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 Table of Contents  
Year : 2020  |  Volume : 18  |  Issue : 2  |  Page : 203-208

Yield of medical thoracoscopy in undiagnosed exudative pleural effusion: a 3-year retrospective multicenter study

1 Chest Diseases, Faculty of Medicine for Girls, Al-Azhar University, Cairo, Egypt
2 Chest Diseases, Faculty of Medicine, Al-Azhar University, Cairo, Egypt

Date of Submission16-Feb-2020
Date of Decision28-Feb-2020
Date of Acceptance14-May-2020
Date of Web Publication24-Jul-2020

Correspondence Address:
MD Eman Sobh
Department of Chest Diseases, Faculty of Medicine for Girls, Al-Azhar University, Al-Zahraa University Hospital, Abbassia, Cairo 11517
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/AZMJ.AZMJ_28_20

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Background The diagnosis of the etiology of exudative pleural effusion is a great challenge in clinical practice.
Aims To evaluate the diagnostic value of medical thoracoscope in unexplained exudative effusions and the frequency of various diagnoses in a multicenter study in Egypt.
Patients and methods A retrospective analysis was done of all thoracoscopies done at our centers for diagnosis of the cause of the exudative pleural effusion.
Results Among 542 thoracoscopies performed at our centers, definite diagnosis was reached in 476 (87.8%) cases. Malignancy was the most common diagnosis (60.7%) followed by tuberculosis (24.5%).
Conclusion Thoracoscopy was a safe and efficient tool for diagnosis. Malignancy and tuberculosis were the most common etiologies.

Keywords: exudative pleural effusion, pleural biopsy, pleural effusion, thoracoscopy, undiagnosed pleural effusion

How to cite this article:
Sobh E, Elsawy SB, Ahmed ME. Yield of medical thoracoscopy in undiagnosed exudative pleural effusion: a 3-year retrospective multicenter study. Al-Azhar Assiut Med J 2020;18:203-8

How to cite this URL:
Sobh E, Elsawy SB, Ahmed ME. Yield of medical thoracoscopy in undiagnosed exudative pleural effusion: a 3-year retrospective multicenter study. Al-Azhar Assiut Med J [serial online] 2020 [cited 2020 Oct 25];18:203-8. Available from: http://www.azmj.eg.net/text.asp?2020/18/2/203/290604

  Introduction Top

The identification of the cause of exudative pleural effusion carries a great challenge in the respiratory clinical practice [1]. The evaluation of pleural effusion includes chemical analysis, cytologic examination, and microbiologic studies [2]. Cytologic examination of the pleural effusion is of low diagnostic yield, and immunohistochemical studies are difficult to be performed on pleural fluid cells [3], and obtaining a pleural biopsy is the key tool for diagnosis [4]. Various diagnostic tools had been studied including blind pleural biopsy, image-guided biopsy, thoracoscopy, and open pleural biopsy [5],[6]. The yield for closed pleural biopsy may be low owing to different factors, including early stage of the tumor, unreachable area by needle, and inexperienced physician [7]. Thoracoscopy was first introduced in medical practice by Hans Christian Jacobaeus in 1990 who used rigid thoracoscope for the evaluation of tuberculous empyema [8]. Then video-assisted surgical thoracoscopy was performed under general anesthesia [9]. A less-invasive and less-expensive single-port medical thoracoscopy has been used by pulmonologists under local anesthesia and conscious sedation for diagnostic and therapeutic purposes in the past few years [3]. Various studies reported diagnostic value of medical thoracoscope in the diagnosis of unexplained exudative effusions; however, the results are greatly variable [9]. Thoracoscopy is the option of choice for obtaining pleural biopsy when the diagnosis of exudative effusion remains unclear, and it is the most sensitive diagnostic tool in patients with cytology-negative pleural effusion and suspected malignancy [5]. The aim of this study was to evaluate the diagnostic value of medical thoracoscope in unexplained exudative effusions and the frequency of various diagnoses in a multicenter study in Egypt.

