Revista Adolescência e Saúde

Revista Oficial do Núcleo de Estudos da Saúde do Adolescente / UERJ

NESA Publicação oficial
ISSN: 2177-5281 (Online)

Vol. 14 nº 4 - Oct/Dec - 2017

Case Report Imprimir 

Páginas 210 a 216

Spontaneous pneumomediatinum - when the rare also happens

Neumomediastino espontáneo - cuando lo raro también acontece

Pneumomediastino espontâneo - quando o raro também acontece

Autores: Joana Isabel da Silva Ferreira1; Marta Sofia Faria Alves2; Alícia Raquel Moreira Rebelo3; Sofia Madureira Vasconcelos Lopes4; Cristina Maria Gonçalves Ferreira5; Andreia Manuela Tavares Castro Lopes6

1. Internal of Specific Training of Medical Pediatrics of the Pediatric Service of the Hospital of Senhora da Oliveira. Guimarães, AC, Portugal
2. Internal of Specific Training of Medical Pediatrics of the Pediatric Service of the Hospital of Senhora da Oliveira. Guimarães, AC, Portugal
3. Internal of Specific Training of Medical Pediatrics of the Pediatric Service of the Hospital of Senhora da Oliveira. Guimarães, AC, Portugal
4. Internal of Specific Training of Medical Pediatrics of the Pediatric Service of the Hospital of Senhora da Oliveira. Guimarães, AC, Portugal
5. Cristina Maria Gonçalves Ferreira: Pediatric Assistant of the Pediatrics Department of the Hospital Senhora da Oliveira - Guimarães. Guimarães, AC, Portugal
6. Andreia Manuela Tavares Castro Lopes: Hospital Assistant of Pediatrics of the Pediatric Service of the Hospital of Senhora da Oliveira. Guimarães, AC, Portugal

Joana Isabel da Silva Ferreira
Hospital da Senhora da Oliveira - Guimarães
Rua dos Cutileiros, 114, Creixomil
Guimarães, Portugal. CEP: 04835-044

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How to cite this article

Keywords: Chest pain, subcutaneous emphysema, mediastinal emphysema.
Palabra Clave: Dolor en el pecho, enfisema subcutáneo, enfisema mediastínico.
Descritores: Dor no peito, enfisema subcutâneo, enfisema mediastínico.

OBJECTIVE: Report a case of a teenager with spontaneous pneumomediastinum.
CASE DESCRIPTION: A fifteen-year-old boy, smoker, with no history of trauma or known lung disease admitted to the emergency room with sudden thoracic pain onset during an exercise, worsened by deep breath and local pressure. Physical examination showed subcutaneous crepitations to palpation of the cervical and supraclavicular region. Complementary exams confirmed the diagnosis of spontaneous pneumomediastinum, and underwent symptomatic treatment with a favorable clinical evolution.
COMMENTS: Spontaneous pneumomediastinum is a rare condition in pediatric age, more prevalent in young males and presents with a nonspecific symptom requiring a high level of suspicion to the correct diagnosis. Treatment is symptomatic supportive and the course is usually benign.

OBJETIVO: Presentar el caso clínico de un adolescente con neumomediastino espontáneo.
DESCRIPCIÓN DEL CASO: Adolescente de quince años, del sexo masculino, fumante, sin historia de trauma o enfermedad pulmonar conocida, admitido en el Servicio de Urgencia con dolor torácico retroesternal de inicio súbito durante la realización de un ejercicio, agravado por inspiración profunda y presión local. Al examen físico presentaba crepitaciones subcutáneas a la palpación de la región cervical y supraclavicular. Los exámenes complementarios confirmaron el diagnóstico de neumomediastino espontáneo, habiendo realizado tratamiento sintomático con evolución clínica favorable.
COMENTARIOS: El neumomediastino espontáneo es una entidad rara en edad pediátrica, más prevalente en jóvenes y que se manifiesta por un síntoma inespecífico, siendo necesario un alto nivel de sospecha para el diagnóstico correcto. El tratamiento es sintomático y el curso es generalmente benigno.

