Introduction:

Endobronchial ultrasound with trans-bronchial needle aspiration (EBUS-TBNA) is an established minimally invasive method of assessing hilar and mediastinal lymphadenopathy for the diagnosis and staging of lung cancer.1 EBUS-TBNA is a relatively benign procedure with a complication rate of 1.44%, the most common being mediastinitis, pneumothorax, and bleeding.2 A rare, but more serious complication is pneumomediastinum, of which few cases are documented in the literature. The most common symptomatology includes persistent cough with chest or neck pain prompting investigation and subsequent discovery of the pneumomediastinum.3 We present a case of a patient with dramatic physical exam findings for pneumomediastinum with progression to life-threatening subcutaneous emphysema that was resolved with a “blowhole” incision.

Case Report:

A 47-year-old woman with a 20 pack-year smoking history, severe chronic obstructive pulmonary disease (COPD) (FEV1 <30%), chronic hypercarbic and hypoxemic respiratory parameters on 3L nasal cannula and BIPAP at night, and recurrent right pneumothorax (PTX) after video-assisted thoracoscopic surgery with pleurodesis presented to clinic for recurrent COPD exacerbations. A chest computed tomography (CT) angiography was performed to evaluate for any underlying pulmonary embolism or bronchiectasis. An interval 3.0 x 2.8 cm right lower lobe (RLL) pulmonary mass was identified. There was stable, but severe centrilobular and paraseptal emphysema with bi-apical scarring. A PET scan showed a hypermetabolic (SUV max 5.9) RLL mass, right hilar lymph node (SUV max 2.2), and several mediastinal lymph nodes.

She underwent a hybrid operating room procedure with EBUS-TBNA and CT-augmented navigational bronchoscopy for biopsy of the lung nodules with fiducial marker placement for later stereotactic body radiation treatment. EBUS with needle aspiration was performed at stations 4R and subcarinal 7 lymph nodes. Slow pull aspiration with gentle needle agitation under ultrasound guidance was done with eight and three aspirations respectively. Additional tissue for molecular studies was obtained from the RLL using navigational bronchoscopy. A bedside cytopathologist confirmed malignant cells, likely adenocarcinoma, present at the 4R lymph node and in the RLL mass. Three fiducial markers were then placed in the mass. The patient tolerated the procedure well and was extubated without complication. A post-procedure chest radiograph (CXR) showed no pneumothorax and the patient was sent to the recovery unit (Figure 1A).

Figure 1: Radiologic and clinical findings of subcutaneous emphysema.

A: Post-bronchoscopy procedure CXR without pneumothorax. B: Four hours post-procedure CXR showing mediastinal and massive supraclavicular subcutaneous emphysema. C: One week outpatient CXR showing partial resolution of subcutaneous emphysema. D: Neck swelling one day after blowhole incision (arrow) in right supraclavicular area. E: Improved neck swelling one week after blowhole incision (arrow) corresponding to CXR panel C.

Approximately four hours post-procedure, the patient’s family reported an acute onset of neck and facial swelling. On physical examination, the patient had bilateral swelling around the neck and face with palpable crepitus and a muffled high-pitched “mickey mouse” voice. Vital signs were stable and lung sounds were diminished, but clear. This was not preceded by coughing and the patient denied chest pain and shortness of breath. An emergent CXR demonstrated subcutaneous emphysema across the entire base of the neck and an area of focal right superior pneumomediastinum without evidence of pneumothorax (Figure 1B). On re-examination fifteen minutes later, the swelling had worsened. A 1 cm “blowhole” incision was made on the right supraclavicular area and subcutaneous air was evacuated (Figure 1D, arrow).

The patient was admitted for observation. A CT thorax was obtained, demonstrating severe pneumomediastinum with subcutaneous emphysema involving the chest and neck without pneumothorax (Figure 2). The following morning, interval decrease in subcutaneous air was noted and the patient reported subjective improvement. Repeat CXR was negative for pneumothorax. Outpatient follow up one week later showed partial resolution of swelling and subcutaneous air (Figure 1C+E).

Figure 2: Computed tomography showing pneumomediastinum and subcutaneous neck emphysema.

A+C: CT-scan at 4R lymph node level with arrow depicting the EBUS FNA needle tract in lung and mediastinal views. B: CT-scan portion showing massive subcutaneous emphysema at the level of the vocal cords with associated high-pitched voice change. D: Upper mediastinum with pneumomediastinum around the trachea and great vessels. Of note, no pneumothorax is seen.

Discussion:

A rare complication of EBUS-TBNA includes pneumomediastinum, however, rapidly progressing subcutaneous emphysema significant enough to lead to airway compromise is exceedingly rare. One previous report describes subcutaneous air post EBUS-TBNA described a patient complaining of neck, face, and chest swelling with chest pain.4 However, there was no respiratory compromise and the patient was conservatively managed with cough suppressants and oxygen.

Our patient did not report any precipitating cough, shortness of breath, chest pain, or neck pain associated with the neck swelling. This is an atypical presentation compared to the majority of documented reports. We believe the initial cause of the pneumomediastinum was likely transient leakage of air during the eight passes taken at the 4R lymph node station. A second potential source is alveolar rupture from the RLL biopsy obtained with navigational bronchoscopy. However, we do not believe this to be the cause as we would expect a pneumothorax. Additionally, we hypothesize that the patient may have performed a Valsalva maneuver while changing clothes, leading to an increase in intrathoracic pressure and worsening the degree of pneumomediastinum and subcutaneous emphysema.

Conclusion:

Respiratory compromise from excessive subcutaneous emphysema following endobronchial procedures is rare, but potentially life-threatening. Thorough pre- and post-operative examinations are critical in recognition of this complication. It is important to note that there are atypical presentations and patients may or may not have prodromal respiratory symptoms. In this case, rapid changes in physical appearance (neck or facial swelling) and changes in voice indicated a pneumomediastinum leading to respiratory compromise. Rapid recognition of this condition is crucial in deciding conservative vs. surgical management. Severe cases of subcutaneous emphysema may be managed with 1-3 cm incisions in the supraclavicular area through the dermis to allow the egress of trapped air. Surgical house officers should do well to keep this technique in their armamentarium.