  Patients and methods Top

This was a retrospective-descriptive study of all patients who underwent medical thoracoscopy at our university hospitals, Cairo. These are large tertiary referral hospitals that receive patients from different geographic areas across Egypt. The study included the data of patients attending these hospitals from 2017 to 2019. All cases had exudative pleural effusion according to Light’s criteria [10]. All initial tests performed were undiagnostic including cytologic examination of the fluid and initial test for tuberculosis.

Ethical consideration

The study protocol was approved by the institutional review board and research ethics committee of our institute (approval number 20190821127), and the consent was waived owing to the retrospective nature of the study. All data were kept confidential, and the data recorded were anonymized.

Medical thoracoscopy procedure

Thoracic ultrasound was performed before thoracoscopy to assess for the nature, amount, and septation of pleural effusion and to assess the suitability of thoracoscopy; during thoracoscopic procedure to choose entry point and to guide thoracoscope; and after the end of the procedure to assess for complications [11],[12],[13]. Medical thoracoscopies were performed in the pulmonary endoscopy suite using a seven-mm rigid thoracoscope set (Karl Storz Endoscope; Karl Storz; Tuttlingen, Germany) and one 3.0-mm biopsy forceps. The procedure was performed by pulmonologists under local anesthesia using lidocaine local injection and conscious sedation using midazolam while the patient is lying on lateral decubitus with the pleural effusion side up [14] and his/her arms positioned over his/her head to widen intercostal space [14]. An anterolateral thoracic approach in the fifth or sixth intercostal space is used; local anesthesia was applied at the site of entry. A single-port technique was used to minimize pain. One-centimeter incision was done, followed by blunt dissection to introduce the trocar followed by insertion of the thoracoscope [15]. Once the lung was collapsed; suction of pleural fluid was done to clarify the field. The thoracoscopist inspected the whole pleural cavity in slow circular motion for gross appearance and then took two to four biopsies by ‘lift and peel’ technique from the apparently affected areas or from different areas if no apparent pathologic abnormalities were seen [16]. All samples were evaluated for culture and sensitivity for bacteria, fungi, and mycobacteria, for cytopathology of pleural fluid and histopathologic evaluation of pleural tissue. A chest tube connected to an underwater sealed drain was inserted [17]. Ultrasound was performed after thoracoscopy for the assessment of complications [13]. The chest tube was removed when the lung is fully expanded with no evidence of air leak [16] and the drainage is less than 50 ml/day for two consecutive days [18].

Ethical issues

We obtained approval to perform this study from the institutional review board and ethics committee of our institute (AFMG-IRB), with approval number 20190821127, and informed consent was waived as the data were collected anonymously.

Data management

We collected data from medical records, which included demographic data, pleural fluid analysis, and results of medical thoracoscopy gross and microscopic pathology and final diagnosis. The outcome was also recorded.

Statistical analysis

All data were anonymized and were analyzed using Statistical Package for Social Science, version 15 (IBM Corp., Armonk, New York, USA). Categorical values were expressed as frequency (percentage), whereas continuous data were presented as mean±SD or median (interquartile range). A two-sided P value less than 0.05 was considered statistically significant.

  Results Top

During the study period, 542 consecutive thoracoscopies were performed at our centers. Demographic data of the studied population are presented in [Table 1]. They were 316 (58.3%) males and 226 (41.7%) females. Smokers constituted 104 (19.2%) cases. A total of 196 (36.16%) patients lived in areas with risk of asbestos exposure (Helwan, Shubra El Kheima), and half of them had moderate to high risk of occupational exposure to asbestos. Dyspnea was the most common symptom in 529 (97.6%) followed by chest pain in 293 (54.1%), and right-side pleural effusion in 274 (50.6%). Cytopathology revealed 289 (53.3%) cases were positive for malignancy, whereas 90 (16.6%) cases had a positive direct smear result for acid-fast bacilli ([Table 2]).
Table 1 Demographic data and basic characteristics of the studied population

