What is Pneumomediastinum?
Pneumomediastinum is a term used to refer to the abnormal presence of air in the center of the chest. The center of the chest is known as the mediastinum, and it sits between your lungs. The mediastinum contains your heart, the thymus gland, and part of the trachea and esophagus.
It is possible for air to get trapped in the mediastinum due to various causes such as an injury, or due to leakage from the trachea, esophagus, or the lungs. It is not a condition that you hear about often. Read on to learn more about what is Pneumomediastinum and whether it is a serious condition.
What Causes Pneumomediastinum?
There can be many causes of pneumomediastinum.(1) This condition typically happens when the pressure increases in the lungs, causing the air sacs or alveoli to rupture. Damage to the lungs or other nearby organs, which allows air to begin leaking into the center cavity of the chest.
Some of the other causes of pneumomediastinum include:
- Injury to the chest area
- A tear in the lungs or esophagus due to a surgical procedure or an injury
- Surgical procedure of the chest, neck, or even the upper belly
- Any activities that put a lot of pressure on your lungs, such as childbirth or strenuous exercise
- Use of a breathing machine
- A rapid change in air pressure such as from going up very quickly while scuba diving
- Condition that leads to intense bouts of coughing, such as lung infections or asthma
- Chest infections such as tuberculosis
- Diseases or infections that lead to lung scarring
- Abuse of inhaled drugs such as marijuana or cocaine
Practicing the Valsalva maneuver, which is a technique that involves blowing hard while bearing down to pop your ears(2)
Spontaneous pneumomediastinum (SPM) is another form of this condition that does not have an identifiable cause. Pneumomediastinum is a very rare condition, and it only affects one person in 7,000 and 1 in 45,000 people who are admitted to the hospital. One baby in every 10,000 is born with this condition.(3)
Children and newborn babies have a higher risk of getting pneumomediastinum than adults because the tissues in their chest are not as tight and can allow the air to leak.
Other risk factors of pneumomediastinum include:
Lung disease: Pneumomediastinum is more likely to affect people with lung diseases such as pneumonia and asthma.
Gender: Men are more likely to get pneumomediastinum than women, especially men who are in their 20s to 40s.(1)
What are the Symptoms of Pneumomediastinum?
The primary symptom of pneumomediastinum is chest pain that can come on all of a sudden and can be severe. Other symptoms of pneumomediastinum include:
- Neck pain
- Shortness of breath
- Difficult or shallow breathing
- Trouble swallowing
- Hoarse or nasal voice
Air present under the skin of the chest, a condition known as subcutaneous emphysema
Your doctor might also be able to hear a crunching sound that is in tune with your heartbeat while listening to your chest through a stethoscope. This symptom is known as Hamman’s sign.(4)
There are two imaging tests that are used to diagnose pneumomediastinum:
CT Scan: Computed tomography (CT) scan makes use of X-rays to create a detailed picture of the lungs. A CT scan can show whether there is air trapped in the mediastinum.
X-Ray: X-ray use small doses of radiation to get pictures of the lungs. X-rays are used to find the cause of the air leak.
There are other tests also that are used to check for a tear in the lungs or esophagus. These include:
- Esophagoscopy in which a tube is passed down the nose or mouth to get a clear view of the esophagus.(5)
- Esophagogram in which an X-ray of the esophagus is taken after you swallow barium.(6)
- Bronchoscopy, in which a thin, illuminated tube known as a bronchoscope is inserted into the mouth or nose to check the airways.(7)
Treatment of Pneumomediastinum
Pneumomediastinum is not a serious condition as the leaked abnormal air that is present will eventually get reabsorbed into the body. The primary goal of the treatment of pneumomediastinum is to manage the symptoms in the meantime.(1)
Most people are kept overnight in the hospital for monitoring, and after that, the treatment consists of:
- Pain relievers
- Bed rest
- Cough medication
- Anti-anxiety drugs
- Antibiotics, especially if there is an infection involved
Some people may need to be given oxygen to help them breathe. Oxygen is also used to help speed up the reabsorption of air in the chest cavity.
Pneumomediastinum can sometimes happen with pneumothorax, which is a collapsed lung that is caused by the accumulation of air between the chest wall and the lungs. People who have a collapsed lung may need to have a chest tube to help in draining out the air.
Newborns and Pneumomediastinum
Pneumomediastinum is a very rare condition, not just in adults, but even more so in babies. It affects only 0.1 percent of all newborns.(8)
Doctors believe that pneumomediastinum in newborns is caused due to the difference in pressure between the air sacs and the tissues surrounding the air sacs. The air starts leaking from the air sacs and enters the mediastinum.
Pneumomediastinum is commonly observed in babies who:
- Have pneumonia or other lung infections
- Are on a mechanical ventilator to help them breathe
- Who breathe in the meconium, or their first bowel movement
Some babies may have pneumomediastinum, but not have any symptoms. Others may experience symptoms of breathing distress, such as:
- Flaring of the nostrils
- Abnormally fast breathing
Babies who are experiencing these symptoms are given oxygen to help them breathe. If pneumomediastinum is being caused by an underlying condition, then that is treated with antibiotics. The babies are then carefully monitored to make sure that the air gets reabsorbed.
Pneumomediastinum is not a serious condition, though the symptoms of the condition such as shortness of breath and chest pain can definitely be frightening. Spontaneous pneumomediastinum usually tends to improve on its own, and once the condition goes away, it generally does not come back. Pneumomediastinum can last longer or even return if it was initially caused by drug abuse or an illness such as asthma. If you are experiencing any symptoms of pneumomediastinum, it is best to talk to the doctor to avoid any complications.
- Kouritas, V.K., Papagiannopoulos, K., Lazaridis, G., Baka, S., Mpoukovinas, I., Karavasilis, V., Lampaki, S., Kioumis, I., Pitsiou, G.,
- Papaiwannou, A. and Karavergou, A., 2015. Pneumomediastinum. Journal of thoracic disease, 7(Suppl 1), p.S44.
- Porth, C.J., Bamrah, V.S., Tristani, F.E. and Smith, J.J., 1984. The Valsalva maneuver: mechanisms and clinical implications. Heart & lung: the journal of critical care, 13(5), pp.507-518.
- Meireles, J., Neves, S., Castro, A. and França, M., 2011. Spontaneous pneumomediastinum revisited. Respiratory Medicine CME, 4(4), pp.181-183.
- Baumann, M.H. and Sahn, S.A., 1992. Hamman’s sign revisited: pneumothorax or pneumomediastinum?. Chest, 102(4), pp.1281-1282.
- Gualtieri, M., 2001. Esophagoscopy. The Veterinary clinics of North America. Small Animal Practice, 31(4), pp.605-30.
- Kostic, S.V., Rice, T.W., Baker, M.E., DeCamp, M.M., Murthy, S.C., Rybicki, L.A., Blackstone, E.H. and Richter, J.E., 2000. Timed barium esophagogram: a simple physiologic assessment for achalasia. The Journal of thoracic and cardiovascular surgery, 120(5), pp.935-946.
- Fulkerson, W.J., 1984. Fiberoptic bronchoscopy. New England Journal of Medicine, 311(8), pp.511-515.
- Corsini, I. and Dani, C., 2014. Clinical management of the neonatal pneumomediastinum. Acta Biomed, 85(1), pp.39-41.