Sonographic appearances in transudative pleural effusions: not always an anechoic pattern

Pleural effusion patterns in sonographic appearances can be subclassified as anechoic, complex nonseptated, complex septated and homogeneously echogenic. Previous studies have suggested that transudates are usually anechoic; however, in daily practice we find frequently that heterogeneous echogenic material is present in transudative pleural effusions. This clinical study was to re-evaluate the sonographic appearances of transudative pleural effusions. A total of 127 patients with transudative pleural effusion that met Light's criteria ([1] a pleural fluid-serum protein ratio of <0.5, [2] a pleural fluid-serum lactate dehydrogenase [(LDH] ratio of <0.6 and [3] a pleural fluid LDH of less than two thirds of the upper limit of normal for serum LDH) and clinical presentations were enrolled. Results showed that transudative pleural effusions had the following sonographic appearances: an anechoic pattern in 45% (57/127) and a complex nonseptated pattern in 55% (70/127). There was no complex septated or homogenously echogenic pattern. In conclusion, sonographic presentations in transudative pleural effusions are not always in an anechoic pattern. If an afebrile patient without infectious symptoms/signs has bilateral pleural effusion compatible with transudate of Light's criteria, treat the underlying problems and ignore the complex nonseptated sonographic appearance. (E-mail: hsuwh@www.cmuh.org.tw).     

Sonographic septation in lymphocyte-rich exudative pleural effusions: a useful diagnostic predictor for tuberculosis.

OBJECTIVE: The purpose of this study was to evaluate the role of the sonographic features of lymphocyte-rich exudative pleural effusions in the differential diagnosis of tuberculosis and lung cancer in an area with a high incidence of tuberculosis. METHODS: Medical records of patients undergoing chest sonography between January 2003 and June 2005 (30 months) were reviewed retrospectively. The enrolled patients included 73 with lung cancer-related pleural effusions and 93 with tuberculous pleural effusions. The sonographic appearances of the pleural effusions were defined in terms of 4 patterns: anechoic, homogeneously echogenic, complex septated, and complex nonseptated. RESULTS: Among the 73 lung cancer-related pleural effusions, there were sonographic appearances of an anechoic pattern in 11% (8/73), a complex septated pattern in 4% (3/73), and a complex nonseptated pattern in 85% (62/73). In 93 tuberculous pleural effusions, there were sonographic appearances of an anechoic pattern in 12% (11/93), a complex septated pattern in 47% (44/93), and a complex non-septated pattern in 41% (38/93). Apparently, a complex septated pattern in the sonographic appearance of lymphocyte-rich pleural effusions is a useful diagnostic predictor for differentiating tuberculosis from lung cancer (95% confidence interval, -0.57 to -0.29). If we define the complex septated pattern in the sonographic appearance of lymphocyte-rich exudative pleural effusions as a predictor for tuberculous pleural effusions, we can achieve sensitivity, specificity, positive predictive value, negative predictive value, and positive likelihood ratio values of 47%, 96%, 94%, 59%, and 12, respectively. CONCLUSIONS: A complex septated pattern in the sonographic appearance is a useful predictor of tuberculosis in lymphocyte-rich exudative pleural effusions.     

Echographic appearance of the right hemidiaphragm.

In a prospective evaluation of the right upper quadrant in 100 consecutive healthy subjects, three echogenic lines were visualized in the right posterior, superior, and lateral aspects of the abdomen in the region of the right hemidiaphragm in approximately 80 per cent. A retrospective review was made of the sonograms of 33 patients with right pleural effusions alone, 14 patients with ascites alone, and ten patients with combined ascites and pleural effusions. Analysis of the number of echogenic lines seen in the region of the right hemidiaphragm and their relationship to the gas reverberation artifact suggests that two of the three lines seen in scans of normal subjects represent actual structures (diaphragm--liver capsule complex and lung--visceral pleura an in-vitro model constructed to simulate the liver, diaphragm, lung, and pleural effusion support the hypothesis that the lung and not the diaphragm is the mirror of the right upper quadrant.     