OBJETIVO: Apresentar o caso clínico de um adolescente com pneumomediastino espontâneo.
DESCRIÇÃO DO CASO: Adolescente de quinze anos, do sexo masculino, fumante, sem história de trauma ou doença pulmonar conhecida, admitido no Serviço de Urgência com dor torácica retroesternal de início súbito durante a realização de um exercício, agravada pela inspiração profunda e pressão local. Ao exame físico apresentava crepitações subcutâneas à palpação da região cervical e supraclavicular. Os exames complementares confirmaram o diagnóstico de pneumomediastino espontâneo, tendo realizado tratamento sintomático com evolução clínica favorável.
COMENTÁRIOS: O pneumomediastino espontâneo é uma entidade rara em idade pediátrica, mais prevalente em rapazes e que se manifesta por um sintoma inespecífico sendo necessário um elevado nível de suspeição para o diagnóstico correto. O tratamento é sintomático e o curso é geralmente benigno.


Spontaneous pneumomediatinum (PE) is a rare pediatric syndrome, first described by Hamman in 19391. It is defined by the presence of free air in the mediastinum, with no associated traumatic cause. It is more frequent in long individuals, male and usually has a benign course2,3,4. The exact incidence is not known, since it is believed that there are underdiagnosed cases, varying from 1 in 800 to 1 in 42,000 of hospital admissions (adults and children)4,5. The classic clinical triad consists of chest pain, dyspnea, and subcutaneous emphysema. However, it remains a diagnosis of exclusion, and secondary causes that represent greater severity should be investigated. Complications are rare and are usually related to the underlying pathology. Most cases are benign and self-limiting.


A 15-year-old male, Caucasian, smoker (0.4 liters / year), without usual medication and no personal history or family history of disease (namely pulmonary disease). He applied to the Urgency Service for chest pain retrosternal with 5 hours of evolution. This had a sudden onset during the pre-training soccer warm-up exercise, aggravated by deep inspiration and local pressure, without irradiation. He denied other complaints, namely cough, rhinorrhea or fever. The adolescent also reported that he had no recent infectious intercurrences, contact with ill people, trauma or use of illicit drugs.

Physical examination was hemodynamically stable, without fever, with peripheral saturations of oxygen in ambient air of 99-100% with periods of desaturation in the supine position up to 93-94%, but with spontaneous recovery. It was sweaty and the palpation of the cervical and supraclavicular region showed subcutaneous crackles. He did not present dyspnea or cyanosis, although he was more uncomfortable in the supine position. Pulmonary auscultation revealed a vesicular murmur, somewhat diminished, but symmetrical and without adventitious noises. The rest of the examination was normal.

An electrocardiogram was performed that showed no changes. The analytical study, which included cardiac enzymes (creatine phosphokinase MB fraction, myoglobin and troponin I), was normal and the study of drugs of abuse in the urine was negative. Postoperitoneal (chest X-ray) radiography confirmed the presence of free air in the mediastinum (figure 1). Concomitant pneumothorax or pleural effusion was not observed.

Figure 1. Chest X-ray PA: hypotransparent line that delineates the cardiac silhouette showing the pleura (black arrows); hypertransparent image bypassing the aortic button with extension to the anterior face of the heart (circles); hypertransparent line above the diaphragm (continuous diaphragm signal) (gray arrow); Bilateral supraclavicular subcutaneous emphysema (white arrows).

For better elucidation and also to assess the extent of disseminated air and to exclude underlying pulmonary pathology, a CT scan of the chest was performed, where the diagnosis was more evident, which revealed no alterations other than those already documented in the study. chest X-ray (figure 2).

Figure 2. CT of the thorax: Pneumomediatinum separating the structures of the mediastinum (black arrows) and subcutaneous emphysema reaching the axillae (white arrow). There are no signs of pneumothorax or pleural effusion. There are no changes in the parenchyma. Threads without expansive lesions. In the mediastinum the airways are permeable and the great vessels with normal path and caliber.

