Pleural effusion

Introduction to pleural effusion Normal people have 3 to 15 ml of liquid in the chest cavity, which acts as a lubricant during respiratory movement, but the amount of fluid in the pleural cavity is not fixed. Even in normal people, 500 to 1000 ml of liquid is formed and absorbed every 24 hours. The intrapleural injection is reabsorbed from the venous end of the capillaries, and the rest of the fluid is recovered from the lymphatic system to the blood, and the filtration and absorption are in dynamic equilibrium. If the dynamic balance is destroyed by systemic or local lesions, the pleural cavity fluid is formed too fast or absorbed too slowly, and pleural effusion (Pleuraleffusion, pleural fluid) is clinically produced. basic knowledge The proportion of illness: 0.0035% Susceptible people: no specific population Mode of infection: non-infectious Complications: pulmonary edema, shock, heart failure

Cause of pleural effusion

Increased hydrostatic pressure in the pleural capillaries (25%):

The increase of systemic hydrostatic pressure is the most important factor in the development of pleural effusion. For example, congestive heart failure or constrictive pericarditis can increase the hydrostatic pressure of systemic circulation and/or pulmonary circulation, and increase the pleural fluid filtration. Pleural effusion, simple systemic hydrostatic pressure increase, when the vena cava or azygotic vein is blocked, the pleural fluid exudation exceeds the visceral pleural effusion ability, resulting in pleural effusion, and most of these pleural effusions are leakage.

Increased pleural capillary permeability (20%):

Pleural inflammation or tissue infections adjacent to the pleura, pulmonary infarction or systemic disease involving the pleura can increase pleural capillary permeability, capillary cells, proteins and fluids infiltrate into the pleural cavity, and protein content in pleural fluid increases. The osmotic pressure of the pleural fluid colloid increases, further promoting the increase of pleural effusion, which is an exudate.

Plasma colloid osmotic pressure decreased (15%):

Protein loss diseases such as nephrotic syndrome, liver cirrhosis, chronic infection and other protein synthesis reduction or disorder diseases, plasma albumin decreased, plasma colloid osmotic pressure decreased, parietal pleural capillary fluid filtration increased, and visceral absorption decreased Or stop, forming a leaky pleural effusion.

Parietal pleural lymphatic drainage is blocked (15%):

The parietal pleural lymphatic drainage system (mainly lymphatic vessels) plays a role in the absorption of fluid in the thoracic cavity. When congenital abnormalities or tumor thrombi, parasitic occlusion, or trauma caused by lymphatic drainage, it is easy to produce high protein thoracic cavity. Exudate.

Injury pleural effusion (10%):

Trauma (such as esophageal rupture, thoracic duct rupture) or disease (such as thoracic aortic aneurysm rupture) and other reasons, bloody, purulent (secondary infection), chylothorax effusion, is an exudate.

Pleural effusion prevention

1. Active prevention and treatment of primary disease, pleural effusion is part of the chest or systemic disease, so active prevention and treatment of primary disease is the key to prevent this disease.

2, enhance physical fitness, improve disease resistance, and actively participate in a variety of appropriate physical exercise, such as Tai Chi, Tai Chi sword, Qigong, etc., to enhance physical fitness and improve disease resistance.

3, pay attention to life adjustment, residence should be kept dry, avoid wet and invasive, do not eat cold, do not overeating, keep the function of the spleen and stomach normal, after treatment, timely treatment, shelter from the cold, careful living, pleasant mood, to Get well soon.

Pleural effusion complications Complications pulmonary edema shock heart failure

Concurrent bacterial infection, pleural adhesions, anemia, shock, pulmonary edema, severe heart failure and renal failure.

Symptoms of pleural effusion Common symptoms Chest pain Breathing difficulties Chest tightness Breathing sounds weakened pleural friction sound Dry cough pleural pleural effusion Forced squatting Skin firming chest

1, cough, chest pain: often dry cough, with chest tingling, chest pain increased when coughing or deep breathing.

