An Overview of Pneumomediastinum

Pneumomediastinum is a rare condition where air or gas becomes trapped in the chest. The mediastinum is the portion of your chest between the lungs that contains the heart, esophagus, trachea and large blood vessels. This conditions is also sometimes called pneumomediastinum emphysema.

Air can escape from the lungs or trachea or even bowel to become trapped in this area of the body. This is usually the result of trauma but occasionally the cause cannot be identified (spontaneous pneumomediastinum).

Pneumomediastinum is more common in boys than girls and while it can occur at all ages it is more likely to occur in children because or babies because their chest consists of more cartilage and softer tissue than the chests of adults.

Symptoms

Symptoms will vary depending on your individual situation, the severity of the pneumomediastinum and the underlying cause. In general symptoms of pneumomediastinum may include:

• Severe pain in the center of the chest which may radiate to the neck or back (most common)
• Subcutaneous emphysema (also common, may cause a crackling sound called crepitus when the skin above the area is palpated)
• Difficulty breathing
• Coughing spells
• Neck pain
• Vomiting
• Difficulty swallowing
• Peumothorax (rare)
• Anxiety

Causes

A wide variety of factors may lead to pneumomediastinum including but not limited to:

• Injury (especially to the chest)
• Surgical complications
• Respiratory diseases including asthma, COPD, bronchiectasis, or cancer of the lungs
• Excessive coughing, vomiting, or even the Valsalva maneuver
• Difficult childbirth
• The use of recreational drugs
• Barotrauma caused by scuba diving or rapid altitude changes
• A complication of mechanical respiratory ventilation
• Choking
• Inhalation of toxic fumes

Diagnosis

Pneumomediastinum is a rare condition, however, mild cases of it are thought to be underdiagnosed. If pneumomediastinum is suspected the test most often used to confirm diagnosis is a simple chest X-ray which will show air bubbles or streaks in the mediastinum. Other tests are rarely needed but if they are they may include:

• Ultrasound
• Bronchoscopy
• Esophagoscopy or esophagography 

Hamman’s sign is sometimes present and this is defined as a distinct crunching sound or click when a certain area of the chest is listened to with a stethoscope.

If a cause of pneumomediastinum is not immediately identified additional tests may be used to rule out an underlying illness (for example pulmonary function tests to look for asthma or other lung conditions).

Treatment

Identifying the underlying cause of pneumomediastinum and addressing it is an important factor in treatment. For example, if the pneumomediastinum is caused by an asthma attack the first phase in treatment focuses on stopping the attack and restoring adequate respiration.

After underlying causes that need to be immediately addressed have been taken care of treatment focuses on managing symptoms until the condition resolves. The body will gradually reabsorb the air in the mediastinum.

The following treatments may be used to control symptoms and speed up the reabsorption of air:

• Pain medications or anti-anxiety medications to increase comfort
• Cough suppressants
• Bedrest
• Oxygen
• Hospital observation

Prognosis

The prognosis of pneumomediastinum is actually very good and complications are extremely rare.

Malignant pneumomediastinum is an unlikely but serious complication where enough air becomes trapped in the mediastinum to cause obstruction of the trachea (windpipe) or the large blood vessels in the area. This may also lead to a condition called tamponade where the heart becomes surrounded by fluid and compressed. Few cases of malignant pneumomediastinum have been reported.

Coping

While the prognosis of pneumomediastinum is good and complications of the condition are a rarity the experience can be quite scary. Significant pain accompanied by anxiety are often present. Medications can be used to control these symptoms but talking about your experience with a loved one or friend can also be very valuable.

If your pneumomediastinum is accompanied by the diagnosis of a new illness such as asthma or another lung disease this may lead to other coping challenges. It is highly recommended that you reach out to family, friends, and your medical team for help. Having a strong support system will be crucial and your medical team may be able to connect you with support groups, financial help, or medical specialists that can help you to adjust to and manage a new diagnosis.