Basics
Description
Accumulation of fluid in the pleural cavity
Pathophysiology
- Normally 1 " 15 mL of fluid in the pleural space
- Alterations in the flow and/or absorption of this fluid lead to its accumulation.
- Mechanisms that influence this flow of fluid:
- Increased capillary hydrostatic pressure (i.e., congestive heart failure [CHF], overhydration)
- Decreased pleural space hydrostatic pressure (i.e., after thoracentesis, atelectasis)
- Decreased plasma oncotic pressure (i.e., hypoalbuminemia, nephrosis)
- Increased capillary permeability (i.e., infection, toxins, connective tissue diseases, malignancy)
- Impaired lymphatic drainage from the pleural space (i.e., disruption of the thoracic duct)
- Passage of fluid from the peritoneal cavity through the diaphragm to the pleural space (i.e., hepatic cirrhosis with ascites)
- 2 types of pleural effusion:
- Transudate: Mechanical forces of hydrostatic and oncotic pressures are altered, favoring liquid filtration.
- Exudate: Damage to the pleural surface occurs that alters its ability to filter pleural fluid; lymphatic drainage is diminished.
- Stages associated with parapneumonic effusions (infectious exudates):
- See Appendix, Table 3.
- Exudative stage
- Free-flowing fluid
- Pleural fluid glucose, protein, lactate dehydrogenase (LDH) level, and pH are normal.
- Fibrinolytic stage
- Loculations are forming.
- Increase in fibrin, polymorphonuclear leukocytes, and bacterial invasion of pleural cavity are occurring.
- Pleural fluid glucose and pH falls while protein and LDH levels increase.
- Organizing stage (empyema)
- Fibroblasts grow.
- Pleural peal forms.
- Pleural fluid parameters worsen.
Diagnosis
History
- Underlying disease determines most systemic symptoms.
- Patient may be asymptomatic until the amount of fluid is large enough to cause cardiorespiratory compromise/distress.
- Dyspnea and cough are associated with large effusions.
- Fever (if infectious etiology)
- Pleuritic pain (pneumonia may cause irritation of the parietal pleura, causing pleural pain; as the effusion increases and separates the pleural membrane, the pain may disappear)
Physical Exam
- Decreased thoracic wall excursion on the ipsilateral side
- Fullness of intercostal spaces on the ipsilateral side
- Trachea and cardiac apex displaced toward the contralateral side (may produce a mediastinal shift that can reduce venous return and compromise the cardiac output)
- Dull or flat percussion on the ipsilateral side (suggesting the presence of consolidation of pleural effusion)
- Decreased tactile and vocal fremitus
- Decreased whispering pectoriloquy
- Pleural rub during early phase (may resolve as fluid accumulates in the pleural space)
- Decreased breath sounds
Diagnostic Tests & Interpretation
- Cytologic exam of pleural fluid
- Fresh and heparinized specimen should be refrigerated at 4 °C (39.2 °F) until it can be processed.
- Fixatives should not be added.
- Pleural fluid parameters to be routinely measured include the following (Appendix, Table 4):
- pH
- LDH
- Protein
- Glucose
- Note: Glucose of <40 mg/dL suggests a para-pneumonic, tuberculosis, malignant, or rheumatic etiology to the effusion.
Lab
Initial lab tests
Serology values to follow the degree of inflammation and the response to therapy:
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
Imaging
- Chest radiograph
- Anteroposterior projection can show >400 mL of pleural fluid.
- Lateral projection can show <200 mL of pleural fluid.
- Lateral decubitus film to evaluate for free-flowing pleural fluid can show as little as 50 mL of pleural fluid.
- Ultrasound
- Reveals small (3 " 5 mL) loculated collections of pleural fluid
- Useful as a guide for thoracentesis
- Aids in distinguishing between pleural thickening and pleural effusion
- CT scan
- Clearly reveals effusions/empyemas, abscess, or pulmonary consolidations
- Useful for defining the extent of loculated effusions
Diagnostic Procedures/Other
- Thoracentesis
- Indicated whenever etiology is unclear or if the effusion causes symptoms (e.g., prolonged fever or respiratory distress)
- Pleural biopsy
- If thoracentesis is nondiagnostic
- Most useful for diseases that cause extensive involvement of the pleura (i.e., tuberculosis, malignancies)
- Confirms neoplastic involvement in 40 " 70% of cases
Differential Diagnosis
- Transudate
- Cardiovascular
- CHF
- Constrictive pericarditis
- Nephrotic syndrome with hypoalbuminemia
- Cirrhosis
- Atelectasis
- Exudate
- Infection
- Staphylococcus aureus (increasing incidence of methicillin-resistant species)
- Streptococcus pneumoniae (increasing incidence of penicillin-resistant species)
- Haemophilus influenzae (decreasing incidence since introduction of H. influenzae type b [Hib] vaccine)
- Group A Streptococcus
- Anaerobes
- Gram-negative enterics
- No identified organisms (all cultures sterile)
- Tuberculous effusion
- Viral effusions (adenovirus, influenza)
- Fungal effusions: most not associated with effusions; Nocardia and Actinomyces are most commonly seen.