2, difficulty breathing: a small amount of fluid when the symptoms are not obvious, or slightly feeling chest tightness; a large amount of fluid when there is obvious breathing difficulties, and at this time chest pain can be slowed down.

3, systemic symptoms: depends on the cause of pleural effusion.

4, signs: a small amount of effusion may have pleural friction sound, the typical accumulation of fluid sign on the affected side of the thorax full, respiratory movements weakened, percussion dullness, tremor and respiratory sounds weakened or disappeared, the middle effusion in the upper edge of the percussion dull Sometimes bronchial breath sounds can be heard, and a large amount of effusion trachea shifts to the healthy side.

Examination of pleural effusion

1, routine inspection

(1) Appearance: The leakage liquid is often clear, transparent liquid, mostly pale yellow, standing and not solidified, the specific gravity is <1.016~1.018, the exudate can be different depending on the cause of the color, turbid, specific gravity>1.018, bloody The pleural effusion may be pale red blood due to hemorrhage (including red blood cells), water washing, macro blood (venous blood), tuberculous pleural effusion may have grass green, yellow or dark yellow, reddish, etc. The purulent effusion is yellow purulent, the anaerobic infection has a foul odor, and the amebic liver abscess breaks into the chest cavity, causing the effusion to be chocolate-colored. The diarrhea or P. aeruginosa infection is black and the pleural fluid is black and Green, chyle brood is milky white, self-coagulation.

(2) Cell counting and classification: the number of cells in the leakage is small, the number of nucleated cells is often less than 100×106/L, mainly lymphocytes and mesothelial cells, and the number of cells in the exudate is large, and there are nuclei. The number of cells is often more than 500 × 106 / L, mainly white blood cells, pneumonia and pleural effusion, the number of cells in the empyema can reach 10 × 109 / L or more, the number of red blood cells in the pleural effusion exceeds 5 × 109, pleural cavity The liquid can be light red, red blood cells 10×1010/L or more, and it is a gross blood pleural effusion, mainly found in trauma, tumor, pulmonary embolism, but it still needs to be differentiated from bloody pleural effusion caused by thoracic injury, pleural effusion. Neutrophils mainly include bacterial pneumonia, pancreatitis and other acute pleural inflammation; tuberculous pleurisy or tumor-induced pleural effusion is mainly lymphocytes; eosinophilia is mainly seen in parasitic infections. Fungal infection, spontaneous pneumothorax, tuberculous pleural effusion after repeated pumping, pulmonary infarction, chest trauma, etc., malignant pleural mesothelioma or malignant tumor involving the pleura, pleural effusion intermediate skin cells increased, often more than 5%, Non-neoplastic pleural effusion mesothelial cells <1%, Lupus cells can be found in pleural effusions in systemic lupus erythematosus with pleural effusion.

2, biochemical examination

(1) pH: tuberculous pleural effusion, pneumonia complicated with pleural effusion, rheumatoid pleural effusion, hemothorax, empyema pleural effusion pH <7.30, and in purulent pleural effusion, esophageal rupture Pleural effusion decreased more significantly, even pH <7.0, pH often >7.35 in SLE and malignant pleural effusion.

(2) Protein: Leakage protein content is low, <30g / L, mainly albumin, pleural effusion / blood protein content ratio <0.5, mucin test (Rivalta test) negative, high protein content in exudate , > 30g / L, pleural effusion / blood protein content ratio > 0.5, Rivalta test positive.

(3) Glucose: The glucose content in normal pleural effusion is similar to that of blood glucose. The glucose content in the leakage fluid is usually normal (>3.35mmol/L). The glucose in the pleural effusion caused by malignant tumor is also normal. The decrease of glucose content is mainly found in the class. Rheumatoid arthritis complicated with pleural effusion, tuberculous pleural effusion, suppurative pleural effusion, a few malignant pleural effusions, and purulent pleural effusion and rheumatoid arthritis complicated with pleural effusion glucose can be less than 1.10mmol / L.

