Medical Thoracoscopy in Diagnosis and Management of Silicotuberculosis with Pneumothorax: A Report of a Rare Case

Introduction

Silicosis is an interstitial lung disease that is progressive and irreversible. It is one of the types of pneumoconiosis that is caused by crystalline silica inhalation. This disease affects millions of workers in various countries involved in dust-filled activities [1,2]. Based on a World Health Organization (WHO) report, pneumoconiosis causes 30 000 deaths and 12 880 000 disabilities each year. Asia accounts for up to two-thirds of deaths from occupational diseases globally, followed by Africa and Europe [3].

The relationship between silicosis and tuberculosis (TB) has long been known. The probability that a person with silicosis has active TB is 2–30 times higher than in those who do not have silicosis. Silicotuberculosis is a condition in which a person has silicosis and a TB infection simultaneously [2]. TB is one of the causes of bronchopleural fistula (BPF). This fistula can form due to the fibrosis process that occurs in Mycobacterium tuberculosis (MTB) infections or the rupture of the cavity formed in active MTB infections. Since silicosis itself can cause spontaneous pneumothorax complications, the possibility of BPF in silicotuberculosis patients can be predicted to increase, even if the incidence rate is not known with certainty [2].

A finding of silica is mandatory to establish the diagnosis. Broncho-alveolar lavage (BAL) is an important and standard examination to detect silica. In certain cases, the detection of silica can be obtained by mineral analysis of lung biopsy [2,4]. No reports have been found regarding the use of thoracoscopy to establish a diagnosis of silicotuberculosis. However, in cases with a clearly defined target lesion, lung biopsy via thoracoscopy can be an option for diagnosing silicosis through histopathological examination, which may reveal silicotic nodules or features of progressive massive fibrosis, as well as mineral analysis [2]. Therefore, this report presents a case highlighting the role of thoracoscopy in the diagnosis of silicotuberculosis.

Case Report

A 45-year-old Indonesian man came to the emergency room (ER) of Dr. Soetomo General Hospital, Indonesia, with shortness of breath beginning 10 hours before. Shortness of breath and pain in the left side of the chest was suddenly felt after the patient defecated. He also had a cough lasting 3 weeks, which had worsened with yellowish sputum 5 days before admission. He also had a fever accompanied by nausea for 5 days. His appetite had decreased in the last 4 months, and he had lost around 30 kg body weight in the last 6 months. Sixteen days before, the patient’s sputum was put through a GeneXpert MTB/Rif test because of his concerns. The result was that rifampicin-sensitive Mycobacterium tuberculosis was detected. He then took a standard anti-tuberculosis drug (ATD) for 2 weeks before finally being admitted to the ER due to shortness of breath.

Previously, the patient had worked in a stone quarry for 7 years. He admitted that he had never used any personal protective equipment (PPE). He also had a habit of smoking up to 48 cigarettes per day for more than 20 years and stopped when he became ill. None of the patient’s other family members had the same disease.

The patient was underweight. His general condition at the ER was weak. An assessment of the consciousness using the Glasgow Coma Scale (GCS) was E3V5M6. His blood pressure measured 100/70 mmHg, with a heart rate of 110 beats per minute, a respiratory rate of 30 breaths per minute, a body temperature of 36.7°C, and an oxygen saturation of 95% with a non-rebreathing mask (NRM) at 15 L/m. A physical examination of the chest revealed asymmetrical chest movements with the trachea deviated to the right, hyper-resonance on the left hemithorax, decreased vesicular auscultation in the left hemithorax, and bronchovesicular in the right hemithorax accompanied by crackles in the upper two-thirds of the right hemithorax, without wheezing.

Laboratory results showed leukocytosis, neutrophilia, lymphopenia, increased serum transaminase, hypoalbuminemia, hyperbilirubinemia, increased procalcitonin, and decreased sodium and chloride. A chest X-ray showed a left pneumothorax. In addition, fibro-infiltrates were found in all right lung parenchyma, which supports a diagnosis of pulmonary tuberculosis accompanied by non-specific infection.