Chest sonography versus lateral decubitus radiography in the diagnosis of small pleural effusions

PURPOSE: The aim of this prospective study was to assess the value of chest sonography in the radiologic diagnosis of small pleural effusions (relative to expiratory lateral decubitus radiography) and to suggest gray-scale sonographic criteria for detecting the presence of small pleural effusions. METHODS: Patients referred for abdominal or chest sonographic evaluation for various reasons were also examined for sonographic features of pleural effusion from May 1, 1997, until January 31, 2000. Patients who had evidence of small pleural effusions were included. Patients with no such evidence served as a control group. Subsequently, all patients underwent erect posteroanterior and expiratory lateral decubitus chest radiography. RESULTS: On chest sonography, 52 patients were found to have small pleural effusions. The control group consisted of 17 patients. The mean thickness of the pleural effusion was 9.2 mm on sonography and 7.6 mm on expiratory lateral decubitus radiography (p < 0.01). Compared with radiologic examination, chest sonography had a positive predictive value of 92% in the diagnosis of small pleural effusions in our study population. CONCLUSIONS: Chest sonography showed a high degree of accuracy relative to that of lateral decubitus chest radiography in the diagnosis of small pleural effusions, which appeared as thin (usually 15 mm thick or less) anechoic areas that changed shape with the phases of respiration.     

Sonographic imaging of the pleura: nearly 30 years experience

Objective: The potentials of sonography of the pleura and pleural diseases and the evaluation of sonography in comparison with competitive imaging methods are reviewed.Methods and results: In detecting pleural effusions, sonography is superior to radiography. Also, the estimation of pleural effusion volume is more accurate by ultrasound than by chest film. Whereas echogenic pleural effusions are almost always exudates, echofree fluid collections may be either transudates or exudates. Thoracocentesis with sonographical guidance is less complicated and safer than when conventionally performed. Pleural thickening in pleurisy is rare. Pleural empyemas often manifest themselves with a bulky echopoor capsule and echogenic pus. Pleural metastases are singular or multiple nodular lesions. Mesotheliomas occur as singular tumors, more often as diffuse spreading thickening of the pleura with large effusions. Local infiltration of lung tumors into the pleura and transdiaphragmatic growth of mesotheliomas are assessed better by ultrasound than by computed tomography. Diagnostic use of ultrasound in severely ill patients at intensive care units is advantageous because of its easy bed-side application and its superior results in detecting effusions and underlying causes.Conclusion: Ultrasound is not only complementary to radiological investigations of the chest but often provides better results, particularly in pleural diseases. Sonography, therefore, should be the first imaging examination method after chest radiography in presumed pleural disease.     

Infectious mononucleosis with pleural effusion

We have described a 10-year-old child in whom a pleural effusion complicated an otherwise typical case of IM. Although rare, pleural effusions are a possible complication of infectious mononucleosis, and IM should be considered in the differential diagnosis of pleural effusions in children.     

Sonographic findings in grade III dengue hemorrhagic fever in adults

PURPOSE: Sonography has been used to evaluate children with dengue hemorrhagic fever, but to our knowledge no such studies have been conducted with adults. We present the sonographic findings in 40 adults with severe (grade III) dengue hemorrhagic fever (DHF). METHODS: Forty patients (30 men and 10 women, aged 16-65 years) given a presumptive diagnosis of grade III dengue hemorrhagic fever during a documented regional epidemic underwent abdominal sonography. Ten also underwent chest radiography. Serologic confirmation was obtained in 5 patients, and in the rest the diagnosis was based on epidemiologic and clinical findings. RESULTS: Sonographic findings included pleural effusion in 21 patients (53%), thickening of the gallbladder wall in 17 (43%), and mild ascites in 6 (15%). These findings were similar to those of previous studies of severe DHF in children, although the incidence of pleural effusion and ascites was slightly lower in our series. Neither pleural effusion nor ascites was apparent on clinical examination. Of the 10 patients who underwent both sonography and chest radiography, sonography detected pleural effusion in all 10, whereas radiography detected it in only 3. CONCLUSIONS: Sonographic findings in DHF in adults (pleural effusions, ascites, and gallbladder wall thickening) were similar to those described for children but seem to be of lesser severity. Abdominal sonography is a useful diagnostic tool for confirming suspected cases of DHF. Sonography was found to be superior to chest radiography in detecting pleural effusions in the 10 patients in whom radiographs were available.     

Pleural diseases.

