CT Manifestations of Late Sequelae in Patients with Tuberculous Pleuritis

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1 CT Manifestations of Late Sequelae in Patients with Tuberculous Pleuritis T uberculous pleuritis remains one of the major causes of pleural effusion with an incidence ranging from as high as 86% in a population with a high number of HIV-positive patients to 25% in a population with high incidence of pulmonary tuberculosis [1]. Tuberculous pleuritis occurs when a subpleural focus of Mycobacterium tuberculosis ruptures into the pleural space initiating a delayed hypersensitivity reaction, by hematogeneous dissemination of mycobacteria, or by direct extension of the primary disease [2]. Tuberculous pleuritis usually resolves completely even in the absence of treatment [1]. However, in some patients, chronic complications occur during the healing of tuberculous lesions or as late sequelae. The complications of tuberculous pleuritis are as varied as its pulmonary manifestations. CT scans can be valuable in the diagnosis of the chronic complications or the late sequelae of tuberculous pleuritis, which manifest as pleural thickening, calcifications, fibrothorax, chronic persistent effusion, including pseudochylothorax, empyema necessitatis, bronchopleural fistula, and malignancy. Received pril 19, 2000; accepted after revision July 24, Jung-h Choi 1, Ki Taek Hong 1, Yu-Whan Oh 1, Myung Hee Chung 2, Hae Young Seol 1, Eun-Young Kang 1 Pleural Thickening and Fibrothorax Tuberculous pleuritis often leaves sequelae ranging from minimal pleural thickening, seen as obliteration of the costophrenic sulcus, to severe thickening, seen as fibrous tissue and calcification encompassing and restricting the lung and referred to as fibrothorax. Fibrothorax may be associated with extensive volume loss of the ipsilateral lung and even with ventilatory impairment [3]. On CT, pleural thickening is depicted as a layer of soft-tissue density at the chest wall lung interface (Figs. 1 and 2). CT can easily show pleural calcification, which is a frequent associated finding of pleural thickening caused by tuberculosis. Fibrous obliteration of the pleural space, or fibrothorax, may develop as a result of organized hemorrhagic effusions, tuberculous effusions, other empyemas, and benign asbestos-related pleurisy [3]. Several radiologic features allow differentiation among these various causes of fibrothorax. On radiography and CT, evidence of underlying parenchymal disease, extensive calcification of the fibrothorax, and unilateral involvement are strongly suggestive of previous tuberculosis [3] (Fig. 3). Chronic Persistent Pleural Effusion Tuberculous pleuritis may progress to chronic persistent pleural effusion or tuberculous empyema, which may be defined as persistent grossly purulent pleural fluid containing numerous tubercle bacilli [4]. Chronic persistent effusion is often asymptomatic and sometimes does not become apparent until many years after the episode of acute pleurisy. Chronic persistent effusion should be suspected if pleural thickening is in excess of 2 cm or if more than one linear shadow is visible running parallel to the inner chest wall on chest radiographs [5]. CT shows a loculated pleural fluid collection in association with pleural thickening and calcifications (Figs. 4 and 5). Chronic tuberculous empyema may either decompress through the chest wall, in which case it is called empyema necessitatis, or communicate with the bronchial tree, in which case a bronchopleural fistula results [5]. Empyema Necessitatis Empyema necessitatis, another wellknown complication of tuberculous pleuritis, 1 Department of Diagnostic Radiology, College of Medicine, Korea University, Korea University Guro Hospital, 80 Guro-dong, Guro-ku, Seoul , Korea. ddress correspondence to E.-Y. Kang. 2 Department of Radiology, Holy Family Hospital, Catholic University, Sosa-2-dong, Wonmi-gu, Pucheon city, Kyunggi-do , Korea. JR 2001;176: X/01/ merican Roentgen Ray Society Pictorial Essay JR:176, February

