Spontaneous pneumomediastinum and subcutaneous emphysema in a child with unknown aetiology

Abstract

Spontaneous subcutaneous emphysema and pneumomediastinum in children without any predisposing factors is a rare entity. We present a case of an adolescent boy with spontaneous pneumomediastinum. He is a 14-year-old boy brought to the hospital with an odd feeling in the neck and chest. Initial chest X-ray revealed subcutaneous emphysema and pneumomediastinum. He was further evaluated with CT thorax and abdomen with contrast which revealed extensive pneumomediastinum with associated surgical emphysema in the chest wall and neck. Expert opinions from the cardiothoracic and respiratory teams were obtained. The child was discharged with safety netting and description of red flag signs. Repeat chest X-ray in 2 weeks showed complete resolution of the pneumomediastinum and subcutaneous emphysema. We will briefly discuss about the diagnosis and treatment of spontaneous pneumomediastinum and subcutaneous emphysema.

Background

Pneumomediastinum can be primary or secondary. Spontaneous pneumomediastinum in children is rare and mostly associated with asthma, isolated Valsalva, H1N1 and bacterial infections. We describe this clinical case of spontaneous pneumomediastinum and subcutaneous emphysema with no predisposing factors. The child was treated conservatively.

Case presentation

An adolescent boy was brought by his mother as he had an odd feeling in the neck and chest since mid-morning. The child was fine in the morning going to school, but by mid-morning, he was feeling unwell and by lunch time, mother had to collect him from school. He was then taken to the general practitioner and referred to the hospital. He had felt odd feeling in his neck first, and then the chest and had pain when breathing. His mother noticed mild swelling in the neck and gritty feeling in the neck and right chest wall.

No history of dysphagia.

No history of odynophagia.

No history of change/hoarseness of voice.

No history of cough.

No history of trauma.

No history of fever.

No history of chest pain

No history of palpitations.

No history of abdominal pain or vomiting

No history of inhalational drug intake.

No history of Valsalva manoeuvres like weight lifting, using a balloon pump and occluding the other end, blowing up tight elastic materials.

No significant medical history.

Birth history—nil significant.

Developmental milestones—appropriate for age.

No smoking history.

Examination:

• Airway

  • Patent.
• Breathing

  • Bilateral air entry equal.
  • No added sounds.
  • No chest retractions.
  • Crepitus in the anterior, lateral and posterior chest walls and neck.
• Circulation

  • Peripheries warm and pulses equally felt.
  • Capillary refill time <2 seconds.
• Disability

  • Glasgow Coma Scale 15/15.
  • Bilateral pupils 3 mm equal and reacting.
  • No neck rigidity.
• Exposure

  • No rashes.

Investigations

Blood investigations including full blood count and inflammatory markers were within normal limits. Initial Chest X-ray (figure 1) revealed pneumomediastinum and subcutaneous emphysema but no pneumothorax.

Figure 1.

Chest X-ray revealing pneumomediastinum and subcutaneous emphysema. No pneumothorax. Subcutaneous emphysema is indicated by arrows. PA, postero anterior.

CT thorax and abdomen with contrast (figures 2 and 3) was performed showing extensive pneumomediastinum with associated surgical emphysema in the chest wall and neck. Subtle linear irregularity along the anterior aspect of trachea at about 1:00 position was suspicious of a rent in the tracheal wall.

Figure 2.

CT thorax and abdomen revealing extensive pneumomediastinum with associated surgical emphysema in the chest wall and neck. Subtle linear irregularity along the anterior aspect of the trachea at about 1:00 position was suspicious of a rent in the tracheal wall.

Figure 3.

CT thorax and abdomen (lung window) revealing the subcutaneous emphysema.

Differential diagnosis

Tracheal rupture.

Oesophageal rupture/Boerhaave syndrome.

Necrotising mediastinal infection.

Treatment

Specialist cardiothoracic and respiratory consultations were obtained. The child was sent home and mother counselled to look for warning signs such as difficulty in breathing, chest pain, collapse, cyanosis, palpitations. Safety netting was done.