The patient’s shortness of breath decreased after inserting a chest tube in the left hemithorax. The ATD was changed to a non-hepatotoxic regiment (750 mg streptomycin, 750 mg levofloxacin, and 750 mg ethambutol once a day) because there was an increase in the liver function test. Levofloxacin was also administered to treat non-specific lung infections.

On the third day of treatment, the patient experienced shortness of breath again. The chest X-ray evaluation revealed a pneumothorax in the right hemithorax. The chest tube was inserted into the right hemithorax. A high-resolution computed tomography (HRCT) examination of the thorax was performed, showing the right and left pneumothorax had a chest tube attached, accompanied by pulmonary TB with a bronchopleural fistula. Bilateral opacities observed on HRCT with a diameter exceeding 1 cm are consistent with progressive massive fibrosis in pneumoconiosis (Figure 1). The patient then underwent medical thoracoscopy of the left hemithorax, which is still exclusively available in Indonesia. Multiple bronchopleural fistulae were found in the medical thoracoscopy (Figure 2). The lung biopsy procedure from thoracoscopy was carried out for histopathological examination and silica analysis. The histopathology (hematoxylin-eosin staining) showed a dense patch of inflammatory lymphocytes, histiocytes, and plasma cells. Among these were foci of epithelioid-shaped histiocyte cells, faintly forming granulomas, with diagnosis of a chronic inflammatory process suspected to be linked to tuberculosis (Figure 3). Spectrophotometry found silica at a level of 920.19 ppm SiO2.

After a few days of treatment, a follow-up chest X-rays showed full lung expansion. The right chest tube was successfully removed. However, an expiratory bubble was found in the water seal drainage system of the left hemithorax. As a result, the left chest tube could not be removed. Based on discussions among a multidisciplinary team of pulmonologists, radiologists, and thoracic surgeons, it was decided that the patient could not undergo surgery due to the presence of multiple bronchopleural fistulas, the poor prognosis of the underlying disease, and the unknown outcomes following surgery. He was scheduled for discharge with a left chest tube connected to a dry seal drain (one-way valve), indicating a stable yet guarded outcome. His breathing improved and consciousness returned to normal. The ATDs administered after the patient’s liver function improved were 450 mg rifampicin, 200 mg isoniazid, 1.000 mg pyrazinamide, and 750 mg ethambutol once a day. The patient survived for 1 month at home before dying, highlighting resilience and the need for lung transplantation access in Indonesia.

Discussion

Silicosis is pneumoconiosis caused by inhalation and deposition of free silica particles in the lungs [5]. Construction work, surface and underground mining, tunneling, and foundry work are the main sources of exposure to silica dust [2]. In this case, the patient had a history of working in a stone quarry for 7 years and had never used PPE, which could have caused silicosis.

Silica particles that enter the lungs interfere with the immune system’s effort to eliminate tuberculosis [6]. As previously mentioned, a person with silicosis has a risk of being infected with active tuberculosis at a rate of 2 to 30 times higher than someone without silicosis. Even exposure to silica without silicosis can predisposed to TB infection [2,7].

Anamnesis regarding a history of working with exposure to silica dust is important to establish a silicosis diagnosis. TB should be considered if there are systemic symptoms such as fever and weight loss. The bacteriological examination is essential for establishing a TB diagnosis and determining the optimal ATD regimen [2,8].

If there is suspicion of silicosis, a radiographic examination can support the diagnosis. The opacity obtained from imaging is usually round with a diameter of 3–10 mm. However, smaller and more irregular sizes can also be found. The lesions are typically distributed in the upper region. Enlargement of lymph nodes in the hilar region (eggshell calcifications) is often seen before the formation of lesions in the lung parenchyma. Furthermore, HRCT can be performed, especially when chest X-rays are inconclusive. In this case, HRCT was conducted primarily to look for BPF as the cause of the pneumothorax. The presence of progressive massive fibrosis is also observed on HRCT, which supports the diagnosis of silicosis [2,8].

