Hyperacute silicosis after bronchoscopy-induced melanoptysis in a lung transplant patient. A first report in literature

Abstract

Silicosis, a fibrotic lung disease caused by crystalline silica inhalation, presents unique challenges in lung transplantation. This case reports an unprecedented complication in a lung transplant recipient with chronic silicosis. A man in his 60s, post left single-lung transplantation for silica-induced pneumoconiosis, developed acute respiratory deterioration following routine bronchoscopy. Melanoptysis, followed by imaging showing extensive inflammatory involvement in the transplanted lung, required intubation and prone positioning. This case highlights the potential for residual silicotic material to trigger acute post-transplant complications. It underscores the importance of comprehensive pretransplant evaluation of occupational exposures and heightened awareness of silica-related complications in post-transplant care. The report emphasizes gaps in understanding long-term outcomes and optimal management strategies for lung transplant recipients with silicosis.

Silicosis is a progressive, irreversible fibrotic lung disease caused by the inhalation of respirable crystalline silica dust [1].

INTRODUCTION

Silicosis is a progressive, irreversible fibrotic lung disease caused by the inhalation of respirable crystalline silica dust [1]. When silica particles are inhaled, they trigger an inflammatory response, leading to fibrosis and impaired lung function. While the disease typically develops after 10–20 years of occupational exposure, it can occur more rapidly with intense exposure. In end-stage silicosis, lung transplantation may be the only available treatment.

Acute silicosis is a rare but severe form of the disease that can develop within weeks to months of massive silica dust exposure [1]. It is characterized by rapid onset of severe dyspnoea and respiratory failure. Radiologically, acute silicosis presents with a ground-glass appearance and consolidation on chest imaging, contrasting with the nodular pattern in chronic silicosis. Pathologically, the lungs show alveolar lipoproteinosis rather than silicotic nodules. The prognosis is generally poor, with high mortality rates.

Our report aims to detail the clinical course, diagnostic findings and management of a unique presentation of silicosis complications in a lung transplant recipient. We will review the patient’s clinical presentation, radiologic findings and disease course to highlight the key features of this rare form of acute silicosis.

CASE

A patient in his 60s, miner worker with complicated chronic silicosis and progressive massive fibrosis (PMF), requiring home oxygen therapy, underwent a left single-lung transplantation. Initially, his clinical evolution was favourable, and he was successfully extubated. However, due to persistent bronchial secretions and radiological evidence of pulmonary consolidation and atelectasis of the native lung, management with bronchoscopy for airway clearance was deemed necessary.

During the bronchoscopy procedure, bronchoalveolar lavage of both the native and transplanted lung was performed using 60 ml of saline solution per lung, and after the procedure, from the native lung, a persistent outflow of dark, sand-like content was observed and aspirated (Fig. 1). Following the procedure, the patient continued to expectorate material consistent with melanoptysis (the coughing up of black expectoration); the fluid was studied, and the result revealed silica crystals, and polymorphonuclear cells were observed in the liquid between the first and second Bronchoalveolar lavage (BAL). The biopsy of the extracted lung confirmed silicosis in chronic and active stages.

Figure 1:

Melanoptysis aspirate collected during bronchoscopy. The image shows a plastic container with dark, sand-like material aspirated from the native lung of the transplant recipient during the bronchoscopy procedure. This material is consistent with melanoptysis, a rare complication observed in patients with pneumoconiosis.

The patient experienced a rapid progression to respiratory deterioration, characterized by a drop in oxygenation and worsening of ventilatory mechanics. A same-day follow-up chest imaging study 1 h after the bronchoscopy revealed extensive acute inflammatory involvement in the transplanted lung (Fig. 2). Given this development, the medical team decided to intubate the patient and initiate prone positioning therapy for 48 h, the timeline is shown in Fig. 3. Additionally, steroid therapy was maintained. Subsequently, the patient’s condition improved favourably, ultimately allowing for successful extubation.

Figure 2:

Chest radiographs before and after bronchoscopy. Left: pre-bronchoscopy chest X-ray showing the patient’s post-transplant status with a left single-lung transplant. Right: post-bronchoscopy chest X-ray taken 1 h after the procedure, revealing extensive acute inflammatory involvement in the transplanted left lung, characterized by new diffuse opacities.

