CASE 15352 Published on 17.12.2017

Atypical chest pain caused by spontaneous pneumomediastinum

Section

Chest imaging

Case Type

Clinical Cases

Authors

Gasim Ahmed, Aneeq Ahmed, Sami Nour, Mudathir Mohamed

University Hospital Limerick; St Nessan Road v94f858 Limerick, Ireland; Email:gasimsalaheldin@yahoo.com
Patient

17 years, male

Categories
Area of Interest Education, Cardiac, Thorax, Oesophagus ; Imaging Technique Digital radiography, CT, Conventional radiography, Fluoroscopy
Clinical History
A 17-year-old male patient with no past medical history presented with a 24-hour history chest pain radiating to the anterior aspect of the neck. Physical examination revealed normal vital signs. Swelling and crepitus involving the bilateral anterolateral aspects of the neck and the submandibular fossae were noted.
Imaging Findings
A chest X-ray, in addition to pneumomediastinum and pneumopericardium, revealed supraclavicular, para-tracheal and infrahyoid emphysema. A computed tomography of the thorax showed pneumopericardium with air dissecting from the diaphragm crus through the posterior, middle, anterior and superior mediastinum. There was also diffuse bilateral supra-clavicular, pre-tracheal, carotid, posterior cervical, retro-pharyngeal space and bilateral axillary surgical emphysema. No parenchymal lung disease was detected. A water soluble contrast fluoroscopic examination of the oesophagus revealed no evidence of extravasation or leak of contrast.
Discussion
Background:
Spontaneous pneumomediastinum is the presence of air within mediastinum structures. The condition is considered rare with a reported incidence of 1/42, 000 of admissions [1]. Spontaneous pneumomediastinum has been recognised at least since 1819 but it was Hamman who initially reported a case series in 1937 and revisited the disease in 1939 [1-3]. Physiopathology is related to alveolar rupture and gas dissection through the bronchovascular fascia followed by pulmonary interstitial dissemination to the mediastinum as described by Macklin in 1939 [4].

Clinical Perspective:
Chest pain, the predominant presenting feature affecting 55% of patients, is typically retrosternal and may have a pleuritic character. Dyspnoea, cough and neck pain occur in 40%, 32%, and 17% of patients, respectively [5, 6]. Subcutaneous emphysema may complicate 60% of cases [7, 8]. Hamman's sign, a crunching, rasping sound, synchronous with systole may be present in 50% of patients [3, 8]. The disease can be either primary or secondary to trauma. Other triggers include coughing, balloon inflation, aviation, vomiting, and oesophageal rupture [9, 10, 11, 12]. The role of cocaine has also been described [13]. In the paediatric cohort, acute asthma exacerbation [7, 14] and lower respiratory tract infections are the predominant causes [7, 14-16]. In 21% of cases no cause is found [17].

Radiological Perspective:
Radiologically, a number of signs such as the Naclerio's V sign, V sign at confluence of brachiocephalic veins and ring-around-the-artery sign can be observed as lucent streaks of gas outline mediastinal structures [18]. Additional signs include tubular artery, double bronchial wall and haystack signs. Other abnormalities such as pneumothorax, pleural effusion (which may indicate oesophageal rupture), and signs of chronic lung disease may be noted. Computed tomography is usually not indicated unless in patients with underlying lung disease. Contrast oesophagography is helpful if oesophageal rupture is suspected as a cause.

Outcome:
The management of uncomplicated spontaneous pneumomediastinum is conservative and includes analgesia, rest, oxygen, and avoidance of manoeuvres that increase pulmonary pressure. Although evidence is limited, air travel is usually permitted two weeks after radiographic resolution. In cases with complications such as pneumothorax, management should target the specific complication. The natural history of the disease is benign. Although approximately 5% of cases may recur, the outcome is favarouble [19].

Take Home Message:
Spontaneous pneumomediastinum is a rare, generally benign cause of chest pain.

Radiologically, streaks of air are observed outlining mediastinal structures.

In one fifths of cases no trigger is identified.
Differential Diagnosis List
Primary spontaneous pneumomediastinum
Medial pneumothorax
Pneumopericardium
Pneumoperitoneum
Final Diagnosis
Primary spontaneous pneumomediastinum
Case information
URL: https://www.eurorad.org/case/15352
DOI: 10.1594/EURORAD/CASE.15352
ISSN: 1563-4086
License