A Case of the Crackly Chest – Pneumomediastinum

From the case files of Dr. Wendy Lau, Emergency Physician:

An 11 year old male with no significant past medical history presents with chest pain x 5 hours.  Patient states the pain started suddenly while running in school.  The pain is sharp, mid-sternal, and worse on inspiration.  The patient denies any sob, dizziness, or syncope.

On physical exam:

Vital signs are normal

General: Well appearing

Chest: lungs clear to auscultation bilaterally

You listen to the heart and hear the following:

What other parts of the physical exam might be significant? What tests would you order to confirm the diagnosis?

Chest x-ray demonstrated radiolucent streaks tracking along
the margins of the heart, within the retrosternal space, and surrounding the
trachea.

When you re-examine the patient, crepitus is noted in right neck soft tissue

So, what is your diagnosis?

Pneumomediastinum (PM): Free air contained within mediastinum – almost always originates from alveolar space or conducting airway.

Non-spontaneous PM – blunt/penetrating chest trauma, endobronchial or esophageal procedures, neonatal lung dz, mechanical vent, chest sx

Spontaneous PM

• Increased alveolar pressures
• Free air  tracks from ruptured alveoli along peribronchial vascular sheaths toward hilum of lung, then extends proximally within mediastinum; mediastium communicates with submandibular space, retropharyngeal space and vascular sheath within neck -> subq air in neck
• Triggering factor identified in 70-90%
• Vigorous cough – asthma cough being most common in children
• Valsalva
• Illicit drug ingestion
• Inhalation of illicit drugs, chemical compounds, commercial aerosol i.e. huffing
• Barotraumas – scuba diving/flying
• Vigorous vomiting – Boerhaave syndrome (esophageal rupture)
• Strenuous athletic activity, playing woodwind instruments

*Rarely leads to clinically significant complications
*Rarely tension pneumomediastinum -> decreased cardiac output – surgical emergency

Mortality variable based on underlying condition:

• Boerhaave – 50-70% due to mediastinitis
• Other high mortality etiologies  = Trauma – blunt or penetrating, trancheobronchial perforation
• But spontaneous pm is usually self-limited and rarely produce significant symptoms

Presentation:

• Chest pain
• Dyspnea – may reflect asthma, tension pm
• Dysphonia
• Throat pain
• Jaw pain

Workup:

• ABG depending on clinical status
• Cardiac enzymes
• Toxicology
• Chest x-ray
• Chest CT if suspecting perforated esophagus or trauma

Procedures:

• No chest tubes unless pneumothorax present
• Bronchoscopy if suspecting tracheobroncial perforation
• Esophagoscopy if suspecting Boerhaaves

Treatment:

• Nitrogen washout with 100% O2 suggested
• Analgesia

DC:

• Observation?
• No strenuous activity or forced expiration maneuvers until resolution

So, that’s the case. We’d like to hear your thoughts so post any comments below.

Thanks,

JK

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Jay Khadpe MD

• Editor in Chief of "The Original Kings of County"
• Assistant Professor of Emergency Medicine
• Assistant Residency Director
• SUNY Downstate / Kings County Hospital

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