Maj James D. Leiber, DO; Capt Nghia T. Phan, DO

THE PHYSICIAN AND SPORTSMEDICINE - VOL 33 - NO. 8 - AUGUST 2005

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In Brief: Pneumomediastinum is a rare injury that has been documented in both recreational and competitive athletes. It has been reported in a variety of situations, but it is often a result of chest trauma. Repeated and prolonged use of Valsalva's maneuvers is also believed to lead to pneumomediastinum, as was the case with the synchronized swimmer presented here. The condition is self-limited and benign in healthy patients, and oxygen therapy may be helpful. Recommendations for athletes typically promote a gradual return to activity after 7 to 10 days.

Pneumomediastinum is the presence of air in the mediastinal tissues. The pathologist R. T. H. Laënnec first described the condition in 1819 in trauma patients. In pneumomediastinum, the air can come from alveolar, bronchial, or esophageal rupture; such injuries in adults may result from positive-pressure ventilation, trauma, or underlying lung disease.^1-3 The sudden increase in pressure against the closed glottis that results from blunt chest trauma likely causes increased pressure in the alveoli, which may lead to rupture, causing an air leak.

Pneumomediastinum can also be spontaneous, as described by Hamman in 1939. Spontaneous pneumomediastinum (SPM) is defined as pneumomediastinum that does not occur in a setting of gross trauma or positive-pressure ventilation.^1,4 Valsalva's maneuvers have been described as the cause of SPM in a number of cases (eg, coughing, drug use, exercise, childbirth).^1,2 Although SPM is rare in children, its most common medical causes are asthma exacerbation and infections.²

However, in healthy young people with SPM, the cause is often a transient increase in intrathoracic pressure (Valsalva's maneuver) that occurs in sports. According to one literature review, SPM has been reported in skiing, snowboarding, tubing and sledding, bicycling, scuba diving, kayaking, tennis, equestrian activities, contact sports, and running. Most of these injuries were caused by direct, blunt trauma to the chest.^5-8 In our case, we describe SPM in a synchronized swimmer, which we believe has not been reported in the medical literature.

A variety of traumatic and overuse injuries have been sporadically associated with synchronized swimming. However, a recent Medline search using keywords such as subcutaneous emphysema, pneumomediastinum, mediastinal emphysema, sports, swimming, diving, and synchronized swimming produced no reports of pneumomediastinum related to synchronized swimming.

Case Report

History. A 12-year-old girl who had competed as a synchronized swimmer for the previous 2 years described in the emergency department a 5-day history of sore throat and a 1-day history of neck pain associated with movement and palpation. She also noted a globus sensation during swallowing. The patient reported that she felt like she had "pulled something" in her neck while practicing in the pool on the evening prior to presentation. This sensation was followed by mild tenderness and a "crackling" sound in the neck region. On the morning of presentation, the neck pain had progressed and the crackling had spread to the back of her head and part of her left shoulder.

The patient did not have fever, chills, nausea, vomiting, cough, or dyspnea. She reported that she had been training more during the last few weeks to prepare for an upcoming competition. Her medical and surgical history was unremarkable. She had no known allergies and was not taking any medication.

Physical exam. Her vital signs were: blood pressure, 109/48 mm Hg; respiratory rate, 22/min; heart rate, 89/min; and oxygen saturation of 100%. She was afebrile. Her exam was remarkable for subcutaneous crepitus along the trachea, base of the head, left neck, and shoulder. These areas were tender to palpation. Her throat was clear, without erythema or exudates.

Diagnosis. X-rays of the chest and soft tissues of the neck confirmed pneumomediastinum and subcutaneous emphysema. Computed tomography (CT) (figures 1 and 2) indicated subcutaneous emphysema and posterior pharyngeal air. CT did not show a retropharyngeal abscess or other source of infection.

Treatment. The patient was admitted for observation and oxygen therapy. Her symptoms were significantly improved by evening, when only a small part of her left sternocleidomastoid region had crepitus. She had only very mild tenderness to palpation. By the next morning, the subcutaneous emphysema had completely resolved. A chest radiograph showed improvement of the pneumomediastinum. A follow-up radiograph 2 weeks later showed complete resolution.

Discussion

Pneumomediastinum is most commonly seen in critically ill patients put on mechanical ventilation after they sustain barotrauma.^1,2,5 In pediatric medicine, it is commonly seen in patients with asthma.² The pathogenesis of pneumomediastinum is often described as a ruptured perivascular alveolar wall resulting from increased intrathoracic pressure. Air may then dissect along the bronchovascular sheaths toward the mediastinal soft tissue and then toward the neck and subcutaneous tissue.^3,5

The diagnosis is typically made using a combination of the patient's history, physical exam, and radiologic information. A patient should get a chest x-ray if he or she complains of any combination of acute pleuritic chest pain, neck pain, torticollis, dyspnea, or dysphagia and a physical exam shows evidence of subcutaneous emphysema in the setting of an exposure to increased intrathoracic pressure. The chest x-ray should confirm the clinical suspicion of the presence of mediastinal air.⁹

In this case, CT was obtained in the emergency department to rule out the possibility of a retropharyngeal abscess. The images, although unnecessary for the ultimate diagnosis, clearly show the evidence of mediastinal air.