In the United States, approximately one million patients each year develop a pleural effusion. Pleural effusions have classically been divided into transudative and exudative pleural effusions. A transudative pleural effusion occurs when the systemic factors influencing pleural fluid formation and reabsorption are altered so that pleural fluid accumulates; an exudative pleural effusion occurs when the local factors influencing pleural fluid formation and reabsorption are altered, allowing accumulation of pleural fluid. The leading causes of transudative pleural effusions are left ventricular failure and cirrhosis with ascites. The leading causes of exudative pleural effusions are pneumonia, malignancy, and pulmonary embolization. Transudative pleural effusions can be differentiated from exudative pleural effusions by measurement of the pleural fluid protein and lactic dehydrogenase (LDH) levels. The ratio of the pleural fluid protein to the serum protein is less than 0.5, the ratio of the pleural fluid LDH to the serum LDH is less than 0.6, and the absolute value of the pleural fluid LDH level is less than two thirds of the upper normal limit for serum with transudative pleural effusions while at least one of these criteria is not met with exudative effusions. Most patients who have a pleural effusion with congestive heart failure have left ventricular failure. It is believed that the transudation of the pulmonary interstitial fluid across the visceral pleura overwhelms the capacity of the lymphatics to remove the fluid. Most patients with cirrhosis who have a pleural effusion also have ascites. It is also believed that the pleural effusions form when fluid moves directly from the peritoneal cavity into the pleural cavity through pores in the diaphragm. Approximately 40% of patients with pneumonia will have a pleural effusion. If these patients have a significant amount of pleural fluid, a diagnostic thoracentesis should be performed. Chest tubes should be inserted if the pleural fluid is gross pus, if the Gram stain of the pleural fluid is positive, if the pleural fluid glucose level is below 40 mg/dl, or if the pleural fluid pH level is less than 7.00. If drainage with the chest tubes is unsatisfactory, either streptokinase or urokinase should be injected intrapleurally. If drainage is still unsatisfactory, a decortication should be considered. The three leading malignancies that have an associated pleural effusion are breast carcinoma, lung carcinoma, lymphomas and leukemias. The diagnosis of pleural malignancy is made most commonly with pleural fluid cytology; in recent years immunohistochemical tests have proved invaluable in differentiating benign from malignant pleural effusions.(ABSTRACT TRUNCATED AT 400 WORDS)     

Pleural effusion: diagnostic value of measurements of PO2, PCO2, and pH

A review of the literature suggests that the measurement of the partial pressure of oxygen (PO2) and carbon dioxide (PCO2) and pH may provide additional diagnostic, therapeutic, and prognostic information in the management of pleural effusions. Parapneumonic effusions with a pH less than 7.2 indicate an impending empyema requiring tube thoracostomy in more than 98% of cases. A distinction between a tuberculous pleural effusion and a malignant pleural effusion of recent onset (less than two months) can frequently be made by measuring the pleural fluid pH. In 100% of reported cases, tuberculous pleural effusions have a pleural fluid pH less than 7.4, whereas over 60% of recent malignant effusions have a pleural fluid pH greater than 7.4. Generally, measurements of PO2 and PCO2 have little discriminatory value in determining cause or proper management of pleural effusions. It is recommended that proper anaerobic collection of pleural fluid for pH measurements be obtained routinely in all pleural effusions of unknown cause.     

Ascites or pleural effusion? CT and ultrasound differentiation

The differentiation of fluid immediately above the diaphragm, i.e., pleural effusion, from subdiaphragmatic fluid, i.e., ascites, can be difficult. Freely mobile pleural effusions are easily proven with decubitus chest films, but loculated subpulmonic effusions can mimic intraabdominal fluid. The simultaneous presence of both ascites and pleural effusion is difficult to identify with plain radiographs. Both computed tomography (CT) and ultrasound (US) can be used to differentiate ascites from pleural effusion. Four criteria have been described to differentiate ascites from pleural effusion by CT. These four signs (the diaphragm sign, the displaced crus sign, the interface sign, and the bare area sign) are reliable when only one abnormal fluid collection is present. When both a pleural effusion and ascites are present, none of these criteria can reliably identify both fluid collections. The combined use of the four criteria, however, leads to a correct identification of abnormal fluid collections in the region of the diaphragm. US examination can differentiate ascites from pleural effusion using three of the above-mentioned signs (the diaphragm sign, the displaced crus sign, and the bare area sign). We will review the four signs and discuss the limitation of these signs in clinical practice. A thorough understanding of these CT and US criteria will allow for accurate identification of all juxtadiaphragmatic fluid collections.     

