PleuralEffusions胸膜渗出中山大学内科学.ppt

Contents,Anatomy and Mechanism of pleural fluids turnover Etiology and pathogenesis of pleural effusions Clinical manifestations Radiographic Examination Approach to the patient with pleural effusions Management of patient with pleural effusions,1,Dr. Canmao xie,The pleural space is not really a space but rather a potential space between the lung and chest wall. It is a crucial feature of the breathing apparatus since pleurae serves as a coupling system between the lung and chest wall.,Introduction,2,Dr. Canmao xie,Introduction,There is normally a very thin layer of fluid (from 2 to 10 m thick) between the two pleural surfaces, the parietal pleura and visceral pleura. The pleural space and the fluid within it are not under static conditions. During each respiratory cycle the pleural pressures and the geometry of the pleural space fluctuate widely. Fluid enters and leaves the pleural space constantly .,3,Dr. Canmao xie,Anatomy of the Pleural Space,The serous membrane covering the lung parenchyma is called the visceral pleura. The remainder of the lining of the pleural cavity is designated the parietal pleura. The parietal pleura receives its blood supply from the systemic capillaries. The visceral pleura is supplied predominantly by branches of the bronchial artery in humans.,Dr. Canmao xie,4,SC: Systemic capillaries PC: Pulmonary capillaries,The lymphatic vessels in the parietal pleura are in direct communication with the pleural space by means of stomas. These stomas are the only route through which cells and large particles can leave the pleural space. Although there are abundant lymphatics in the visceral pleura, these lymphatics do not appear to participate in the removal of particulate matter from the pleural space.,Dr. Canmao xie,5,SC: Systemic capillaries PC: Pulmonary capillaries,Anatomy of the Pleural Space,Figure 1. Anatomy of the pleural space SC: Systemic capillaries PC: Pulmonary capillaries,6,Dr. Canmao xie,stomas,stomas,electronic microscopy,Figure 2. pleural fluids turnover PF enter the pleural space through parietal & visceral pleurae, And leave pleural space through lymphatics in parietal pleura,Dr. Canmao xie,The passage of protein-free liquid across the pleural membranes is dependent on the hydrostatic and oncotic pressures across them. When the capillaries in the parietal pleura are considered, it can be seen that the net hydrostatic pressure favoring the movement of fluid from these capillaries to the pleural space is the systemic capillary pressure (30cm H2O) minus the negative pleural pressure (-5cm H2O) or 35cm H2O. Opposing this is the oncotic pressure in the blood (34cm H2O) minus the oncotic pressure in the pleural fluid (5 cm H2O), or 29cm H2O. The resulting net pressure differences of 6 cm H2O (35-29) favors movement of fluid from the parietal pleura into the pleural space.,Mechanism of pleural fluids turnover,8,Dr. Canmao xie,Figure. Diagrammatic representation of the pressures involved in the formation and absorption of pleural fluid.,Parietal Pleura Visceral Pleura Space Pleura Hydrostatic Pressure +30 - 5 + 24 35 29 6 0 Net 29 29 + 34 + 5 +34 Oncotic Pressure,9,Dr. Canmao xie,Mechanism of pleural fluids turnover,The net rate of pleural fluid formation in animals with thick pleura is approximately 0.01 ml/kg/hr or 15 ml per 24 hr. Normally, the pleural space is maintained nearly fluid free because the filtered fluid is removed from the pleural space by the pleural lymphatics, which can remove over 0.20 ml/kg/hr .,10,Dr. Canmao xie,Pathophysiology,Pleural fluid will accumulate when the rate of pleural fluid formation is greater than the rate of pleural fluid removal by the lymphatics. Pleural effusions have classically been divided into Transudative exudative,11,Dr. Canmao xie,A transudative pleural effusion occurs when alterations in the systemic factors that influence pleural fluid movement result in a pleural effusion. Examples are elevated visceral pleural capillary pressure with left heart failure, elevated parietal pleural capillary pressure with right heart failure, and decreased serum oncotic pressure with the nephrotic syndrome, hepatic cirrhosis. In contrast, exudative pleural effusions occur when the pleural surfaces themselves are altered. Inflammation of the pleura, leading to increased protein in the pleural space, is the most common cause of exudative pleural effusions.,Dr. Canmao xie,12,Pathophysiology,Etiology and Pathogenesis,Many diseases can cause pleural effusions Elevated pleural capillary pressure, such as congestive heart failure, pericardial disease, increased blood volume, et al Elevated pleural permeability, such as pleural inflammation, neoplastic pleural disease (metastatic disease or mesotheliomas), pulmonary emboli, systemic lupus erythematosus (SLE), et al