Synchronized Swimming Risks

The complexity and technical precision of synchronized swimming place great physical demands on athletes. The sport evolved in the early 1900s and became an Olympic event in 1984. Formally recognized programs exist in 59 countries. The highly competitive nature of synchronized swimming, coupled with its immense physical challenges, necessitates long, vigorous training sessions. Its mandatory technical elements are designed to illustrate the athlete's flexibility, strength, skill, power, and control. Typical musculoskeletal overuse injuries have been reported.¹⁰

Lung capacity may be the most important physical quality in this sport. As part of their intensive training, athletes often perform vigorous exercises for prolonged periods while holding their breath. Competitive athletes normally train 6 days per week, with each session lasting 3 to 5 hours.^10,11 The repetitive and prolonged breath-holding required of athletes while they perform demanding exercises can increase intrathoracic pressure enough to cause pneumomediastinum, as illustrated in this case report. The exact frequency of this complication has not been reported.

Treatment Issues

The natural history of SPM in healthy people is self-limited and benign.¹ Most cases of SPM can be treated expectantly. Observation for 24 hours has been recommended to monitor for worsening symptoms or development of a pneumothorax. The use of oxygen therapy may be reserved for more severe cases in which the patient is symptomatic, has large amounts of air noted on radiographs or a coexisting pneumothorax, or has other chronic comorbidities.¹²

Oxygen therapy may quicken the resolution of symptoms.⁸ Oxygen therapy is thought to create an environment of nitrogen washout. When oxygen is inspired, a gradient develops between the nitrogen-rich interstitium and the low nitrogen level in the tracheobronchial air. This gradient facilitates the resorption back into the tracheobronchial tree.

In two studies of SPM in pediatric patients,^2,4 no children experienced any complications from SPM, including subjects whose SPM was induced by asthma, cough, or emesis. Some of these patients also had small pneumothoraces that did not require intervention. Most were admitted for observation, bed rest, and analgesic therapy. Patients with asthma were also treated with bronchodilators and steroids as indicated.³ No adverse, long-term sequelae from uncomplicated SPM in a healthy person have been documented.^1,6

Return to Play

There are no evidence-based medical guidelines for return-to-play determinations following sports-related pneumomediastinum. Resolution is quick, ranging from 4 to 10 days, and recurrence rates are low. One source¹³ recommends allowing an asymptomatic athlete to slowly resume full activity in 7 to 10 days. A follow-up chest radiograph to verify resolution of SPM and to definitively rule out any underlying pathology should be considered.¹³ Although not necessarily based on evidence, it has been recommended that patients avoid air travel for 3 to 4 weeks after complete resolution of sports-related pneumothorax.¹⁴ In the absence of any data to the contrary, it is reasonable to adopt a similar recommendation for sports-related pneumomediastinum as well.

Look Below the Surface

SPM is a rare but disruptive complication in young, healthy athletes. Fortunately, when SPM does occur, it is self-limited and requires little, if any, intervention. Furthermore, there is no evidence of long-term sequelae.

This article provides an example of pneumomediastinum and subcutaneous emphysema in an athlete who performed repetitive and prolonged Valsalva's maneuvers. Her case highlights the need for additional surveillance of athletes, as well as research of injuries sustained in the increasingly popular sport of synchronized swimming. Primary care and sports medicine physicians should consider SPM when an athlete with sports-related exposure to increased intrathoracic pressures reports a sore throat, neck pain, and dysphagia and does not have other symptoms of an upper respiratory infection.

The opinions or assertions contained in this article are the views of the authors and should not be construed as official or reflecting the views of the United States Air Force or the Department of Defense.

References

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10. Mountjoy M: The basics of synchronized swimming and its injuries. Clin Sports Med 1999;18(2):321-336
11. Chu DA: Athletic training issues in synchronized swimming. Clin Sports Med 1999;18(2):437-445
12. Weissberg D, Weissberg D: Spontaneous mediastinal emphysema. Eur J Cardiothorac Surg 2004;26(5):885-888
13. Ferro RT, McKeag DB: Neck pain and dyspnea in a swimmer: spontaneous pneumomediastinum presentation and return-to-play considerations. Phys Sportsmed 1999;27(10):67-71
14. Soundappan SV, Holland AJ, Browne G: Sports-related pneumothorax in children. Pediatr Emerg Care 2005;21(4):259-260

Dr Leiber is a full-time faculty member at the Malcolm Grow Medical Center Family Medicine Residency at Andrews Air Force Base in Maryland. Dr Phan is a family physician at Mike O'Callaghan Federal Hospital at Nellis Air Force Base in Nevada. Address correspondence to James D. Leiber, DO, 1075 W Perimeter Rd, Andrews Air Force Base, MD 20762; e-mail to james.leiber@andrews.af.mil.

Disclosure information: Drs Leiber and Phan 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.