Distribution of pleural effusion in congestive heart failure: what is atypical?

OBJECTIVES: This study was performed to determine the distribution of pleural effusion between the right and left hemithorax in patients with uncomplicated congestive heart failure, and to determine whether left-sided pleural effusion actually constitutes an atypical distribution in congestive heart failure. METHODS: The study group consisted of 120 consecutive patients with both clinical and radiographic evidence of uncomplicated congestive heart failure, and whose chest radiographs at the time of presentation also showed evidence of pleural effusion. The presence or absence of pleural effusion in the right and left hemithorax was recorded for each case, as was the size of each pleural effusion, and the distribution of pleural effusion in these 120 patients was entered into a 2 x 2 table and analyzed by chi2 analysis. RESULTS: There were 207 total pleural effusions, with 105 on the right and 102 on the left. Isolated right-sided pleural effusions occurred in 18 patients, there were bilateral pleural effusions larger on the right than the left in 25, there were bilateral pleural effusions of roughly equal size on each side in 36, there were bilateral pleural effusions larger on the left side than the right in 26, and there were isolated left-sided pleural effusions in 15. The difference was not statistically significant (chi2 = 0.316; P < or = 1.0). CONCLUSIONS: Left-sided pleural effusion is not an atypical finding in congestive heart failure and is not, in and of itself, an indication for further clinical or imaging evaluation.     

Pleural effusions in right-sided endocarditis: characteristics and pathophysiology.

The incidence, characteristics, and pathogenesis of pleural effusions in patients with right-sided endocarditis (RSE) are poorly defined. We have recently observed four patients with a history of intravenous drug abuse and bacteremia due to Staphylococcus aureus who had pleural effusions during an episode of RSE. We report the pleural fluid characteristics of five effusions in these four patients and attempt to define the pathogenesis of each. We found that (1) an exudative, sterile, serosanguineous, or bloody effusion is common in RSE, (2) empyema occurred in only one patient, and (3) transudative effusions due to CHF were not observed. Possible mechanisms of pleural fluid formation in RSE include parapneumonic effusion, septic pulmonary emboli with or without infarction, and empyema. Congestive heart failure does not appear to be a common cause of pleural effusion in pure right-sided endocarditis.     

胸腔内注入尿激酶治疗结核性包裹和肥厚性胸腔积液的临床价值

目的：探讨胸膜腔内注入尿激酶(urokinase，UK)对结核性渗出性胸膜炎所致胸膜肥厚和粘连包裹性积液的影响。方法：30例常规抽液不能抽及．B超和／或胸部CT提示为包裹性积液、胸膜肥厚的患．每次抽液后胸腔内注入尿激酶10万IU。全身正规抗结核治疗。结果：胸腔内注入尿激酶后，浓稠的纤维蛋白被溶解，抽液明显畅通，胸水量增多，明显吸收占90％(27／30)，部分吸收占10％(3／30)。结论：在正规抗结核治疗下．配合胸腔内注入尿激酶治疗结核性包裹和肥厚性胸腔积液可增加引流量、减少包裹量、减轻胸膜肥厚、改善肺功能。     

Association between inflammatory mediators and the fibrinolysis system in infectious pleural effusions

The response of the fibrinolytic system to inflammatory mediators in empyema and complicated parapneumonic pleural effusions is still uncertain. We prospectively analysed 100 patients with pleural effusion: 25 with empyema or complicated parapneumonic effusion, 22 with tuberculous effusion, 28 with malignant effusion and 25 with transudate effusion. Inflammatory mediators, tumour necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8) and polymorphonuclear elastase, were measured in serum and pleural fluid. Fibrinolytic system parameters, plasminogen, tissue-type plasminogen activator (t-PA) and urokinase PA, PA inhibitor type 1 (PAI 1) and PAI type 2 concentrations and PAI 1 activity, were quantified in plasma and pleural fluid. The Wilcoxon signed-rank test was used to compare plasma and pleural values and to compare pleural values according to the aetiology of the effusion. The Pearson correlation coefficient was used to assess the relationship between fibrinolytic and inflammatory markers in pleural fluid. Significant differences were found between pleural and plasma fibrinolytic system levels. Pleural fluid exudates had higher fibrinolytic levels than transudates. Among exudates, tuberculous, empyema and complicated parapneumonic effusions demonstrated higher pleural PAI levels than malignant effusions, whereas t-PA was lowest in empyema and complicated parapneumonic pleural effusions. PAI concentrations correlated with TNF-alpha, IL-8 and polymorphonuclear elastase when all exudative effusions were analysed, but the association was not maintained in empyema and complicated parapneumonic effusions. A negative association found between t-PA and both IL-8 and polymorphonuclear elastase in exudative effusions was strongest in empyema and complicated parapneumonic effusions. Blockage of fibrin clearance in empyema and complicated parapneumonic effusions was associated with both enhanced levels of PAIs and decreased levels of t-PA.     

