Pleural effusion and empyema
Pleural effusion and empyema: Excerpt from Professional Guide to Diseases (Eighth Edition)
Pleural effusion is an excess of fluid in the pleural space. Normally, this space contains a small amount of extracellular fluid that lubricates the pleural surfaces. Increased production or inadequate removal of this fluid results in pleural effusion. Empyema is the accumulation of pus and necrotic tissue in the pleural space. Blood (hemothorax) and chyle (chylothorax) may also collect in this space.
Causes
The balance of osmotic and hydrostatic pressures in parietal pleural capillaries normally results in fluid movement into the pleural space. Balanced pressures in visceral pleural capillaries promote reabsorption of this fluid. Excessive hydrostatic pressure or decreased osmotic pressure can cause excessive amounts of fluid to pass across intact capillaries. The result is a transudative pleural effusion, an ultrafiltrate of plasma containing low concentrations of protein. Such effusions frequently result from heart failure, hepatic disease with ascites, peritoneal dialysis, hypoalbuminemia, and disorders resulting in overexpanded intravascular volume.
Exudative pleural effusions result when capillaries exhibit increased permeability with or without changes in hydrostatic and colloid osmotic pressures, allowing protein-rich fluid to leak into the pleural space. Exudative pleural effusions occur with tuberculosis (TB), subphrenic abscess, pancreatitis, bacterial or fungal pneumonitis or empyema, malignancy, pulmonary embolism with or without infarction, collagen disease (lupus erythematosus[LE]and rheumatoid arthritis), myxedema, and chest trauma.
Empyema is usually associated with infection in the pleural space. Such infection may be idiopathic or may be related to pneumonitis, carcinoma, perforation, or esophageal rupture.
Signs and symptoms
Patients with pleural effusion characteristically display symptoms relating to the underlying pathologic condition. Most patients with large effusions, particularly those with underlying pulmonary disease, complain of dyspnea. Those with effusions associated with pleurisy complain of pleuritic chest pain. Other clinical features depend on the cause of the effusion. Patients with empyema also develop fever and malaise.
Diagnosis
Auscultation of the chest reveals decreased breath sounds; percussion detects dullness over the effused area, which doesn’t change with breathing. Chest X-ray shows fluid in dependent regions. However, diagnosis also requires other tests to distinguish transudative from exudative effusions and to help pinpoint the underlying disorder.
The most useful test is thoracentesis, in which pleural fluid is analyzed in the laboratory to show components. Acute inflammatory white blood cells and microorganisms may be evident in empyema.
In addition, if a pleural effusion results from esophageal rupture or pancreatitis, fluid amylase levels are usually higher than serum levels. Aspirated fluid may be tested for LE cells, antinuclear antibodies, and neoplastic cells. It may also be analyzed for color and consistency; acid-fast bacillus, fungal, and bacterial cultures; and triglycerides (in chylothorax). Cell analysis shows leukocytosis in empyema. A negative tuberculin skin test strongly rules against TB as the cause. In exudative pleural effusions in which thoracentesis isn’t definitive, pleural biopsy may be done. This is particularly useful for confirming TB or malignancy.
Treatment
Depending on the amount of fluid present, symptomatic effusion may require thoracentesis to remove fluid or careful monitoring of the patient’s own reabsorption of the fluid. Hemothorax requires drainage to prevent fibrothorax formation. Pleural effusions associated with lung cancer commonly reaccumulate quickly. If a chest tube is inserted to drain the fluid, a sclerosing agent, such as talc, may be injected through the tube to cause adhesions between the parietal and visceral pleura, thereby obliterating the potential space for fluid to recollect.
Treatment of empyema requires insertion of one or more chest tubes after thoracentesis, to allow drainage of purulent material, and possibly decortication (surgical removal of the thick coating over the lung) or rib resection to allow open drainage and lung expansion. Empyema also requires parenteral antibiotics. Associated hypoxia requires oxygen administration.
Special considerations
❑ Explain thoracentesis to the patient. Before the procedure, tell him to expect a stinging sensation from the local anesthetic and a feeling of pressure when the needle is inserted. Instruct him to tell you immediately if he feels uncomfortable or has difficulty breathing during the procedure.
❑ Reassure the patient during thoracentesis. Remind him to breathe normally and avoid sudden movements, such as coughing or sighing. Monitor his vital signs, and watch for syncope. If fluid is removed too quickly, the patient may suffer bradycardia, hypotension, pain, pulmonary edema, or even cardiac arrest. Watch for respiratory distress or pneumothorax (sudden onset of dyspnea and cyanosis) after thoracentesis.
❑ Administer oxygen and, in empyema, antibiotics, as ordered.
❑ Encourage the patient to perform deep-breathing exercises to promote lung expansion. Use an incentive spirometer to promote deep breathing.
❑ Provide meticulous chest tube care, and use sterile technique for changing dressings around the tube insertion site in empyema. Ensure tube patency by watching for fluctuations of fluid or air bubbling in the underwater seal chamber. Continuous bubbling may indicate an air leak. Record the amount, color, and consistency of any tube drainage.
❑ If the patient has open drainage through a rib resection or intercostal tube, use hand and dressing precautions. Because weeks of such drainage are usually necessary to obliterate the space, make visiting nurse referrals for the patient who will be discharged with the tube in place.
❑ If pleural effusion was a complication of pneumonia or influenza, advise prompt medical attention for upper respiratory infections.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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