Pneumomediastinum From Sports-Related Trauma
Key Findings and Recommendations
Kevin J. Curley, MD; Gary W. Dorshimer, MD;
THE PHYSICIAN AND SPORTSMEDICINE - VOL 31 - NO. # - MONTH 2021
In Brief: Pneumomediastinum can result from blunt chest trauma in sports. Diagnosis is made using chest radiography. The natural history of isolated pneumomediastinum is benign; however, it can be associated with more serious injuries, such as disruption of the tracheobronchial tree or a perforated digestive viscus. Patients with isolated pneumomediastinum should be monitored with serial chest radiographs. Patients may return to full activity once their chest radiographs have returned to normal, they exhibit no symptoms, and they have regained their stamina.
Pneumomediastinum is an unusual complication of athletic activity. Spontaneous pneumomediastinum has been reported as a consequence of activity in several sports such as scuba diving, rugby training, weight lifting, surf-lifesaving (an Australian form of competitive lifesaving), and mountain climbing.1-3 Pneumomediastinum arising from blunt trauma sustained during athletic activity, however, is exceedingly rare. A MEDLINE search of the literature from 1960 to the present revealed only five other cases of pneumomediastinum arising from trauma during athletic activity. Two cases occurred in soccer, one in football, one in the Japanese fencing sport of kendo, and one following trauma to the flank while playing ice hockey.3-5
Subcutaneous emphysema and pneumomediastinum can be associated with blunt or penetrating trauma.6 Pneumomediastinum may also occur following soft-tissue infections, or in conditions that produce a gradient between intra-alveolar and perivascular interstitial pressures.6-8 Common presenting symptoms of pneumomediastinum are acute pleuritic chest pain, dyspnea, and neck pain. Less common symptoms may include dysphagia, dysphonia, or abdominal pain.1,8,9
Air in subcutaneous tissue or the mediastinum is abnormal and should prompt an investigation into its source as well as a search for associated injuries.7,10,11 While mediastinal air per se is not dangerous, it can be associated with more serious conditions (table 1).6,7,10,11 Thus, when pneumomediastinum is recognized, it is vital to rule out other potentially significant conditions. In cases of uncomplicated pneumomediastinum, athletes may return to play once both symptoms and radiographic findings resolve.
A 27-year-old ice hockey player collided with an opposing player at center ice. His opponent's shoulder hit him in the chest. He then fell onto his back on the ice, and his opponent fell directly onto his chest. The patient was taken to the training room, where he described both anterior and posterior chest pain as well as dyspnea. Movements of the chest and deeper breaths increased his pain. Sitting seemed to be more comfortable than lying back on the examination table. He had parasternal and paraspinal tenderness to palpation. Vital signs were normal, and breath sounds were equal bilaterally. He had ice packs applied to his chest and back, was given analgesics, and was able to go home after the game.
When the patient was seen by his physician the next day, his pain was less severe. However, he still had right parasternal chest pain and tenderness, especially in the area of the right second costosternal junction. His back was nontender, and the lungs were clear to auscultation, with full and equal breath sounds bilaterally. Heart sounds were unremarkable. Subcutaneous air was palpable and crepitation evident at the right axilla.
Anteroposterior (AP) and lateral chest x-rays showed no evidence of pneumothorax or rib fracture but revealed subcutaneous emphysema and pneumomediastinum (figure 1). A subsequent computed tomography (CT) scan of the thorax confirmed these findings but showed no significant pathology, such as tears in the trachea or esophagus, pneumothorax, or rib fracture. The patient was managed conservatively: Treatment was with rest and analgesics, and he was monitored with serial chest x-rays. After chest x-rays showed that he had complete resolution of all subcutaneous and mediastinal air and after examination showed total improvement of his symptoms, he was able to return to play 1 week postinjury without further sequelae.
