneous pneumomediastinum was reported to be 6.65 ± 11.8 days, comparable to our case, which was resolved within a week. Hamman's sign is regarded as a classic but relatively uncommon physical finding in spontaneous pneumomediastinum, reported in only 11.2% of the total cases; however, it was clearly seen in our patient, illustrating the continued clinical value of careful physical examination despite widespread availability of advanced imaging [12].

Generally, spontaneous pneumomediastinum with subcutaneous emphysema follows a self-limiting course, and no specific therapy is needed [13]. Consistent with the recommendations of Takada et al., our patient was managed conservatively with oxygen therapy and close observation [14]. However, the extensive progression of subcutaneous emphysema necessitated intercostal drainage, illustrating that individualized management may occasionally be required.

The patient was treated with high-flow oxygen through an NRBM and was kept under close observation for signs of respiratory distress. Following treatment, the patient showed gradual clinical improvement and was discharged in stable condition.