A 17y.o. with sudden onset of sore throat
What do you see on the CXR?
Hint: Dr. Grass will know
Our patient had a pneumomediastinum. He had been lifting weights as part of an army fitness evaluation and had a sudden onset of neck pain.
It was first described by Laenek in 1827. The physiology was first evaluated in cats where increased alveolar pressure caused a rupture of alveoli the air migrates through the peribronchial and perivascular sheaths to the mediastinum.
Air visible at the arrows
Pneumomediastinum occurs in 1/44,500 ED visits. It is more frequent in children than adults presumably because mediastinal tissues are loose where in the elderly planes are fiborosed. It is more common in patients with asthma and those with a tall, lean body habitus. Scuba divers and airplane passengers are at risk for pneumomediastinum. It has been reported in meth users presumably because of forced Valsalva . It can occur in esophageal rupture but in that case is often associated with a pleural effusion.
THE FINDINGS
The presentation is often chest pain or neck fullness. Rhinolalia (a nasal sounding voice) may also occur because of dissection of air into the soft palate. Hamman’s crunch, a mediastinal sound , may be heard over the lower sternum. Most cases of spontaneous pneumomediastinum resolve spontaneously but there have been reported cases of malignant pneumomediastinum where there is so much air in the mediastinum that venous return is compromised.
Air is much easier to see on the CT , especially in the neck
In 40% of cases where all types of pneumomediastinum are considered, there is a pneumothorax. Be on the look out for this in your trauma patients with pneumothorax.
THE DIAGNOSIS
A CT is useful in ruling out other causes of pneumomediastinum like pneumopericardium, ruptured airway or ruptured esophagus. The gold standard for esophageal perforation would be a swallow study. Our patient had a CT which is shown below. He was admitted to thoracic surgery and a repeat cxr was done in the AM. He was improved at that point and discharged.
Sahni S. Verma,a S. Grullon J. et al. Spontaneous pneumomediastinum: time for consensus. A Am J Med Sci 2013;5:460-4.
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Macklin M, Macklin C. Malignant interstitial emphysema of the lungs and mediastinum as an important occult complication in many respiratory disease and other conditions: an interpretation of the clinical literature in light of laboratory experiment. Medicine 1944;18:242-7.
Nicol E, Davies G, Jayakumar P, et al. Pneumopericardium and pneumomediastinum in a passenger on a commercial flight. 2007. Aviat Space Environ Med. 78(4):435-9.
Kouritas, Papagiannopoulos, Lazaridis, Baka, et al. Pneumomediastinum. 2015 J Thorac Dis Feb;7(Suppl 1) S44-49.