Silica detection in BAL is an important examination. A lung biopsy can also differentiate this disease from malignancy, tuberculosis, or other diseases. Biopsy samples can be examined under a microscope with polarized lighting or by mineral analysis [2,4]. Our patient’s silicosis diagnosis was established based on an analysis of lung biopsy samples from a medical thoracoscopic procedure. Silica with a content of 920.19 ppm SiO2 was found through the spectrophotometric method. To the best of our knowledge, the literature contains no reports on the use of medical thoracoscopy for obtaining lung biopsy samples for the diagnosis of silicosis. Analysis of lung biopsy samples, especially from medical thoracoscopy, is rarely performed because this procedure is more invasive than BAL. No studies have assessed whether BAL or biopsy of the lung is more sensitive in detecting silica particles. However, this case report demonstrates that a high level of silica can be detected by analyzing samples from lung biopsies. This procedure may also be considered in patients with pneumothorax who are indicated for chest tube placement. In cases of non-multiple bronchopleural fistulas, thoracoscopy may also serve as a therapeutic procedure for repairing the fistulas.

Pleural abnormalities are very rare in silicosis. The only known complication of silicosis to the pleura is secondary spontaneous pneumothorax [9]. This pneumothorax is generally unilateral. Bilateral pneumothorax has been reported in several articles [10,11], but this complication is very rare. The pneumothorax is caused by inflammation that occurs due to exposure to silica in the lungs, causing elastic fiber tissue to form in the alveolar walls. Massive fibrosis of the lung tissue makes it more difficult for it to stretch, thereby increasing elastic recoil. Several investigations have reported that bullae formation and emphysema are causes of pneumothorax. If this bulla ruptures, a pneumothorax can occur [8,9].

There is no effective drug to treat silicosis. Therefore, the most important course of action to manage silicosis is prevention. Preventive efforts need to be carried out in workplaces with silica dust exposure. Dust levels must be controlled to prevent them from exceeding the recommended threshold. To circulate clean air and reduce dust accumulation, good ventilation is needed. The use of PPE such as masks must always be considered. Water utilization can be useful in reducing dust in some workplaces [8,12].

Once the silicosis diagnosis is established, treatment focuses on preventing the disease from progressing and managing complications. Although the disease may progress even after exposure has been removed, patients should still be advised to avoid exposure and reduce the rate of disease progression. There is interest in using whole-lung lavage to remove silica from the lungs, but it is unclear what the benefits of this action are in preventing disease progression [2].

One of the silicotuberculosis complications that occurred in our patient was bilateral pneumothorax due to the presence of BPF. Some patients can recover from BPF on their own [11], but others require surgery or another advanced management [10,13,14]. In our patient, surgery was considered for managing BPF in the left hemithorax because the fistula could not close spontaneously. However, conservative management was chosen because the patient’s clinical condition was inoperable, and the large number of BPFs made him prone to recurrent pneumothorax after surgery. Patients with severe diseases, as in this case, may be suitable candidates for lung transplantation [2]. Unfortunately, lung transplantation is not yet available in developing countries such as Indonesia.

Medical thoracoscopy proved to be an effective diagnostic tool in confirming silicotuberculosis with bilateral pneumothorax in this rare case, providing crucial insights into the underlying pathology and guiding appropriate management strategies despite the complexity and severity of the condition. However, it is limited by the reliance on an invasive lung biopsy, which may not be the most practical diagnostic method compared to less invasive alternatives.

Conclusions

This case report highlights the important role of thoracoscopy as a procedural option for obtaining lung biopsy samples in patients with silicotuberculosis. As an invasive procedure, thoracoscopy should be considered in specific cases, such as the one presented in this report. Further research into less invasive diagnostic methods and more effective treatments for silicotuberculosis are needed. The management of silicotuberculosis requires advanced medical equipment and significant costs. Preventive efforts from various stakeholders are essential to reduce the incidence of silicotuberculosis.