The patient was then admitted for surveillance, with cardiorespiratory monitoring and symptomatic treatment (rest, analgesia and oxygen therapy at high throughput). His evolution was favorable, being that at the second day of hospitalization he was asymptomatic and without alterations to the objective examination. On the fourth day of hospitalization, chest X-ray showed complete resolution of pneumomediatinum and subcutaneous emphysema (figure 3). The adolescent was discharged to the home, oriented for consultation and with indications for smoking cessation.

Figure 3. X-ray of the thorax PA on the fourth day of hospitalization showing complete resorption of pneumomediatinum and subcutaneous emphysema.


PE is a rare condition that occurs in children or adolescents with no associated traumatic cause and is manifested by a non-specific symptom and a high level of suspicion is necessary for the correct diagnosis. The incidence is bimodal with an initial peak in childhood and pre-age and a second in adolescence 5.

PE may be primary or secondary, through the absence or presence of underlying pathology. Most cases are secondary to respiratory diseases 5-7 . Treatment and prognosis of primary or secondary PE is similar.

Potential sources of free air in the mediastinum may be intrathoracic (trachea, bronchi, esophagus, lung, pleural space) or extra thoracic (head, neck, peritoneum) 8 . The most widely accepted explanation is based on the "Macklin effect", which states that increased intra-alveolar pressure leads to rupture of the terminal alveoli, with the consequent extravasation of free air from the bronchovascular space to the mediastinum 9,10 . The air can also spread to the subcutaneous tissue, pleural, pericardial and / or peritoneum, which translates clinically by subcutaneous emphysema, pneumothorax, and pneumopericardium pneumoperitoneum, 6 respectively.

The classical triad is characterized by chest pain (typically retrosternal and pleuritic features), dyspnea and subcutaneous emphysema (usually in the anterior cervical region). The latter, when present, allows to assume the diagnosis 2 .The auscultation of synchronous crackling with heart beats ( Hamman's signal ) is classically described as pathognomonic, however it is infrequent or difficult to perceive (10 to 20% of cases) 2,3 . Other possible symptoms are cough, fever, dysphonia, dysphagia, and odynophagia (Table 1 - clinical findings). In more than 30% of patients with uncomplicated PE the physical examination is normal 5 .

Chest x-ray (AP and profile) is the method generally sufficient for diagnosis, with several radiographic signs described that are suggestive of PE 4,5,11 (Table 1 - imaging findings). Chest CT is only recommended for diagnostic doubt, although it is considered the gold standard in the detection of air in the mediastinum, in addition to diagnosing concomitant parenchymal and pleural changes1,3,5,11. Other tests should be guided by diagnostic suspicion6. Thoracic ultrasound may be advantageous, but diagnostic criteria are not well established and the utility of the technique is limited in patients with pulmonary hyperinflation. The electrocardiogram (ECG) may show several changes according to the existence of associated pneumopericardium, but the exact mechanism of these changes is unknown5.

The analytical study often reveals leukocytosis and / or neutrophilia with elevation of C-reactive protein5, but generally these findings are more associated with the presence of underlying infection than with the pneumomediatinum itself.

The main differential diagnoses include a series of clinical conditions that present with acute precordial pain, namely acute coronary syndrome, pericarditis, pneumothorax, pulmonary embolism, perforation of the tracheobronchial tree and spontaneous perforation of the esophagus (Boerhaave Syndrome). In this, patients usually present with more hypotension and shock than those with PE.

In the literature there is some confusion in the distinction between predisposing and precipitating factors . The former concern preconditions that favor the occurrence of pneumomediatinum (like asthma, lung disease, inhaled drug use, smoking, corticosteroids), while the latter are events closely related to the development of the condition, as they usually trigger an increase (vomiting, coughing, exacerbation of asthma, defecation, physical exercise, upper respiratory tract infection, use of inhaled drugs) (Table 2).

