Bilateral Pneumothorax after a Transbronchial Lung Cryobiopsy for Interstitial Lung Disease (2024)

Abstract

We herein report a case of bilateral pneumothorax after a unilateral transbronchial lung cryobiopsy (TBLC). A 73-year-old man with no history of cardiothoracic surgery underwent a TBLC for the reevaluation of interstitial lung disease. Five hours later, he developed bilateral pneumothorax, pneumomediastinum, and subcutaneous emphysema. He underwent bilateral chest drainage and was discharged 18 days later. The lung biopsy specimens obtained from the TBLC contained visceral pleura and bronchial cartilage, suggesting bronchial injury as the cause of the bilateral pneumothorax.

Keywords: bilateral pneumothorax, bronchial injury, buffalo chest, interstitial lung disease, Macklin effect, transbronchial lung cryobiopsy

Introduction

In recent years, a transbronchial lung cryobiopsy (TBLC) has been proposed as an alternative to a surgical lung biopsy (SLB) in the diagnosis of interstitial lung disease (1). The most common complications of a TBLC are pneumothorax and bleeding. The incidence of pneumothorax as a complication of a TBLC was reported to be 9% (2). However, to our knowledge, there is only one reported case of bilateral pneumothorax after a TBLC (3).

We herein report a valuable case of bilateral pneumothorax after a TBLC.

Case Report

A 73-year-old man who had undergone a transbronchial lung biopsy (TBLB) and SLB from the right lung was diagnosed with nonspecific interstitial pneumonia 2 years before his initial visit. He was treated with prednisolone and nintedanib for approximately one year. Chest computed tomography (CT) showed peribronchovascular reticulation and no bulla/bleb, cysts, or emphysema in the lung fields (Fig. 1). The oxygen saturation was 98% while he was breathing ambient air. We performed a TBLC from the right lower lobe (B⁸_b, B⁹_b, B¹⁰_a) to reevaluate interstitial lung disease.

There was no supplemental oxygen or obstruction of the intubation tube during TBLC. Fluoroscopic imaging at the end of a TBLC showed no pneumothorax or pneumomediastinum. His oxygen saturation was more than 95% without supplemental oxygen. Five hours later, however, he developed advanced subcutaneous emphysema extending from his face to his abdomen. The oxygen saturation was 89% while he was breathing ambient air. Chest radiography and chest CT showed bilateral moderate pneumothorax, pneumomediastinum, and subcutaneous emphysema (Fig. 2A). Chest CT images also showed air around bronchovascular bundles (Fig. 2B). He was immediately given bilateral chest drainage with chest tubes. There were air leaks from both lungs, and both lungs expanded. The biopsy specimens obtained from the TBLC contained visceral pleura and bronchial cartilage (Fig. 3).

After 14 days, the air leaks from both lungs had disappeared, and the chest tubes were removed from the left and right sides in that order. His pneumothorax did not worsen, and he was discharged on day 18. At a later multidisciplinary discussion, periodic acid Schiff-positive material was found in the alveolar space of the biopsy specimen, and alveolar proteinosis was suspected.

Discussion

A TBLC for interstitial lung disease is usually performed unilaterally. Therefore, pneumothorax as a complication is generally unilateral, while bilateral pneumothorax is rare. There have been several case reports of bilateral pneumothorax by a unilateral lung biopsy. Most of them concluded that buffalo chest was the cause (4-8). Only one case was reported to be caused by bronchial injury (3). In the present case, buffalo chest was initially suspected as the cause, but it turned out to be due to bronchial injury.

Buffalo chest refers to the presence of communication between the left and right thoracic cavities. The human thoracic cavity is normally divided into left and right sides by the mediastinal pleura, but congenital defects or iatrogenic injury to the mediastinal pleura can cause communication. Most case reports of buffalo chest are communications of the pleural cavities due to iatrogenic injury of the mediastinal pleura, and most of them are related to cardiothoracic surgery (9). In the present case, buffalo chest was ruled out because there was no thinning of the mediastinum on chest CT and no history of cardiothoracic surgery. The biopsy specimens obtained from the TBLC contained bronchial cartilage, suggesting that there was bronchial injury.

Bronchial injury is a traumatic or iatrogenic injury to the bronchi. Most reports of iatrogenic injury are central bronchial injuries, such as injuries during tracheal intubation (10,11). Iatrogenic bronchial injuries may improve with conservative treatment (12). The present case also improved with only chest drainage for approximately two weeks.

We hypothesized that the mechanism underlying contralateral pneumothorax in unilateral bronchial injury was air movement through the mediastinum. The air around the bronchovascular bundles on chest CT after the TBLC suggested that air escaping from the injured bronchus had moved into the mediastinum and reached the left pulmonary hilum while detaching from the bronchovascular sheath. This air movement is referred to as the Macklin effect (13,14). We suspect that severe pneumomediastinum occurred as a result of air escaping from the injured bronchus and accumulating in the mediastinum. We further hypothesized that a partial disruption of the left mediastinal pleura resulted in air inflow from the mediastinum into the left thoracic cavity. We also speculate that the use of corticosteroids and nintedanib may have weakened the tissues and increased the risk of bronchial and pleural injuries.

The procedural problem that caused bilateral pneumothoraces was probably due to the central side of the biopsy position. In a TBLC for interstitial lung disease, a lung biopsy at a distance of 1 cm from the pleura is recommended (15,16). In this case, the biopsy was performed with fluoroscopic imaging. However, the lung tissue from B¹⁰ had been biopsied from the central side. We should note that when performing a dorsal lung biopsy, it is difficult to obtain a tangential fluoroscopic image, and even 1 cm on the fluoroscopic image may actually be longer than 1 cm.

We suggest two ways to prevent severe pneumothorax after a TBLC as in this case. The first is to avoid performing a dorsal lung biopsy whenever possible, and the second is to perform chest radiography a few hours after the TBLC for early detection of pneumothorax.

The authors state that they have no Conflict of Interest (COI).

References