Pneumomediastinum

Upper Respiratory Tract

Head and neck infection (odontogenic, salivary glands, cervical adenitis, tonsillitis, peritonsillar abscess, osteomyelitis of facial bones)

Fractures (involving paranasal sinuses, orbit, mandibles, other facial bones)

Other mucosal disruption (trauma, surgery, attempted endotracheal intubation)

Dental procedures (extractions, air-turbine drilling)

Intrathoracic Airways

Blunt or penetrating chest trauma

Foreign body

Iatrogenic (bronchoscopy, bronchial brushing, transbronchial biopsy, needle aspiration)

Neoplasm

Lung Parenchyma

Direct disruption of alveoli (penetrating trauma, surgery, transbronchial biopsy, needle aspiration)

"Spontaneous" alveolar rupture (between alveolus and adjacent bronchovascular sheath) *

Gastrointestinal Tract

Esophageal perforation

Via pneumoperitoneum or pneumoretroperitoneum (gastric or intestinal perforation, diverticulitis, pneumatosis cystoides intestinalis, endoscopy, biopsy, infection)

Infection with gas-producing organisms

Acute bacterial mediastinitis

Head and neck infections

Air from Outside the Body

Penetrating trauma to neck or chest

Surgical procedures (tracheotomy, mediastinoscopy, sternotomy)

Via subcutaneous emphysema in association with chest tube insertion

Artificial pneumothorax

Artificial pneumoperitoneum

Alveolar Rupture: Reported Clinical Settings