Decreased serum oncotic pressure, such as cirrhosis, nephrotic syndrome, myxedema, et al Dysfunction of parietal pleura lymphatics drainage Trauma, such as esophageal perforation, post-cardiac injury syndrome, et al,Dr. Canmao xie,Clinical Manifestations,The symptoms of a patient with a pleural effusion are to a large extent dictated by the underlying process causing the effusion. Many patients have no symptoms referable to the effusion when effusion is small. When symptoms are related to the effusion, they arise either from inflammation of the pleura or from compromise of pulmonary mechanics. Pleuritic chest pain is the usual symptom of pleural inflammation. Irritation of the pleural surfaces may also result in a dry, nonproductive cough. With larger effusions, dyspnea results from lung compression.,14,Dr. Canmao xie,Physical Examinations,Signs are closely correlated to the volume of pleural effusions. Physical examination of a patient with pleural effusion reveals :,Decreased or absent tactile fremitus, dullness to percussion Diminished breath sounds over the site of the effusion Bronchial breath sounds are frequently present immediately above the effusion,15,Dr. Canmao xie,Bronchial breath sounds,Diminished breath sounds,Radiographic Appearance,The first fluid accumulates in the lowest portion of the thoracic cavity, which is the posterior costophrenic angle. Therefore, the earliest radiologic sign of a pleural effusion is blunting of the posterior costophrenic angle on the lateral chest radiograph. If a posteroanterior radiograph is obtained with the patient lying on the affected side, free pleural fluid will gravitate inferiorly and a pleural fluid line will be visible.,16,Dr. Canmao xie,A posteroanterior and lateral chest radiograph of pleural effusion blunting of the posterior costophrenic angle,17,Dr. Canmao xie,Pleural fluid is said to be loculated when it does not shift freely in the pleural space as the patients position is changed. Loculated pleural effusions occur when there are adhesions between the visceral and parietal pleurae. Both ultrasound and computed tomography (CT) have proved useful in making this differentiation.,Dr. Canmao xie,18,Radiographic Appearance,Approach to the Patient with Pleural Effusion,There are many different diseases that can be associated with pleural effusion. When a pleural effusion is discovered, two questions need to be answered: a. Is the effusion a transudate (i.e., is it due to systemic factors) or is it an exudate (i.e., is it due to disease of the pleura itself)? b. If the effusion is an exudate, what is the disease responsible for its production? Answers to these two questions can only be obtained by examining the pleural fluid. Nearly every patient with a pleural effusion should have a diagnostic thoracentesis.,19,Dr. Canmao xie,Appearance of the Pleural Fluid,The gross appearance of the pleural fluid provides useful information. Odor of pleural fluid Putrid - probably anaerobic pleural infection Urine - probable urinothorax unless patient is uremic Bloody - obtain hematocrit (Hct), 50% of peripheral hematocrit - hemothorax,20,Dr. Canmao xie,Cloudy or turbid - either cells and debris or high lipid levels Post centrifugation If supernatant turbid, due to high lipid levels Turbid supernatant - measure pleural fluid triglyceride level Triglyceride level 110 mg/dl chylothorax Triglyceride level 250mg - pseudochylothorax 50 mg/dl Triglyceride level 110 mg/dl - obtain lipoprotein analysis Presence of chylomicrons - chylothorax,Appearance of the Pleural Fluid,21,Dr. Canmao xie,Separating exudates from transudates,Lights criteria (to fit one or more of the following three) : Pleural fluid protein/serum protein ratio 0.5 Pleural fluid LDH/serum LDH 0.6 Pleural fluid LDH 2/3 upper normal limit for serum LDH,22,Dr. Canmao xie,Dr. Light raised the Lights criteria when he was at age of 32,LDH=lactate dehydrogenase,23,Dr. Canmao xie,Routine tests on exudative pleural effusions,If the patient possibly has a transudative pleural effusion, it is most cost-effective to only measure the pleural fluid protein and LDH levels initially. If the effusion is transudative, additional tests provide no additional information and sometimes produce misleading positive results. Additional tests to consider ordering on exudative pleural fluids include smears and cultures for bacteria, cell count with differential, glucose levels, a pleural fluid markers for tuberculosis and pleural fluid cytology.,24,Dr. Canmao xie,Cell count and differential,The pleural fluid differential cell count is useful in the differential diagnosis of an exudative pleural effusion. The presence of predominantly neutrophils (50%) indicates that an acute process is affecting the pleura. The presence of predominantly mononuclear cells indicates a chronic process. The