(4) Lipid: The chylothorax pleural effusion contains more triglycerides (>1.2mmol/L), and its composition changes are related to the diet. It is mainly caused by tumor, parasitic or traumatic causes of thoracic catheter compression. Or rupture, spirulina Sudan III staining is red, and cholesterol content is normal, high cholesterol (>26mmol / L) in pseudo-chyle pleural effusion, mainly due to cholesterol accumulation, found in old tuberculous pleural effusion , rheumatoid arthritis pleural effusion, cancerous pleural effusion, cirrhosis, etc., usually triglyceride-negative, Sudan III staining negative.

3. Enzymatic determination

(1) adenosine deaminase (ADA): ADA is widely present in the tissue cells of the body, in which the content of lymphocytes and monocytes is high, with >45U/L as the elevation, tuberculous pleural effusion ADA is often obvious Elevated, up to 100U / L, infectious pleural effusion, such as pneumonia complicated by pleural effusion, suppurative pleural effusion and other ADA can also be increased, > 45U / L, tumor pleural effusion ADA usually decline (<45U /L, even <20U/L), ADA<45U/L can also be seen in rheumatoid arthritis pleural effusion, SLE complicated by pleural effusion.

(2) Lactate dehydrogenase (LDH): LDH content in pleural fluid, LDH/serum LDH ratio in pleural fluid is helpful to determine the nature of pleural effusion, LDH content in pleural fluid >200U/L, pleural fluid LDH/serum LDH The ratio of >0.6, can be diagnosed as exudate, and conversely considered leakage, LDH can be significantly increased in suppurative pleural effusion or malignant pleural effusion, up to 10 to 30 times the normal serum, including malignant pleural effusion The ratio of LDH to LDH in patients' serum is more than 35 times, and LDH isoenzyme LDH2 is increased, suggesting malignant pleural effusion, while LDH4 and LDH5 are mainly increased, which may be benign pleural effusion.

(3) Others: lung cancer (mainly small cell lung cancer) increased neutrophil enolase (NSE) in pleural fluid during pleural metastasis and pleural effusion, and angiotensin-converting enzyme (ACE) increased significantly in tuberculous pleural effusion (25u/L), lysozyme activity of tuberculous pleural effusion is often >80g/ml, while lytic activity of malignant pleural effusion is <65g/ml, the higher the lysozyme activity, the greater the possibility of tuberculous pleural effusion, prostate Cancer pleural metastasis with elevated pleural effusion acid phosphatase, acute pancreatitis, esophageal rupture, malignant tumor complicated with pleural effusion, pleural fluid amylase can be elevated, about 10% of patients with pancreatitis can be complicated by pleural effusion, pancreatic enzyme In particular, amylase overflows into pleural effusions, even above serum amylase levels.

4. Carcinoembryonic antigen (CEA) and serum sugar chain tumor-associated antigen

(CA50, CA125, CA19-9) CEA is a variety of tumor-associated markers, and CEA content in malignant pleural effusion is also increased, which can be used as a marker for differential diagnosis of malignant pleural effusion, CEA>1015g/L Or pleural fluid/serum CEA ratio >1, often suggestive of malignant pleural effusion, while CEA>20g/L, pleural fluid/serum CEA>1 diagnosis of malignant pleural effusion sensitivity and specificity are more than 90%, pleural fluid CEA For adenocarcinoma, especially gastrointestinal tumors secreting CEA in serum, lung adenocarcinoma, breast cancer caused by pleural effusion has a higher diagnostic value.

CA50 level in pleural effusion was higher than serum, CA50>20U/ml considered malignant pleural effusion, CA125, CA19-9 in pleural fluid increased in malignant pleural effusion, sensitivity was 100%, 36%, specificity 10% and 96% have a certain reference value for the diagnosis of malignant pleural effusion. The combined detection of CEA, CA50, CA125, CA19-9 for malignant pleural effusion is helpful to improve sensitivity and specificity.

