Cardiovascular Journal of Africa: Vol 26 No 6 (November/December 2015)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 26, No 6, November/December 2015

AFRICA

patients who had pneumomediastinum with similar clinical

symptoms but different causes.

Pneumomediastinum may have varied causes, including

tracheobronchial or oesophageal rupture that may cause an air

leak into the mediastinum.

Pneumomediastinum is a potentially

ominous sign because it may have severe complications. The

differential diagnosis of chest pain, dyspnoea and subcutaneous

emphysemamay include acute pulmonary and cardiac conditions,

such as pericarditis, pulmonary embolism, pneumonia and

pneumothorax, and oesophageal perforation, spasm and reflux

disease. These potential causes may be less likely in patients who

have traumatic or spontaneous pneumomediastinum.

Spontaneous pneumomediastinum is a rare clinical

condition that typically is observed in young men, and

symptoms usually resolve spontaneously after diagnosis.

6,7

Traumatic pneumomediastinum may be accompanied by

subcutaneous emphysema, pneumothorax, rib fractures and

pneumopericardium. Iatrogenic pneumomediastinum may

develop as a result of bronchial or oesophageal rupture during

endoscopy, barotrauma during mechanical ventilation, or after

tracheostomy.

The clinical course of pneumomediastinum is variable.

Patients may have mild complaints or life-threatening respiratory

distress. Patients usually present with chest pain localised to the

sternum. They also may have dysphagia, hoarseness, a foreign

body sensation in the throat, and dyspnoea. Subcutaneous

emphysema detected on physical examination may occur as a

result of the spread of extra-alveolar air to the neck, face and

anterior chest wall. In addition to subcutaneous emphysema,

physical examination may show a crackling sound synchronous

with the heartbeat (Hamman sign), which is pathognomonic for

pneumomediastinum.

Although the reasons for hospital admission were the same

in both patients (chest pain and dyspnoea), the fact that blunt

chest trauma was accompanied by subcutaneous emphysema

in the first case was an important finding in the diagnosis of

pneumomediastinum. Patients who are suspected of having

pneumomediastinum should be evaluated with postero-anterior

and lateral chest radiography that includes the cervical area.

Although CT scan is more sensitive than ordinary chest

radiography in detecting pneumomediastinum, the diagnosis is

often verified with a careful history and chest radiographs.

Radiographs may show a vertical lucent line on the left side

of the heart and aortic arch, lucent line through the retrosternal,

pericardiac and paratracheal areas, or subcutaneous emphysema

of the shoulders and neck.

9-11

Suggestive radiographic signs

may include the thymic sail sign (appearance of thymus as a

triangular sail), ring-around-the-artery sign (lucency along the

right pulmonary artery on the lateral radiograph caused by

mediastinal air), tubular artery sign (air outlining the major

aortic branches), double bronchial wall sign (air outlining the

bronchial wall), continuous diaphragm sign (lucency above the

diaphragm), and extrapleural sign (pulmonary opacity with

oblique margins). The CT scan should be reserved for evaluation

of underlying lung disease or other accompanying conditions.

In the present study, postero-anterior chest radiography was

normal in the first patient, but the second patient had a right

apical pneumothorax and left hyperlucency, with the appearance

of a linear band that suggested the presence of mediastinal air.

Chest radiography may be normal in 30% of patients. Therefore,

the most sensitive method, thoracic CT scan, could be useful in

diagnosing pneumomediastinum when there is clinical suspicion

but non-contributory radiographs. In addition, bronchoscopy

and oesophagoscopy can be considered because they may

show possible ruptures in the bronchial tree and oesophagus

(Boerhaave syndrome); in such cases, surgical intervention

should be considered. In some cases, contrast studies and

mediastinoscopy may be helpful.

In the treatment of pneumomediastinum, supportive

care should be considered when there is no bronchial injury,

oesophageal injury, or bullous structure from lung disease that

may cause air leakage.

The treatment of pneumomediastinum

in the emergency department includes airway and haemodynamic

stabilisation, and treatment to prevent further complications

such as tension pneumomediastinum and mediastinitis. Patients

who have pneumomediastinum should be observed and provided

with supplemental oxygen. Treatment should be non-surgical

until symptoms disappear within four to five days.

12,13

Both of our patients received supportive treatment in the

thoracic surgery department and were followed with daily

postero-anterior chest radiography. They were discharged on

hospital day four and five, respectively, without complications.

Conclusion

Pneumomediastinum is a clinical condition that can vary from a

mild to life-threatening clinical situation. This diagnosis should

be considered for all patients who present to the emergency

department with chest pain and dyspnoea. Pneumomediastinum

also may develop spontaneously or after blunt chest, neck,

facial, or eye injury, with or without tracheal or oesophageal

injury. Despite normal chest radiographs, patients suspected of

having traumatic or spontaneous pneumomediastinum should

have a CT scan. Patients who have pneumomediastinum should

be hospitalised for observation because the condition may be

associated with complications, including death.

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