Spontaneous pneumomediastinum is a rare medical condition characterized by the presence of air within the mediastinum, the central compartment of the chest. This phenomenon occurs without any identifiable external injury or medical procedure. It is generally considered a benign condition, often resolving on its own.
What is Spontaneous Pneumomediastinum?
The mediastinum is the space in the middle of your chest, between the lungs. It contains vital organs like the heart, major blood vessels, the trachea, and the esophagus. In spontaneous pneumomediastinum, air leaks from the airways or lungs and collects in this central cavity.
The “spontaneous” nature means the air leak happens without obvious trauma or medical procedures. Instead, air typically originates from ruptured alveoli, small air sacs in the lungs. The air then travels along blood vessels and airways, accumulating in the mediastinum.
Common Causes and Risk Factors
Spontaneous pneumomediastinum often results from activities that significantly increase chest pressure. Forceful actions like intense coughing, repeated vomiting, or strenuous physical exertion can cause a sudden rise in intrathoracic pressure, leading to the rupture of delicate lung air sacs and air escape.
Other contributing factors include asthma attacks, severe sneezing, and pushing during childbirth. Inhaled recreational drugs, such as marijuana or crack cocaine, have also been associated with this condition due to forceful inhalation. While many cases have an identifiable trigger, sometimes no clear cause is found, especially in younger, healthy individuals.
Recognizing the Symptoms
Individuals experiencing spontaneous pneumomediastinum commonly report sudden, sharp chest pain behind the breastbone. This pain may spread to the neck or arms and can worsen with breathing or swallowing. Shortness of breath is another frequently reported symptom, affecting approximately 31% to 75% of patients.
A distinctive but less common symptom is Hamman’s sign, a crunching or clicking sound heard with each heartbeat when a medical professional listens to the chest. Other signs can include a change in voice, such as hoarseness or a high-pitched tone, and sometimes difficulty swallowing. Swelling in the face or neck due to air pockets under the skin, known as subcutaneous emphysema, is also a possible finding, observed in about 35% to 70% of cases.
Diagnosis and Treatment Approaches
Diagnosing spontaneous pneumomediastinum typically involves a physical examination and imaging studies. During the examination, a healthcare provider might detect subcutaneous emphysema or Hamman’s sign. To confirm the diagnosis, a chest X-ray is often the initial imaging test, revealing air outlining mediastinal structures in about 90% of cases. A computed tomography (CT) scan of the chest provides a more detailed view and effectively confirms air in the mediastinum.
Treatment for spontaneous pneumomediastinum is primarily supportive, as the condition is self-limiting and the body gradually reabsorbs the escaped air. Patients are typically advised to rest, and pain management is provided as needed. Oxygen therapy can be administered to help speed up air reabsorption. While surgery is rarely necessary, doctors will rule out more serious underlying conditions that might present with similar symptoms, such as an injury to the esophagus or trachea.