5, immunological examination

Lymphocytes were found to be elevated in tuberculous and malignant pleural effusions. The former was mainly CD4-assisted lymphocytes (65%±), while the latter had lower CD4 cells and CD4/CD8 ratios than the former.

Neoplastic pleural effusion pleural fluid IL-1, IL-2, sIL-2R (soluble IL-2 receptor), IL-6, IL-8, PDGF (platelet-derived growth factor), IFN- (gamma interference) (TNF), TNF (tumor necrosis factor) often decreases, and is lower than tuberculous pleural effusion.

Bacterial pneumonia, tuberculosis, cancer, rheumatic fever with pleural effusion pleural fluid, rheumatoid factor titer is often increased, up to 1:160, systemic lupus erythematosus, rheumatoid arthritis pleural fluid complement component (CH50 , C3, C4) decreased, on the contrary, the content of immune complex in the pleural fluid increased, and the ratio of pleural fluid content/serum content was often greater than 1.

6, cytology examination

Malignant cells can be detected in about 40% to 80% of patients with malignant pleural effusion. Repeated examinations can improve the positive rate of detection. The initial positive rate is 40% to 60%, and can be increased by 80% for more than 3 times. Whether the tumor affects or invades the pleura, the type of tumor tissue, and the technical level of the diagnostic is closely related to the positive rate of detection. The chromosome number and morphological variation of the pleural fluid are mainly superdiploid and belong to aneuploidy. Abnormal chromosome structure, the possibility of malignant pleural effusion is large, using DNA flow cytometry immunohistochemistry to detect the DNA content of pleural fluid and important antigens of malignant tumor cells, for the diagnosis of malignant pleural effusion, and cells The combination of examination and examination can significantly improve the diagnostic sensitivity.

7, pathogen detection

Collect pleural effusion in a sterile test tube. Centrifuge the sediment. It is feasible to culture common bacteria, fungi, Mycobacterium tuberculosis, etc., and precipitate smear Gram stain or acid-fast stain to find common bacteria, fungi, Mycobacterium tuberculosis, tuberculosis The rapid diagnosis method of mycobacteria is detailed in the tuberculosis section. The pleural fluid sometimes needs to be cultured by anaerobic bacteria, and parasites (such as amoeba, paragonimiasis) are detected.

8, X-ray inspection

The pleural effusion can be a free effusion, or it can form a localized effusion due to adhesion. The distribution of free effusion is affected by the gravity of the effusion, the elastic retraction force of the lung tissue, the surface tension of the liquid and the negative pressure of the pleural cavity. Judging the amount of pleural effusion on the chest radiograph: The effusion is called a small amount of pleural effusion below the fourth anterior intercostal space, and the middle effusion between the 4th and 2nd front ribs, and the effusion is located between the 2nd front ribs. A large number of pleural effusions, a small amount of effusion, upright position, especially supine position X-ray examination is not easy to find, when the amount of fluid reaches 0.3 ~ 0.5L, only the rib angle becomes dull, sometimes difficult to identify with pleural thickening, often It is necessary to change the body position slowly by X-ray fluoroscopy, and as the effusion increases, the rib angle disappears, and the concave surface faces upward, and the outward, upward arc-shaped effusion shadow (Fig. 2), when a large amount of product appears In the case of fluid, the entire patient's chest cavity is densely shadowed, and the mediastinal trachea is pushed to the healthy side. The localized effusion can occur in any part of the chest cavity, usually divided into inter-leaf effusion, lung fundus, apical effusion, wall layer. Fluid and mediastinal fluid, it does not change with body position, smooth and full edge Mediastinal effusion sometimes leaves next ordinary X-ray examination is difficult to be differentiated from other diseases, B or CT examination often require further diagnosis.