2 Choi et al. Fig. 1. Pleural thickening in 64-year-old man diagnosed with tuberculous pleuritis 3 years earlier. CT scan shows diffuse pleural thickening with areas of calcifications (arrows) in right hemithorax. 4 Fig. 2. Fibrothorax in 25-year-old woman. Radiographs of chest (not shown) obtained 6 months earlier revealed incidental abnormalities. CT scan shows extensive pleural thickening encompassing right hemithorax, which is decreased in volume. Fig. 3. Fibrothorax in 74-year-old man. CT scan shows extensive pleural thickening with calcifications in left hemithorax. Note loss of volume. lso, note adjacent rib hypertrophy and prominent epipleural fat pads (arrows), suggesting chronic benign pleural disease. 5 Fig. 4. Chronic tuberculous empyema in 66-year-old man diagnosed with tuberculous pleuritis 23 years earlier. CT scan obtained at level of lower thorax shows large loculated pleural fluid collection in right lower lateral hemithorax. Note surrounding pleural thickening and calcifications. Fig. 5. Chronic persistent pleural effusion in 40-year-old man. CT scan shows lenticular-shaped chronic loculated pleural effusion enclosed by calcified pleural layers in left lateral hemithorax. Note loculated fluid is near soft-tissue density (arrow), indicating chronicity of loculated content. 442 JR:176, February 2001

3 is formed by breakage of the tuberculous empyema through the parietal pleura for spontaneous discharge of its contents. The most common site of empyema necessitatis is subcutaneous tissue of the chest wall, but other sites include the esophagus, breast, retroperitoneum, flank, groin, pericardium, and vertebral column [6]. CT can lead to a diagnosis of empyema necessitatis by allowing simultaneous visualization of intrathoracic and extrathoracic lesions. CT findings include well-demarcated, thickwalled fluid collections in intrathoracic and extrathoracic locations [6] (Figs. 6 and 7). fistulous track between a pleural fluid collection and an extrathoracic fluid collection is often revealed on CT. Findings of empyema necessitatis CT of differ Tuberculous from those Pleuritis associated with musculoskeletal tuberculous infection involving rib, costal cartilage, sternum, and vertebra by the absence of bony or costal cartilage destruction and by the main location of the lesion. ronchopleural Fistula bronchopleural fistula is a direct communication between the pleural cavity and the bronchial tree or the lung parenchyma and may develop either during the active stage of the tuberculous infection or during a quiescent phase Fig. 6. Empyema necessitatis in 23-year-old man. and, CT scans reveal thick-walled, bilobed fluid collection involving both pleural cavity () and adjacent chest wall () without adjacent rib destruction. Direct communication between pleural (arrows, ) and chest wall fluid collection (arrows, ) is not shown on this CT scan. Patient had history of tuberculous pleuritis 5 years ago and presented with chest pain of 1 2 months duration. He underwent surgery and no rib destruction was found, consistent with findings on CT. many years later [7] as another chronic complication of tuberculous pleuritis. Chest radiographs are valuable not only for suggesting the possibility of a bronchopleural fistula, but also for monitoring the efficacy of therapy. The fistula is almost never directly seen but is suggested on chest radiographs [8]. CT is known to be the imaging technique of choice for visualization and characterization of bronchopleural fistulas [8]. CT findings include air and fluid collections in the pleural space with or without evidence of a communication or tract from an airway or the lung parenchyma to the pleural space [8] (Figs. 8 10). Fistulas may be shown as focal areas of low-attenuation Fig. 7. Empyema necessitatis in 25-year-old man. CT scan shows bilobed fluid collection along pleura and another unilocular fluid collection along adjacent outer chest wall (arrows) in right hemithorax. Center of fluid collections is located in intercostal space, and no definite evidence of rib destruction is present. t surgery, no evidence of rib destruction was found, consistent with CT findings. Fig. 8. ronchopleural fistula in 57-year-old man diagnosed with tuberculous pleuritis 3 years earlier. and, CT scans obtained at lung window setting reveal extensive nodular pleural thickening (arrows, ) extending for more than two thirds of circumference of right hemithorax () and allow direct visualization of fistula between bronchus and pleural cavity (arrow, ). ctive cavitary pulmonary tuberculosis is noted in left lung, which suggests cause of bronchopleural fistula is reactivated tuberculosis. JR:176, February