Figure 3:

Timeline of critical events in the post-transplant period. The figure illustrates the key clinical events and interventions from Days 1 through 8 post-transplantation.

DISCUSSION

This case presents a unique and significant complication of silicosis in a lung transplant recipient. The occurrence of melanoptysis and acute respiratory deterioration following bronchoscopy highlights the potential for residual silicotic material to complicate post-transplant care.

Current literature distinguishes between chronic and acute forms of silicosis. Chronic silicosis typically develops after 10–20 years of exposure, while acute silicosis can occur within weeks to months of intense exposure. Acute silicosis is characterized by rapid onset of severe symptoms, ground-glass opacities on imaging and alveolar lipoproteinosis pathologically. Chronic silicosis presents with a more gradual onset and nodular patterns on imaging. Both forms can lead to progressive respiratory failure, but acute silicosis generally has a poorer prognosis [1].

Melanoptysis, defined as the expectoration of black fluid or matter, is a rare complication in patients with pneumoconiosis, particularly those with PMF [2]. While typically associated with the cavitation of PMF masses due to ischaemia, infection or neoplasia, our case presents a unique scenario where melanoptysis occurred following a routine bronchoscopy in a lung transplant recipient. This highlights the potential for residual silicotic material in the native lung to complicate post-transplant care, even in the absence of active PMF. Although our patient did not experience massive melanoptysis, the volume of expectorated material appears to be a relevant factor in the development of subsequent complications.

The sudden onset of respiratory failure requiring intubation and prone positioning in our patient represents an atypical and severe manifestation following melanoptysis, raising the possibility of a hyper-acute silicotic reaction triggered by the mobilization of silica particles during the procedure. Previous literature has suggested that the volume of melanoptysis can be an important indicator of potential respiratory compromise [3]. In our case, while the volume was not massive, the rapid development of respiratory failure emphasizes the need for close monitoring of these patients, particularly in the context of lung transplantation.

Bronchoscopy is an essential diagnostic and therapeutic tool in post-lung transplant management, used to evaluate anastomoses, detect infections and treat airway complication [4]. However, in patients with silicosis, this procedure carries additional risks, such as the melanoptysis observed in this case [2, 5]. This underscores the importance of careful procedural planning and vigilant monitoring for potential silica-related complications in transplant recipients with a history of occupational exposure, even years after cessation of exposure.

Despite our understanding of silicosis pathophysiology, significant knowledge gaps remain. There is limited information on the long-term outcomes of lung transplantation in patients with silicosis, particularly regarding complications from residual silicotic material. The mechanisms by which silica particles might trigger acute inflammatory responses in transplanted lungs are not well understood. Additionally, optimal management strategies for such complications in transplant recipients are not established.

This case report has several limitations. As a single case, it cannot establish causal relationships or generalize findings to all silicosis patients undergoing lung transplantation. The lack of long-term follow-up data limit our understanding of the patient’s ultimate outcome. Additionally, without detailed occupational history and exposure measurements, we cannot fully characterize the patient’s silica exposure or definitively attribute the complications to silicosis.

CONCLUSION

In conclusion, this case highlights the potential for unexpected complications in lung transplant recipients with a history of silica exposure. It emphasizes the need for comprehensive pretransplant evaluation of occupational exposures, heightened awareness of potential silica-related complications post-transplant and careful procedural planning in these patients, particularly for interventions like bronchoscopy. Further research into the long-term outcomes and optimal management of transplant recipients with silicosis is warranted. The case underscores the ongoing relevance of silicosis as a public health concern, even in the context of advanced treatments like lung transplantation. It calls for continued efforts in silica exposure prevention and improved surveillance, particularly in high-risk industries and regions.

FUNDING

This study did not receive any financial resources or support.

Conflict of interest: none declared.

DATA AVAILABILITY

The data underlying this article will be shared on reasonable request to the corresponding author.

PATIENT CONSENT STATEMENT

The patient has given written informed consent for the use of his images, clinical registry chart and the publication of this case report.

DECLARATION OF GENERATIVE AI AND AI-ASSISTED TECHNOLOGIES IN THE WRITING PROCESS

During the preparation of this work, the authors used Claude.AI to improve the readability of this paper, using it like a language editing service. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.

AUTHOR’S AGREEMENT STATEMENT

All authors have approved the final article, agreed to be accountable for all aspects of the work and acknowledge that all those entitled to authorship are listed as authors.