Addressing the Cause
Spontaneous pneumomediastinum has been recognized since the 17th century when Louise Bourgeois, midwife to the queen of France, observed that stabbing pains in the chest and subcutaneous crepitations were sometimes associated with extreme efforts during childbirth.7 Laennec first accurately described the condition in the setting of traumatic injury in his textbook on chest diseases, published in 1819.7 Knott was the first to report the association of subcutaneous emphysema and mediastinal emphysema in 1850 in a patient who had had a violent coughing episode.6 Hamman provided the first formal description of primary or spontaneous pneumomediastinum in 1939. He also described the physical examination finding of a crunching or crepitation sound, loudest at the apex and synchronous with systole, now known as Hamman's crunch.12 In 1944, Macklin reported the results of studies in cats that were fundamental in elucidating the probable mechanisms of pneumomediastinum.6-8,11
Causes. There are several ways in which air can be introduced into the chest and mediastinum. Gas-forming infections can produce air in the soft tissues, as occurs in mediastinitis. The mechanism responsible in cases of "spontaneous pneumomediastinum" is rupture of the alveoli. This is the most frequent cause of pneumomediastinum.7 Because of an increased pressure gradient between the intra-alveolar and perivascular interstitial spaces, alveolar wall rupture occurs with subsequent passage of air into the bronchovascular sheath. This increased pressure gradient can occur when either alveolar pressure rises or interstitial pressure decreases. Possible situations in which these conditions may take place include mechanical ventilation, scuba diving, mountain climbing, severe asthmatic attacks, violent coughing episodes, childbirth, Valsalva's maneuver, or inhalation of illicit drugs such as marijuana or crack cocaine.7-11 Finally, air may be introduced into the mediastinum following a traumatic event.
Trauma that causes disruption of any air-containing structure such as the paranasal sinuses, proximal airways, oropharynx, or hollow viscera of the digestive system can lead to pneumomediastinum and subcutaneous emphysema via direct transthoracic entrance.7,10 Cases have been reported following dental extractions or air-turbine drilling of lower molars.13 Chest-wall trauma may also lead to pneumomediastinum arising from alveolar rupture secondary to increased intra-alveolar pressure following compression of the chest. Microtears in the alveoli lead to air dissecting into the bronchovascular sheath, with air moving from the perivascular interstitium to the mediastinum. Because of fascial connections of the mediastinum to the soft tissues of the neck, air can travel in tissue planes to the neck and to other subcutaneous areas.7 In our case, the mechanism of injury was likely alveolar rupture due to either blunt trauma to the patient's chest or a Valsalva-type maneuver in anticipation of the impending blow.
Symptoms and diagnosis. The chest pain associated with pneumomediastinum is decreased when patients sit upright and lean forward, similar to the pains from pericarditis. Pain is worsened by lying supine. On physical examination, one may be able to palpate subcutaneous emphysema and auscultate Hamman's crunch. Hamman's crunch may occur in 50% to 80% of patients who have pneumomediastinum.7,8,12
Chest x-rays are essential in diagnosing the condition.8 A lateral view is as important as an AP view; a single AP view may miss pneumomediastinum as much as 50% of the time.7 A lateral radiograph better demonstrates retrosternal air, vertical lucent streaks outlining the aorta, and other superior mediastinal structures. Low-grade temperature elevation, mild leukocytosis, and low voltage and axis shifts on electrocardiograms have been reported in cases of pneumomediastinum, but these findings are nonspecific.8
It is critical to exclude other more serious conditions that can accompany pneumomediastinum (see table 1).9,11 This may be done through physical exam and appropriate radiologic studies. A contrast esophagogram is quite useful in assessing for esophageal disruption.9
Treatment. Unless evidence exists for hemodynamic compromise or infection, surgical intervention or catheter drainage is not indicated as therapy. If further sequelae are absent, pneumomediastinum is a self-limiting condition that can be managed with rest, analgesics, and observation. Some argue that this can even be done in an outpatient setting.8,9 Chest pain and mediastinal air usually resolve in 2 to 7 days.9 On recovery, patients need not restrict activity, as recurrence is exceedingly rare.3
In this case, the athlete initially had moderate-to-severe symptoms consistent with a forceful chest contusion. His significant improvement overnight was encouraging. After all other pathologies were ruled out, he was treated symptomatically. Dyspnea and chest pain resolved gradually. The patient was permitted to do progressively more strenuous exercises in the weight room and begin slow skating. His activities advanced as he could tolerate them. One week following the injury, he was able to return to play without further incident.
Dr Curley is an attending physician in the departments of internal medicine and orthopedics and rehabilitation medicine at the Beth Israel Medical Center in New York City. Dr Dorshimer is codirector of the primary care sports medicine fellowship, Dr Bartolozzi is chief of sports medicine and codirector of the primary care sports medicine fellowship, and Dr DeLuca is a clinical assistant professor in the department of orthopedics, all at Pennsylvania Hospital at the University of Pennsylvania in Philadelphia. Address correspondence to Kevin J. Curley, MD, 55 E 34th St, 1st floor, New York, NY 10016; e-mail to [email protected].
Disclosure information: Drs Curley, Dorshimer, Bartolozzi, and DeLuca disclose no significant relationship with any manufacturer of any commercial product mentioned in this article. No drug is mentioned in this article for an unlabeled use.