A 6-year-old boy is brought to the emergency department by his mother due to new-onset chest pain. A week ago, he developed a low-grade fever with nasal congestion and a dry cough. Over the past few days, he has had paroxysms of coughing that seem to be worse at night. Last night, the patient developed pain in his chest that did not improve after he was given acetaminophen. He has no chronic medical conditions and takes no daily medications. Temperature is 37.3 C (99.1 F), blood pressure is 106/76 mm Hg, pulse is 130/min, respirations are 36/min, and pulse oximetry is 98% on room air. There is clear rhinorrhea. The posterior oropharynx and tonsils are erythematous. There is mild swelling of the neck and crepitus over the anterior chest. Pulmonary examination reveals clear and equal breath sounds bilaterally. Cardiac examination shows a normal S1 and S2 with no murmurs, rubs, or gallops. Which of the following is the best next step in evaluation of this patient?
Spontaneous pneumomediastinum | |
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This patient has subcutaneous emphysema over the chest consistent with spontaneous pneumomediastinum (SPM). High intraalveolar pressure due to severe coughing paroxysms can cause air to leak from the chest wall into subcutaneous tissues. Children who cough due to asthma or a respiratory infection are at increased risk for SPM, as are tall, thin adolescent boys.
Presentation often involves acute chest pain and/or shortness of breath. On examination, subcutaneous emphysema is typically palpated in the neck or precordial areas. A crunching sound may be heard over the precordium (Hamman sign). In rare cases, spontaneous pneumothorax (air in the pleural space) can accompany SPM and present with diminished breath sounds on the affected side.
The first step in evaluation is chest x-ray to confirm the presence of mediastinal gas and rule out a life-threatening pneumothorax that may require emergency needle thoracostomy. An uncomplicated SPM can be managed with rest, pain control, and avoidance of maneuvers that increase pulmonary pressure (eg, Valsalva). Symptoms typically resolve within days to weeks.
(Choice A) Bronchoscopy is used to identify an aspirated foreign body, which may precipitate pneumomediastinum. Foreign body aspiration presents with cough, wheezing, and diminished breath sounds, not rhinorrhea, congestion, and fever, as in this patient.
(Choice C) Contrast esophagography is used to evaluate for esophageal rupture, a rare cause of pneumomediastinum in patients with difficulty swallowing and a history of forceful vomiting, neither of which is seen in this patient.
(Choice D) Pulmonary function tests (PFTs) can help to diagnose asthma, which is a risk factor for SPM. However, PFTs are contraindicated with SPM because forced expiration increases pulmonary pressure, worsening the air leak.
(Choice E) Throat culture is used to diagnose bacterial pharyngitis, which presents with fever and sore throat. This patient's rhinorrhea and congestion make a viral infection more likely. Chest x-ray is the priority.
Educational objective:
Severe coughing paroxysms can increase intraalveolar pressure and cause air to leak into subcutaneous tissues (ie, subcutaneous emphysema), resulting in spontaneous pneumomediastinum. The first step in management is chest x-ray to confirm the diagnosis and rule out pneumothorax.