In this case, we hypothesized that smoking may have been an important predisposing factor. The local inflammatory response, increased secretion of mucus, and bronchoconstriction triggered by tobacco, associated with Valsalva maneuvers during coughing, lead to an increase in intra-alveolar pressure in the obstructed areas facilitating alveolar rupture. Therefore, smokers are a known risk group, but the smoking limit associated with increased risk is not established.

Therapy, in the absence of complications, consists of rest, analgesia and avoidance of risk factors. Oxygen therapy has been used, but some authors consider that it will only be necessary in severe cases with respiratory insufficiency, because most cases of PE resolve spontaneously4,5. Complications are rare, usually related to the underlying pathology. One that requires special care is the tension pneumomediatinum, since it is associated with compression of vascular structures and central airways with obstructive syndrome and hemodynamic instability that put the patient at risk of life2.5.

Most of the time, however, EP evolution is favorable with spontaneous resolution in 2 to 15 days4,5. Recurrences are also rare (less than 5% of cases) 5 , benign and usually occur when exposure to the predisposing factor remains (like tobacco) or can´t be avoided (like asthma). Isolated PE does not require follow-up.

This case shares several aspects with most of those mentioned in the literature, namely in the form of presentation, therapeutic approach and clinical evolution.


Spontaneous pneumomediatinum is a rare and usually benign condition. Clinic allied to chest radiography is usually sufficient for diagnosis. The treatment is symptomatic and depends on the existence or not of complications. The identification and correction of possible triggering factors is important in trying to avoid complications and relapses.


1. Hamman L. Spontaneous mediastinal emphysema. Bull Johns Hopkins Hosp 1939; 64:1-21.

2. Avaro JP, D'Journo XB, Hery G, Marghli A, Doddoli C, Peloni JM, Miltgen J, Bonnet D. Pneumomédiastin spontané du jeune adulte: une entité clinique bénigne. Rev Mal Respir 2006 Feb;23(1 Pt 1):79-82.

3. Bodart E, Bilderling G de, Nisolle J.F., Trigaux J.P., Tuerlinckx D. Pneumomédiastin spontané chez un adolescent: une cause sous-estimée de douleurs thoraciques. Arch Pédiatr 1999;6:1293-6.

4. Chalumeau M, Le Clainche L, Sayeg N, Sannier N, Michel JL, Marianowski R, Jouvet P, Scheinmann P, de Blic J. Spontaneous pneumomediastinum in children. Pediatr Pulmonol 2001 Jan;31(1):67-75.

5. Ammar A Saadoon, Ibrahim A Janahi. Spontaneous pneumomediastinum in children and adolescents. Outubro 2016. [Aceito em 29 de Outubro de 2016]. Disponível em:

6. Semedo FHMA, Silva RS, Pereira S, Alfaiate T, Costa T, Fernandez P et al. Pneumomediastino espontâneo: relato de um caso. Rev Assoc Med Bras 2012; 58(3):355-7.

7. Kelly S, Hughes S, Nixon S, Paterson-Brown S. Spontaneous pneumomediastinum (Hamman's syndrome). The Surgeon 2010;8:63e6 Chapter 72.

8. Zylak CM, Standen JR, Barnes GR, Zylak CJ. Pneumomediastinum revisited. Radio Graphics 2000;20:1043e57.

9. Romero and Trujillo. Macklin effect in asthma exacerbation. Spontaneous pneumomediastinum and subcutaneous emphysema in asthma exacerbation: The Macklin effect. Heart Lung 2010. 39:444-7.

10. Macklin M, Macklin C. Malignant interstitial emphysema of the lungs and mediastinum as an important occult complication in many respiratory diseases and other conditions: interpretation of the clinical literature in the light of laboratory experiment. Medicine 1944; 23:281e358.

11. Chen IC, Tseng CM, Hsu JH, Wu JR, Dai ZK. Spontaneuos pneumomediastinum in adolescents and children. Kaohsiung J Med Sci 2010 Feb;26 : 84-8
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