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Table 2 Clinical data and imaging of the studied cases

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A total of 542 diagnostic medical thoracoscopies were done during the study period. The visual assessment suspected diagnosis and primary histopathology are shown in [Table 3]. Thoracoscopy resulted in a definite diagnosis in 476 (87.8%) cases, whereas 66 (12.2%) were still undiagnosed. Malignancy was the most prevalent diagnosis of the studied cases [329 (60.7%)] followed by tuberculosis [133 (24.5%)]. Malignant mesothelioma was the most common type of malignancy [242 (445%)] followed by metastatic adenocarcinoma [75 (13.8%)]. Other types included lymphoma [six (1.1%)], thymoma [one (0.2%)], small-cell lung cancer [three (0.6%)], and squamous cell carcinoma [two (04%)]. Nonspecific inflammation represents 14.8% (80 cases), with bacterial empyema proved in 14 (2.6%) cases ([Figure 1],[Figure 2],[Figure 3]). Regarding complications, no procedure-related mortality occurred at our centers; minor complications included prolonged air leak and subcutaneous emphysema, which resolved completely.
Table 3 Thoracoscopic examination

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Figure 1 Final diagnosis of the studied cases. SCLC, small-cell lung cancer; SCC, squamous cell carcinoma; TB, tuberculosis.

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Figure 2 Thoracoscopic pleural biopsy of chronic inflammation and fibrosis of pleura showing diffuse infiltration with chronic inflammatory cells with fibrosis (H&E, ×200).

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Figure 3 Thoracoscopic pleural biopsy of biphasic (mixed) mesothelioma; histopathology revealed fibrohyaline papillae lined by neoplastic mesothelial cells (uniformly cuboidal cells with large vesicular nuclei and prominent nucleoli) and fascicular proliferation of spindle cells with oval nuclei, scanty cytoplasm, and occasionally prominent nucleoli (H&E, ×300).

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  Discussion Top

Although there is presence of extensive investigations including chemical and cytopathologic examinations, a large percentage of pleural effusion cases remain undiagnosed and considered a great challenge in clinical practice [1],[2]. Obtaining tissue biopsy in cases of unexplained exudative pleural effusion after initial thoracentesis is recommended [5],[19]. Medical thoracoscopy is the first step after inconclusive thoracentesis if malignancy is suspected [19]. A high proportion of cases with undiagnosed pleural effusion suspicious of malignancy require a pleural biopsy (tissue is the issue) [6]. The aim of this study was to investigate the diagnostic yield of medical thoracoscope in unexplained exudative effusions and the frequency of various diagnoses in a multicenter study in Egypt. We found 542 thoracoscopies performed for the diagnosis of unexplained pleural effusion after initial cytochemical assessment including negative results for tuberculosis and nonconclusive cytopathologic examination.

In this study, the median age was 57 years. Dyspnea was the most common symptom followed by pleuritic chest pain ([Table 2]). Dyspnea, cough, and pleuritic chest pain are common symptoms in pleural effusion in previous studies [20]. The presence of pleuritic chest pain in cases of pleural effusion indicates a local pleural process [5].

In the current study, the indication of thoracoscopy was to obtain a pleural biopsy for diagnosis. Thoracoscopy is preferred to blind pleural biopsy as it allows visualization of pleural space and for taking a pleural biopsy from suspicious areas. In addition, it enables obtaining multiple large biopsies for molecular studies [7]. In this study, ultrasound was used before thoracoscopy; ultrasound was useful in the identification of the nature of pleural fluid ([Table 2]) and to guide thoracoscopy, especially in presence of loculations. The Official American Thoracic Society, Society of Thoracic Surgeons, and Society of Thoracic Radiology (ATS/STS/STR) clinical practice guideline recommended the use of thoracic ultrasound to guide pleural intervention and management in case of suspected malignancy [11].

