Pneumomediastinum is a rare condition. Epidemiology of pneumomediastinum reflects the epidemiology of diseases associated with the condition.

• The pneumomediastinum is a rare entity, diagnosed approximately 2.25 per 100,000 of accident and emergency admissions.^[1][2]
• Pneumomediastinum has an incidence of 1 per 100,000 natural births, being more frequent in children (6-125 per 100,000 individuals).

• Pneumomediastinum is a clinical condition with potential complications that can cause high morbidity and mortality rates.
• A retrospective review of medical records from January 1, 2002, to December 31, 2011, was conducted at a university-based urban trauma center.^[3]
  • According to the study, 72 patients out of 3327 (2.2%) patients with blunt trauma had pneumomediastinum.
  • Patients with pneumomediastinum had higher Injury Severity (ISS) Scores (P < 0.001) and chest Abbreviated Injury Scale (AIS) scores (P < 0.001) compared with those without pneumomediastinum.
  • Pneumomediastinum was associated with higher mortality (9 [12.5%] vs 118 [3.6%] patients; P < 0.001) and longer mean (SD) hospital stays (11.3 [14.6] vs 5.1 [8.8] days; P < 0.001), intensive care unit stays (5.4 [10.2] vs 1.8 [5.7] days; P < 0.001), and ventilator days (1.7 [4.2] vs 0.6 [4.0] days; P < 0.03).
  • According to the study pneumomediastinum size was not associated with in-hospital mortality (P = 0.22). However, the location of air in the posterior mediastinum was associated with increased mortality of 25% (7 of 28 patients; P = 0.007).
  • Air in all mediastinal compartments was also associated with increased mortality of 40.0% (4 of 10 patients; P = 0.01). Presence of hemothorax along with pneumomediastinum was associated with mortality of 22.2% (8 of 36 patients; P = 0.01).

• Patients of all age groups may develop pneumomediastinum.
• Infants have high incidence rates of pneumomediastinum.
• The incidence of pneumomediastinum is high in the general population between the ages of 5 and 34 years, with the predominance being young adult men and pregnant women.
• In a retrospective study, a prevalence of 30 per 100,000 children presenting in the emergency room with underlying asthma and acute exacerbation was reported. Mean age was 11.8 years with a male:female ratio of 1.15:1.^[4]
• 70% of cases of pneumomediastinum in children are due to exacerbation of asthma or respiratory tract infection.

• There is no racial predilection to pneumomediastinum.

• Adult males are more commonly affected by pneumomediastinum than females. The male to female ratio is approximately 8:1.^[5]
• In children male:female ratio is 1.15:1.

Geographical location has no effect on epidemiology of pneumomediastinum.