Role of biochemical tests in the diagnosis of exudative pleural effusions

OBJECTIVES: To examine the diagnostic utility of pleural adenosine deaminase (PADA), pleural lactate dehydrogenase (PLDH), and several other biochemical tests in bronchogenic carcinoma and malignant mesothelioma, and to compare biochemical characteristics of their fluid with nonmalignant pleural effusions. DESIGN AND METHODS: This study consisted of 226 patients diagnosed with malignant (75), tuberculous (65), and parapneumonic pleural effusions (86). We examined the following biochemical parameters in the pleural fluid and serum: adenosine deaminase, lactate dehydrogenase, glucose level, protein level, pleural fluid/serum ADA ratio (P/S ADA), P/S LDH ratio, and P/S protein ratio. RESULTS: Parapneumonic pleural effusions had a significantly higher level of PLDH and of P/S LDH than malignant and tuberculous pleural effusions (P = 0.000), and malignant pleural effusions had a higher level of PLDH than tuberculous pleural effusions. Tuberculous and parapneumonic effusions had significantly higher levels of PADA than those of malignant effusions (P = 0.000). When the 54 patients having bronchogenic carcinoma were compared to the remaining 21 mesothelioma patients, the former had a lower median level of PADA (P = 0.001) with a higher level of PLDH (P = 0.05). CONCLUSION: Our results show that high pleural LDH and low PADA levels are suggestive of pleural effusion due to bronchogenic carcinoma, whereas high levels of PADA alone can be indicative of tuberculous pleural effusion and high levels of both markers can show complicated parapneumonic effusions or empyema.     

血管内皮生长因子、端粒酶、腺苷脱氨同工酶联合检测在胸腔积液鉴别诊断中的价值

目的探讨血管内皮生长因子(VEGF)、端粒酶、腺苷脱氨同工酶(ADA)联合检测在良恶性胸腔积液中的诊断价值。方法应用ELISA法检测VEGF的浓度、采用聚合酶联反应-酶联免疫吸附分析法(PCR-ELISA)检测胸腔积液端粒酶活性、用比色分析法检测胸腔积液ADA含量。结果恶性及结核性胸腔积液组VEGF值分别为(327±152)pg/L和(35±15)pg/L,结核组显著低于恶性组(P<0.01)。恶性胸腔积液中端粒酶活性显著高于结核性胸腔积液(P<0.01)。结核性胸液组ADA含量为(45.78±12.78)u/L,高于恶性胸液组(13.56±4.91)u/L,两者间差异有统计学意义。结论检测胸腔积液端粒酶、VEGF和ADA同工酶对癌性胸腔积液的诊断均有一定的价值,联合检测综合诊断能提高诊断准确率。     

Transthoracic Ultrasonography in Predicting the Outcome of Small-Bore Catheter Drainage in Empyemas or Complicated Parapneumonic Effusions