In this study, thoracoscopic yield allowed a definite diagnosis in 476 (87.8%) of cases. Previous studies revealed similar results, where an excellent yield (95.8%) was reported in the study by Dhanya and Ravindran [21]. Moreover, in the study by Hansen et al. [22], thoracoscopy provided diagnosis in 90.4% of the cases. Similarly, Patil et al. [23] and Hucker et al. [24] obtained near similar results (85.3 and 80.3% respectively). However, Mootha et al. [25] reported a yield of 74.3%. The yield differs according to diagnosis. Rahman and Gleeson [26] reported 92.6% sensitivity (1268/1369) and Diacon et al. [27] obtained sensitivity of 100% for thoracoscopy to diagnose tuberculosis.

Direct visualization can discriminate between normal and abnormal areas, allowing for targeted biopsy of nodular, thickened, or erythematous areas. In the absence of visual abnormality, thoracoscopy allows for biopsies to be taken safely from the parietal pleura [25]. In the current study, thoracoscopy allowed direct vision, and the most common abnormal examination was multiple pleural nodules in 265 (48.9%) cases ([Table 3]), and this visualization allowed taking biopsies from abnormal sites for proper diagnosis. The same results were obtained in the study by Dhooria et al. [28], who reported that adhesions and nodules were present in 65.9% of cases. Patil et al. [23] reported that black anthracotic patches were the most common gross appearance, followed by thickened nonsmooth pleura and pleural nodules. The pathologic involvement of the pleura is different in various geographic regions [28].

In this study, pleural fluid cytology detects malignancy in 289 (53.3%). Cytology can obtain malignant cells in ∼60% of cases; however, tissue diagnosis is often required to confirm the diagnosis and perform further molecular testing if required and to guide management [6].

Pleural malignancy was the most common diagnosis obtained in this study in 329 (60.7%) cases followed by tuberculosis in 133 (24.5%) cases ([Table 3]), whereas 66 (12.2%) cases remained undiagnosed, and tissue analysis showed chronic nonspecific inflammation. Dhooria et al. [29] reported similar results (malignancy 31.7% and tuberculosis 25.6%) and 39% of cases remained undiagnosed (nonspecific pleuritis). Patil et al. [23] found malignancy in 56.6% of cases, and tuberculosis was the most common nonmalignant diagnosis followed by parapneumonic effusion. Chronic nonspecific inflammation was relatively low in our study at 18.8% than previous studies at 20.6% in the study by Hucker et al. [24], 31% in Hansen et al. [22], and 38.2% in Blanc et al. [1].

Mesothelioma constitutes 44.5% of cases in this study. Looking at the demographic nature of the current cases, we found that 36.16% were living in areas with risk of asbestos exposure and 50% had occupational exposure to asbestos at any point during their life. The relationship between asbestos exposure and mesothelioma is well established [30].

Although it has an invasive nature, medical thoracoscopy has low rate of complications [6]. In our study, no mortality was seen, and only a few cases had minor complications. Rahman and Gleeson [26] in a systematic review of 47 studies found a mortality rate of 0.34%, and major complications included hemorrhage, empyema, bronchopleural fistula, air-leak or pneumothorax, pneumonia, and tumor seeding at port site in 1.8%. Dhooria et al. [29] have a relatively higher rate of complications in 82 of 154 thoracoscopies and included empyema, re-expansion pulmonary edema, persistent air-leak, minor bleeding, and subcutaneous emphysema; however, no procedure-related deaths were reported.

  Conclusion Top

In conclusion, thoracoscopy is a safe and excellent diagnostic tool for the diagnosis of unexplained pleural effusion. It carries minimal risk and therapeutic opportunity. Malignancy and tuberculosis were the most common pathologic.

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Conflicts of interest

There are no conflicts of interest.

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  [Table 1], [Table 2], [Table 3]


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