9 , CT and MRI

CT has a special advantage in the diagnosis of pleural effusion. It is suitable for: 1 small amount of pleural effusion that is difficult to display by ordinary X-ray examination; 2 to distinguish the congenital effusion with other lesions by lesion density observation; 3 shows pleural cavity At the same time, it can understand the pressure of the lung tissue and the presence of lesions in the lungs. In the supine position, the effusion mainly concentrates on the back and extends to the lateral chest wall to form a slanted arc surface. MRI also has high resolution and can be detected. When a small amount of pleural effusion, non-hemorrhagic or cell and protein components are low, T1 is weighted to a low signal, otherwise it is a medium and high signal, the amount of fluid is independent of signal intensity, and T2 weighting of pleural effusion is a strong signal.

10, ultrasound examination

The pleural effusion can use A-type or B-type ultrasound system. At present, the real-time gray-scale B-mode ultrasonic diagnostic apparatus is used. The effusion is dark or anechoic in the B-ultrasound image, which is easy to distinguish, but the amount of fluid is very high. When the B-ultrasound image is not displayed well, it is difficult to identify and is less sensitive than CT. B-ultrasound guided pleural effusion can be used for the diagnosis and treatment of localized pleural effusion or adhesion-separated pleural effusion.

11, histological examination

Percutaneous pleural biopsy (referred to as pleural biopsy) for the diagnosis of tumor and tuberculous pleural effusion positive rate of about 30% to 70%, biopsy in most cases using blind detection method, pleural effusion may be unexplained, especially with The combination of chest and puncture can improve the positive rate of pleurisy diagnosis. If there is bleeding tendency, it should not be used when the amount of empyema or pleural fluid is very small.

Using the above-mentioned various examinations, there are still about 20% of patients with pleural effusion in the clinic. The cause of the pleural effusion is still unknown. Thoracoscopy or fiberoptic bronchoscopy can be used for thoracoscopy. The pleural cavity is observed under direct vision. The surface of the lung is observed, biopsy sampling, and traumaticity is relatively high. Small, easy to operate, safe, easy for patients to accept, high diagnostic positive rate, about 75% to 98%.

Diagnosis and differentiation of pleural effusion

diagnosis

1, chest tightness, chest pain, shortness of breath.

2. There is no positive sign when the amount of pleural effusion is small. When the amount of effusion is large, the respiratory movement of the affected side is weakened, the tremor disappears, the voiced sound or the sound is diagnosed, the breath sound is weakened or disappeared, and the trachea, mediastinum, and heart move to the healthy side.

3. When the amount of pleural effusion is 0.3-0.5L, the X-ray only sees the rib angle becoming dull; more effusion shows the effusion shadow on the outer side, the upward curved upper edge, and the effusion spreads when lying down. The whole lung field is reduced in brightness, and the liquid pleural effusion has a liquid level. When the effusion is large, the entire affected side is dark, and the mediastinum is pushed to the healthy side. The effusion often has a smooth and full edge, which is limited to between the leaves or between the lungs and the ankle. Ultrasound The examination is helpful for diagnosis.

4, B-ultrasound can detect the lumps covered by the pleural fluid, to assist in the positioning of the thoracic puncture, CT examination can be judged as exudate, blood or pus according to the different density of pleural fluid, can still show the mediastinum, paratracheal lymph nodes, lung Tumors and pleural mesothelioma and intrathoracic metastatic tumors, CT examination of pleural lesions have higher sensitivity and density resolution, easier to detect a small amount of effusion hard to show on X-ray film.

5, chest puncture to withdraw fluid, pleural effusion routine, biochemistry, immunology and cytology.

The above basis can be clearly identified as exudate or leakage, which is helpful for the diagnosis of the cause.

Differential diagnosis

Clinical need to be differentiated from rheumatic pleural effusion, cardiac pleural effusion, renal pleural effusion, pleural thickening, liquid pneumothorax, hepatic and pancreatic pleural effusion.

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