presence of predominantly small lymphocytes indicates that the patient most likely has malignancy, a pleural effusion post coronary artery bypass surgery or tuberculous pleuritis.,25,Dr. Canmao xie,Pleural fluid glucose levels,The presence of a low pleural fluid glucose concentration (60 mg/dl or 3.3mmol/L) indicates that the patient probably has a complicated parapneumonic or a malignant effusion. Less common causes of low glucose pleural effusions are hemothorax, tuberculosis and rheumatoid pleuritis.,26,Dr. Canmao xie,Pleural fluid LDH level,Although the pleural fluid LDH does not help differentiate various exudative pleural effusions, it is an indicator of the degree of pleural inflammation and should be measured each time pleural fluid is sampled from an undiagnosed pleural effusion. Pleural LDH500u/L indicates a possibility of neoplastic pleural disease or secondary pleural bacterial infection.,27,Dr. Canmao xie,Pleural fluid pH,If the patient has a parapneumonic or a malignant pleural effusion, a pleural fluid pH (using a blood gas machine) is indicated. A pleural fluid pH below 7.20 in patient with a parapneumonic effusion is an indicator for drainage of the effusions. A pleural fluid pH below 7.20 in a patient with a malignant pleural effusion indicates that the patients life expectancy is only about 30 days and that chemical pleurodesis is likely to be ineffective.,28,Dr. Canmao xie,Pleural fluid tests for malignancy,Cytologic examination of the pleural fluid is a fast, efficient and minimally invasive means by which this diagnosis can be established. There have been many studies evaluating the utility of tumor markers such as CEA, CA 15-3, CA 19-9, and ENOLAS If cutoff set high enough, there is no false positives, then it is very insensitive. In order to be useful, the tumor marker must be complimentary to the pleural fluid cytology The diagnostic GOLD standard for malignant pleural effusion. Since a blind needle biopsy of the pleura adds little to cytology in diagnosing pleural malignancy, thoracoscopy is the procedure of choice for the patient with suspected malignancy and negative cytology.,29,Dr. Canmao xie,Malignant effusions,30,Dr. Canmao xie,肺腺癌,患者男性，65岁。 因“反复胸痛5月，呼吸困难1月，加重1周” 入院。胸水CEA增高。,镜下见：脏、壁层胸膜间粘连带形成，壁层胸膜、膈面见弥漫性结节样新生物，部分表面覆盖白色坏死组织，右上叶后段斜裂缘见白色息肉样肿物，右下叶表面多发灰色斑状浸润。病理示腺癌。,Pleural fluid markers for tuberculosis,If tuberculous pleuritis is not treated, the effusion will resolve but pulmonary or extrapulmonary tuberculosis subsequently develops in more than 50%. Since less than 40% of patients with tuberculous pleuritis have positive pleural fluid cultures, alternative means such as the level of adenosine deaminase (ADA), gamma interferon or polymerase chain reaction (PCR) are used to establish the diagnosis. The pleural fluid ADA level above 45 IU/L is significant in establishing the diagnosis of tuberculous pleuritis.,32,Dr. Canmao xie,Parapneumonic Effusion,Any pleural effusion associated with bacterial pneumonia, lung abscess, or bronchiectasis is a parapneumonic effusion. A Gram-stain and bacterial culture (both aerobic and anaerobic) will identify infected pleural fluids. Effective antibiotics therapy is the key issue for controlling infection. If upon examination of the pleural fluid, any one of the following four conditions is met, chest tubes should be inserted immediately : 1. Gross pus is obtained on thoracentesis - empyema ; 2. The Gram stain of the pleural fluid is positive for organisms; 3. The pleural fluid glucose level is less than 40 mg/100 ml; 4. The pleural fluid PH is below 7.00.,33,Dr. Canmao xie,Tuberculous Pleural Effusions,At the onset of tuberculous pleuritis, most patients also have pleuritic chest pain. Tuberculosis toxic syndrome dry cough, low grade fever, night sweat and losing body weight. With a positive tuberculin skin test (PPD) and significantly high ADA level in pleural effusion. The fluid is invariably an exudate. Frequently the pleural fluid protein is over 50 g/L and this finding is very suggestive of tuberculous pleuritis. The differential white cell count reveals more than 80% lymphocytes. Pleural biopsy has its greatest utility in establishing the diagnosis of tuberculous pleuritis. The demonstration of granuloma in the parietal pleura is highly suggestive of tuberculous pleuritis. Caseous necrosis or acid-fast bacilli need to be demonstrated.,34,Dr. Canmao xie,Tuberculous Pleurisy,35,Dr. Canmao xie,Management of Tuberculous Pleural Effusions,Anti-tuberculosis chemotherapy: Adequate therapy for tuberculous pleuritis is a 9-month course of isoniazid and rifampin daily. The performance of the therapeutic thoracentesis is highly recommended as soon as the diagnosis is confirmed. The administration of corticosteroids will rapidly relieve the patients symptoms of pleuritic chest pain, malaise, an