From the Guidelines
Pneumomediastinum is primarily caused by the dissection of air from the lungs or airways into the mediastinum, which can occur due to traumatic injuries or non-traumatic causes.
Common Causes
- Traumatic injuries, such as blunt trauma to the chest or penetrating injuries
- Non-traumatic causes, including asthma exacerbations, inhalation of illicit substances, and certain medical procedures, such as bronchoscopy or mechanical ventilation with high positive end-expiratory pressure (PEEP) settings
Less Common Causes
- Certain medications, including inhaled corticosteroids and bronchodilators, may also contribute to the development of pneumomediastinum in susceptible individuals
- Extra-peritoneal perforations, such as perforations of the descending colon and rectum, can cause air to track along the mesenteric and fascial planes, even into the mediastinum 1
- Colonoscopy may also dissect within the wall of the colon with pneumatosis, leading to air dissection into the mediastinum 1 Key factors that contribute to the development of pneumomediastinum include the presence of air leaks from the lungs or airways, increased pressure within the thoracic cavity, and the presence of fascial planes or other pathways for air to dissect into the mediastinum.
Diagnostic Considerations
- Computed tomography (CT) scans with contrast enhancement can easily detect small amounts of free intra-peritoneal air and fluids, and can show air tracking along the mesenteric and fascial planes, even into the mediastinum 1
- Double contrast CT (intravenous and rectal) may be useful for detecting concealed or sealed perforations that are eligible for non-operative management 1
- Multi-detector CT (MDCT) is superior to single helical or conventional CT because it can provide rapid, high-volume coverage, and diagnostic images, even in patients who are unable to perform prolonged breath holds 1
From the Research
Causes of Pneumomediastinum
Pneumomediastinum, also known as mediastinal emphysema, can be caused by various factors. The condition is divided into two subgroups: Spontaneous Pneumomediastinum (SPM) and Secondary Pneumomediastinum (ScPM) 2.
- Spontaneous Pneumomediastinum (SPM) can occur without any identifiable cause, but certain conditions that increase intrapleural pressure, such as coughing, vomiting, or vigorous exercise, may predispose to its occurrence 3.
- Secondary Pneumomediastinum (ScPM) can be further divided into Traumatic Pneumomediastinum (TPM) and Iatrogenic Pneumomediastinum (IPM) 2.
- Traumatic Pneumomediastinum (TPM) is caused by trauma to the thorax, while Iatrogenic Pneumomediastinum (IPM) is caused by medical procedures 2.
- Other causes of pneumomediastinum include performing the Valsalva maneuver during labor, which may play a role in the development of SPM in pregnant women 4.
- Additionally, pneumomediastinum can be caused by factors such as strenuous sports or cocaine inhalation, although in some cases, the cause may be idiopathic 5.
Clinical Presentation
The clinical presentation of pneumomediastinum can vary, but common symptoms include chest pain, dyspnea, subcutaneous emphysema, and cough 2, 3, 4, 5.
- In some cases, pneumomediastinum can lead to more serious complications, such as pneumothorax, pneumopericardium, pneumoperitoneum, or pneumoretroperitoneum 6.
- The diagnosis of pneumomediastinum can be made using imaging studies, such as chest X-ray or computed tomography (CT) scan 2, 5.
Types of Pneumomediastinum
There are different types of pneumomediastinum, including:
- Spontaneous Pneumomediastinum (SPM): occurs without any identifiable cause 2, 3, 4, 5.
- Traumatic Pneumomediastinum (TPM): caused by trauma to the thorax 2.
- Iatrogenic Pneumomediastinum (IPM): caused by medical procedures 2.
- Pregnancy-associated Spontaneous Pneumomediastinum: occurs in pregnant women, often during labor 4.