Thoracic sonography has been advocated as being complementary to small-bore catheter drainage in pleural effusions. However, it is not known whether the initial sonographic appearances of empyemas or complicated parapneumonic effusions (CPPEs) can predict the outcomes of small-bore catheter drainage for these pleural insults. This retrospective study investigated the outcomes of patients who had been diagnosed with empyema and CPPE and had received ultrasound-guided small-bore catheter (size from 12F to 16F) drainage in a tertiary university hospital from September 2005 to August 2007. Patients were excluded when empyemas or CPPEs were traumatic, they were less than 18 years old or their charts were incomplete. We evaluated 141 small-bore catheters in 70 patients with empyemas and 71 patients with CPPEs over a two-year period. The mean age was 58 ± 15 y and the male gender was more frequent (112 men, 79%). The overall successful rate of small-bore catheter drainage in empyemas or CPPEs was 63% (89/141). The sonographic appearances of these empyemas or CPPEs exhibited a complex septated pattern in 57% (81/141) of patients and a complex nonseptated pattern in 43% (60/141) of patients. The success rate in a complex nonseptated sonographic pattern was significantly higher than in a complex septated sonographic pattern (48/60, 80% vs. 41/81, 51%, respectively; p = 0.001). Moreover, patients with complex septated sonographic patterns also had higher intensive care unit admission rates compared with nonseptated sonographic patterns (22/81, 27%, vs. 8/60, 13%, respectively; p = 0.0047), as well as infection-related mortality rates (17/81, 21% vs. 4/60, 7%, respectively; p = 0.018). The appearance of sonographic septation is a useful sign to help predict the outcome of small-bore catheter drainage in cases of empyemas or CPPEs. Patients with a complex septated sonographic pattern have a poorer prognosis for a successful outcome, higher ICU admission rate and a higher mortality rate.     

Incidental Detection of Malignant Pleural Effusion on Sestamibi Myocardial Perfusion Scan

Incidentally the diagnosis of pleural effusions can be made with scintigraphic studies. We report a case of incidental detection of pleural effusion in sestamibi myocardial perfusion scan. A 64-year-old man with a history of chest pain was referred for Sestamibi myocardial perfusion scintigraphy. The review of cine data revealed an area of radiotracer accumulation in the left hemithorax. Subsequent chest X-ray and computed tomography revealed a relatively massive pleural effusion. Microscopic evaluation confirmed the malignant nature of pleural effusion, the origin of which was an ipsilateral pulmonary adenocarcinoma. As to our knowledge, it is the first report of sestamibi uptake in pleural effusion fluid. In our opinion, this finding could be explained by radiotracer uptake in the malignant component of the effusion. Reporting of these incidental findings could be important and sometimes can be resulted in determining previously unknown pathologies.     

Nodular Fasciitis: Sonographic–Pathologic Correlation

We evaluated nodular fasciitis (NF) in 19 patients, focusing on the correlation between its sonographic and histopathologic features. Sonograms were retrospectively reviewed, and the location, shape, margin, echogenicity, echogenic rim, peripheral hyper-echoic nodules, posterior enhancement and vascularity of the lesions were recorded. In the histopathologic analysis, three patterns—infiltrating, pushing border and well circumscribed—were identified, and culture-like tissue centers were classified according to the distribution of focal keloid-like collagen bundles: uneven or even. For the sonographic–pathologic correlation, most NF cases were inhomogeneously hypo-echoic and had an echogenic rim, with an infiltrating or pushing border pattern. In addition, all NF cases with the infiltrating pattern were observed to have peripheral hyper-echoic nodules in sonograms. Thus, echogenic rims may be associated with the peripheral adipose tissues in infiltrating pattern, and the degree of infiltration may be associated with specific sonographic features of NF.     

Pleural effusions in cardiovascular disease. Pearls for correlating the evidence with the cause

In patients with cardiomegaly and signs and symptoms compatible with CHF, unilateral right-sided or bilateral pleural effusions of similar size are likely to be due to left-sided CHF. Isolated right ventricular failure or chronic pulmonary hypertension is not usually associated with pleural effusions, and unrecognized or new-onset left ventricular dysfunction and other causes should be considered when a patient with cor pulmonale presents with a pleural effusion. Unilateral left-sided pleural effusions with cardiomegaly may be due to pericardial disease. Current hypotheses do not adequately explain the laterality of effusions in CHF or pericardial disease. Clinical and radiographic correlation is always required; however, the associations described occur often enough to make them useful in day-to-day clinical practice. When ascribing pleural effusions to CHF, clinicians must be sure the clinical signs and history "fit the picture," because pneumonia and pulmonary embolism may also cause pleural effusions in patients with heart failure. Typical pleural effusions in patients with uncomplicated CHF (demonstrated by small to medium-sized effusions and the absence of fever, leukocytosis, pleuritic chest pain, or marked asymmetry in bilateral effusions) do not require routine diagnostic thoracentesis for evaluation. A reasonable approach in such cases is treatment of the underlying CHF and follow-up radiography to monitor for resolution of the effusions. Prompt diagnostic thoracentesis is indicated whenever atypical features are present and other diagnoses are under consideration.