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Abstract
A 72-year-old female patient underwent endobronchial ultrasound and transbronchial needle aspirate sampling of mediastinal lymph nodes to investigate a middle lobe abnormality following an urgent referral. CT imaging completed the following day demonstrated a pneumomediastinum. At clinical review, the patient remained clinically stable and no intervention was required.
- respiratory medicine
- pneumomediastinum
- respiratory cancer
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Background
Pneumomediastinum is a rare condition, whereby there is free air within the mediastinum. There are a myriad of causes including barotrauma from raised intrathoracic pressure, infection, idiopathic and iatrogenic (after instrumentation of the mediastinum). We describe a pneumomediastinum following EBUS TBNA sampling—something that is scarcely reported in the literature.
Case presentation
A 72-year-old female patient was referred to the respiratory team on an urgent basis after a chest X-ray had demonstrated a middle lobe collapse. The chest X-ray had been undertaken to investigate a new cough.
The patients’ previous medical history included asthma, obesity, ocular hypertension and osteoarthritis. The patient was a recent ex-smoker (6 weeks abstinence) and had accrued a 60-pack year history.
The patient described no relevant respiratory or systemic symptoms.
Clinical examination revealed a mild, global end expiratory wheeze in the chest but no other abnormality.
Investigations
The patient underwent an EBUS TBNA examination due to the middle lobe collapse on chest X-ray. Endobronchial inspection was normal, but enlarged hilar lymph nodes were identified on ultrasound view. Samples were obtained from mediastinal lymph node station 11R using a 21-gauge needle. Two highly experienced bronchoscopists carried out the procedure. The patient was under conscious sedation using a combination of fentanyl and midazolam. One per cent lidocaine was administered via the bronchoscope to achieve local anaesthesia. It was uneventful and there were no recorded complications.
The patient underwent CT chest and upper abdomen 24 hours after the EBUS TBNA as part of workup for possible bronchogenic malignancy. This showed extensive pneumomediastinum, tracking superiorly into the neck and anterior chest wall (figure 1A–C). There was no evident aetiology for the pneumomediastinum seen on CT imaging. There was no mass or appreciably significant hilar lymphadenopathy on CT (figure 2).
(A–C) CT thorax demonstrating pneumomediastinum.
CT thorax with red star highlighting normal appearance of R11 nodal staging area.
Lymph node cytology showed normal lymphoid tissue without evidence of malignancy.
Differential diagnosis
Given the lack of any symptoms or clinical history of vomiting or other risk factors for developing a pneumomediastinum, it is highly probable that this is an iatrogenic case of pneumomediastinum secondary to endobronchial ultrasound and transbronchial needle aspirate (EBUS-TBNA).
Treatment
The patient was recalled for review. Physical observations were normal and there was no significant abnormality on examination. There was no evidence of infection or dysphagia. No treatment was deemed necessary.
Outcome and follow-up
The patient was managed conservatively as she was stable. The CT showed no evidence of malignancy and at the time of the CT, the right middle lobe had reinflated. It was felt the middle lobe collapse could be secondary to infective changes including mucous plugging. The nodal aspiration showed no evidence of malignancy. The patient was discharged from the 2-week wait pathway and remained under the respiratory service.
Discussion
There are a limited number of case reports describing the presence of pneumomediastinum following EBUS-FNA.1–5 EBUS-TBNA is considered a safe procedure with a low complication rate.6 A study of 7345 patients undergoing EBUS-TBNA demonstrated a complication in only 1.23% of patients, with no cases of pneumomediastinum. Symptomatic presentation within 24 hours has been described, with relevant symptoms of neck swelling.1 2 Early development postprocedure has also been reported.5 7 In this case, the patient developed a cough immediately postprocedure, which could have precipitated the pneumomediastinum secondary to microperforation; however, this could have also exacerbated the air-leak potentially caused by a defect in the bronchial wall secondary to sampling.1 It is likely that the pneumomediastinum was caused secondary to needle trauma to the bronchial wall (known to be a rare cause of pneumomediastinum post-EBUS-TBNA).8 Pneumomediastinum has been described in patients with pre-existing lung disease9 and those with no apparent underlying conditions.10 All of the patients found to have a pneumomediastinum secondary to EBUS-TBNA underwent CT imaging to confirm the diagnosis as it is considered the most sensitive method of diagnosis.5 9 The management of all previously described cases has been conservative and consisted of observation, oxygen therapy and analgesia.4 5 9 This is explained by the fact that the mediastinal tissue is able to provide enough resistance against airflow (due to intrathoracic pressure) and so is able to be ‘self-healing’.8
When considering how to prevent a pneumomediastinum in this setting, it is worthwhile considering the extent of the procedure itself (needle gauge, size of target node, number of needle passes and operator experience) as relevant factors and carefully balancing the risks against the requirement for cancer diagnostic and staging information. It is important to stress that this is a rare complication of EBUS-TBNA.
This case also highlights the importance of contemporaneous cross-sectional imaging prior to invasive testing in order to best plan where to target or indeed to confirm that the test is necessary. The increased availability of CT scan slots in response to national directives such as the national optimal lung cancer pathway has largely rectified issues around investigation guidance and planning.
Learning points
Any invasive bronchoscopic or mediastinal procedure can lead to pneumomediastinum. Clinicians should be alert to this possibility and the relevant symptoms.
When suspecting pneumomediastinum, CT is the most sensitive method of diagnosis.
Pneumomediastinum, although a potentially serious diagnosis, can be managed with conservative measures in patients who are stable.
Contemporaneous cross-sectional imaging is essential for planning and guiding invasive tests for possible lung cancer.
Ethics statements
Footnotes
Contributors The Case Report was devised and researched by all authors. The report was originally written by AS and then approved and edited by KC and GM. The figures were collected by GM.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.