Pneumomediastinum pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Trusha Tank, M.D.[2]

Overview

• Pneumomediastinum can happen when pressure rises in the lungs and causes the air sacs (alveoli) to rupture. Another possible cause is damage to the lungs or other nearby structures that allow air to leak into the center of the chest.

Pathophysiology

Physiology

The normal physiology of [name of process] can be understood as follows:

Pathogenesis

Spontaneous pneumomediastinum

• The pathophysiology of spontaneous pneumomediastinum is based on the existence of a pressure gradient between the alveoli and the lung interstitium.
• Sudden increase in intrathoracic pressure due to a specific triggering event such as Valsalva maneuver, vomiting, asthma exacerbation, physical activity may lead to alveolar rupture and the consequent escape of air into the interstitium.
• Once the air is in the lung interstitium it flows towards the hilum and the mediastinum along a pressure gradient between the lung periphery and the mediastinum.
• Predisposing factors of spontaneous pneumomediastinum are tobacco smoking, use of recreational drugs, past medical history of asthma, bronchial hyperreactivity and interstitial lung disease.
• One of the most important precipitating factors of spontaneous pneumomediastinum is the absence of any specific trigger.
• The other precipitating factors are physical exercise, vomiting, cough infection of the upper airways or inhalation of varnish fumes.

Secondary pneumomediastinum

• Secondary pneumomediastinum is resulted by blunt or penetrating trauma.
• Recent interventions in the esophageal or tracheobronchial tree, rupture of a hollow viscus, tissue dissection originating from spontaneous pneumothorax, pulmonary or mediastinal infection by gas-forming organisms.

• Secondary PM: Disruption of aerodigestive tract (trauma, foreign body, Boerhaave syndrome), surgery, mediastinitis

Genetics

[Disease name] is transmitted in [mode of genetic transmission] pattern.

OR

Genes involved in the pathogenesis of [disease name] include:

• [Gene1]
• [Gene2]
• [Gene3]

OR

The development of [disease name] is the result of multiple genetic mutations such as:

• [Mutation 1]
• [Mutation 2]
• [Mutation 3]

Associated Conditions

Conditions associated with [disease name] include:

• [Condition 1]
• [Condition 2]
• [Condition 3]

Gross Pathology

On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

Microscopic Pathology

On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].