4 C Choi et al. Fig. 9. ronchopleural fistula in 68- year-old man diagnosed with tuberculous pleuritis 20 years earlier. t presentation, patient had known about his tuberculous empyema for 6 years but had refused treatment. and, CT scans obtained at lung () and soft-tissue () window settings at level of mid chest reveal extensive parietal and visceral pleural thickening and calcification with loculated pneumothorax in right hemithorax. lso note loss of volume of hemithorax. 444 JR:176, February 2001 D Fig. 10. ronchopleural fistula in 56-year-old man with history of multidrug-resistant tuberculosis. and, Initial CT scans obtained at mediastinal () and lung () window settings show extensive pleural thickening, calcifications in visceral and parietal pleurae, air fluid level (arrowheads, ) within pleural space, and minimal peripheral lung opacity, and findings suggestive of bronchiectasis (arrow, ) and atelectasis in adjacent lung. C and D, Follow-up CT scans obtained at mediastinal (C) and lung (D) window settings after 13 months show more extensive pleural thickening, calcifications, increased lung opacity, and atelectasis with bronchiectasis in adjacent lung parenchyma.

5 CT of Tuberculous Pleuritis Fig. 11. denocarcinoma associated with chronic tuberculous empyema of 30 years duration in 69-year-old man. and, CT scans of right lower hemithorax show soft-tissue mass lesion (arrows, ), which extends to posterior chest wall with adjacent rib destruction and is enhanced heterogeneously (). Note adjacent extensive pleural thickening and calcifications. lung consolidation that appear to communicate directly with an empyema or an obvious disruption of the visceral pleura (Fig. 8). In one study, a fistula was directly visualized on CT in 10 of 20 patients with possible bronchopleural fistulas [8]. Peripheral bronchopleural fistulas have been described as most evident in the presence of chronic inflammatory changes that lead to bronchiectasis or bronchiolectasis, which are depicted better on thin-section CT [8]. Identification of a fistula helps in planning treatment [9]. Malignancy of the Pleura The occurrence of malignant neoplasm is a relatively rare but critical complication of chronic tuberculous empyema. lthough the pathogenesis of this entity remains undetermined, chronic inflammation is considered the most important factor. Pathologic cell types of malignancy associated with longstanding empyema are variable and include malignant lymphoma, squamous cell carcinoma, mesothelioma, malignant fibrous histiocytoma, sarcoma, and hemangioendothelioma [10]. In a study by Minami et al. [10], who reviewed radiologic findings of six cases of malignancy associated with chronic empyema, the following retrospective findings on conventional chest radiographs were suggestive of malignancy: increased opacity in the thoracic cavity; soft-tissue bulging, unsharpness of fat planes in chest walls, or both; destruction of bone near empyema; extensive medial deviation of the calcified pleurae; and new occurrence of an air fluid level in the empyema cavity. CT can reveal an abnormal mass with soft-tissue attenuation around the empyema and usually contrast enhancement in the mass [10] (Fig. 11). In a patient with chronic empyema, a baseline CT scan is recommended to understand abnormal findings on chest radiographs and follow-up studies. Chronic complications should be watched for, and in patients with suspected malignancy, further radiologic evaluation with CT and MR imaging is recommended. References 1. Fraser RS, Müller NL, Colman N, Pare PD. Fraser and Pare s diagnosis of diseases of the chest, 4th ed., vol. 4. Philadelphia: Saunders, 1999: Sahn S. The pleura. m Rev Resir Dis 1988;138: Müller NL. Imaging of the pleura. Radiology 1993; 186: Hulnick DH, Naidich DP, McCauley DI. Pleural tuberculosis evaluated by computed tomography. Radiology 1983;149: Schmitt WGH, Hubener KH, Rucker HC. Pleural calcification with persistent effusion. Radiology 1983;149: Glicklich M, Mendelson DS, Gendal ES, Teirstein S. Tuberculous empyema necessitatis: computed tomography findings. Clin Imaging 1990;14: Donnath J, Khan F. Tuberculous and posttuberculous bronchopleural fistula: ten year clinical experience. Chest 1984;86: Stern EJ, Sun H, Haramati L. Peripheral bronchopleural fistulas: CT imaging features. JR 1996;167: Westcott JL, Volpe JP. Peripheral bronchopleural fistula: CT evaluation in 20 patients with pneumonia, empyema, or postoperative air leak. Radiology 1995; 196: Minami M, Kawauchi N, Yoshikawa K, et al. Malignancy associated with chronic empyema: radiologic assessment. Radiology 1991;178: JR:176, February