Outcome and follow-up

Repeat chest X-ray (figure 4) in 2 weeks time showed complete resolution of the pneumomediastinum and subcutaneous emphysema. The child had his peak expiratory flow rate measured twice after the resolution which was normal for his height and age. The asthma predictive index was negative.

Figure 4.

Repeat chest X-ray showing complete resolution of the subcutaneous emphysema and pneumomediastinum.

Discussion

Pneumomediastinum results from the over distention and rupture of the alveoli allowing air to enter the interstitial tissues and extend into the mediastinum, neck and other intra thoracic areas. In severe pneumomediastinum, the air trapping can cause severe obstruction and reduce the cardiac flow. Medline search revealed pneumomediastinum in children with subcutaneous emphysema is rare and is associated with asthma, isolated Valsalva, H1N1, bacterial infections. In our clinical case, there were no predisposing factors and the child had no trauma.

The following paragraph is a brief summary of similar articles published.

A case of spontaneous pneumomediastinum with subcutaneous emphysema in children¹ describes a 7-year-old healthy girl with history of persistent dry cough presenting with spontaneous pneumomediastinum with subcutaneous emphysema. Spontaneous pneumomediastinum in non-asthmatic children with exercise-induced bronchoconstriction² describes two cases of spontaneous pneumomediastinum—one presenting after vigorous exercise and the other with vomiting, coughing aggressively. Spontaneous pneumomediastinum: a rare disease associated with chest pain in adolescents³ analyses the clinical characteristics of SPM (Spontaneous Pneumomediastinum) in adolescents and the diagnostic implications of CT and esophagography therein. Spontaneous pneumomediastinum in H1N1 infection⁴ describes a case presenting with spontaneous pneumomediastinum after an H1N1 infection. Spontaneous pneumomediastinum and subcutaneous emphysema as a complication of asthma in children: case report and literature review⁵ describes a 10-year-old girl with asthma presenting with subcutaneous emphysema and spontaneous pneumomediastinum and literature review of various cases across the world. Spontaneous pneumomediastinum in the paediatric patient⁶: a total of 129 patients were included. Review of children with pneumomediastinum treated from January 2011 to October 2014. Primary (no precipitating factors) and secondary (underlying respiratory disease) SPM patients were included. Admission data and clinical outcomes were recorded. Spontaneous pneumomediastinum with subcutaneous emphysema: report of two paediatric cases⁷—they present two children diagnosed with spontaneous pneumomediastinum. The first case is a 9-year-old boy who developed neck pain with a history of poorly controlled asthma and recently diagnosed right middle lobe pneumonia. The second case is a 14-year-old boy who developed chest pain with a history of cough and congestion for four days. Spontaneous pneumomediastinum analysis of 87 paediatric patients⁸ analyses 87 paediatric patients with SPM. The common causes of secondary SPM were asthmatic exacerbation, pneumonia or lower respiratory tract infections, or choking. Teenager with chest pain and swollen neck: a leave-it-alone condition⁹ describes a 19 year old with subcutaneous emphysema pneumomediastinum and air in the epidural space. The patient was treated conservatively. Three different cases of spontaneous pneumomediastinum were described by Lee et al.¹⁰

Learning points.

• Spontaneous pneumomediastinum and subcutaneous emphysema in children is a rare entity.

• When a child presents to the emergency department with the symptoms, after a thorough history and clinical examination, an initial chest X-ray is recommended to rule out consolidation, pneumomediastinum and subcutaneous emphysema. Blood tests including full blood count to rule out infections and absolute eosinophil count to rule out allergic response are suggested.

• CT scan of the thorax and abdomen performed to rule out tracheal rent and Boerhaave syndrome.

• If no cause is demonstrated, then the patient should be treated conservatively with repeat chest X-ray in 2 weeks. Bronchoscopy may be beneficial, oesophagogastroduodenoscopy and water soluble contrast to be considered to look for a tear in the oesophagus.