- Parasitic effusions
- Neoplasm: seen mostly in leukemia and lymphoma; uncommon in children
- Connective tissue disease
- Rheumatoid arthritis
- Systemic lupus erythematosus
- Wegener granulomatosis
- Pulmonary embolus
- Intra-abdominal disease
- Subdiaphragmatic abscess
- Pancreatitis
- Sarcoidosis
- Esophageal rupture
- Hemothorax
- Chylothorax
- Drugs
- Chemical injury
- Postirradiation effusion
Treatment
Medication
- Antibiotics
- Used when effusion is caused by a bacterial infection
- Specific antibiotics dictated by organism identified
- If effusion is sterile, broad-spectrum antibiotics are indicated to cover for the usually seen organisms.
- Clinical improvement usually begins within 48 " 72 hours of therapy.
- Continue IV antibiotics until afebrile.
- Complete remainder of therapy on oral antibiotics.
- Duration of antibiotic therapy depends on the infectious organism and the degree of illness:
- Total duration is controversial.
- Usually, at least 2 " 4 weeks of total IV and PO
Additional Treatment
General Measures
- Supportive measures:
- Maintain adequate
- Oxygenation
- Fluid status
- Nutritional balance
- Antipyretic agents when febrile
- Pain control
- Treat the underlying disease:
- Antibiotics for infections
- Cardiac medications for CHF
- Chemotherapeutic agents for malignancies
- Anti-inflammatory agents (i.e., steroids) for connective tissue diseases
- Medium-chain triglycerides and low-fat diet for chylothorax
- Effective drainage of pleural fluid
- Thoracentesis
- Chest tube drainage
- Surgical drainage
- Duration of chest tube drainage
- Discontinue when patient is asymptomatic (afebrile, no distress) and drainage <50 mL/h
- Thick, loculated empyema requires prolonged drainage (and possibly a video-assisted thoracic surgery [VATS] procedure if effusion not improving).
Complementary & Alternative Therapies
- Thoracentesis
- For diagnosis purposes
- To distinguish between a transudate and an exudate
- For culture material (if infection is suspected)
- For cytology (if malignancy is suspected)
- For relief of dyspnea or cardiorespiratory distress
- Chest tube thoracostomy
- Reduce reaccumulation of fluid.
- Drain parapneumonic effusion (before loculations develop which will prevent fluid drainage).
- Intrapleural fibrinolytics
- Adjunct to aid in drainage of complicated (i.e., multiloculated empyema) pleural effusions
- Streptokinase, urokinase, and tPA are the agents of choice.
Surgery/Other Procedures
- VATS
- Alternative to more invasive procedures (e.g., open thoracotomy/decortication)
- Debridement through pleural visualization and lysis of adhesions/loculations
- Useful when
- Initial drainage is delayed
- Loculations prevent adequate drainage by chest tube alone
- Patient is failing more conservative therapy
- Pleurectomy
- Chylothorax
- Malignant effusions
- Pleurodesis
- For recurrent effusions
- Chemical agents frequently used include talc, tetracycline, doxycycline, and quinacrine.
- Surgical methods include the following:
- Mechanical abrasion
- Pleurectomy via VATS
- Open thoracotomy route
- In cases of malignant effusion:
- Sclerosing procedures are usually ineffective.
- Chest tube drainage can create a pneumothorax because the lung is incarcerated by the tumor.
Ongoing Care
Follow-up Recommendations
- Clinical improvement usually within 1 " 2 weeks
- With empyemas, the patient may have fever spikes for up to 2 " 3 weeks after improvement is noted.
Diet
When the effusion is a chylothorax:
- Medium-chain triglycerides
- Nutritional replacement
- At least 4 " 5 weeks on this regimen
Prognosis
Depends on underlying disease process:
- Properly treated infectious cause: excellent prognosis
- Malignancy: poor prognosis
Complications
- Hypoxia
- Respiratory distress
- Persistent fevers
- Decreased cardiac function
- Malnutrition (seen in chylothorax)
- Shock (secondary to blood loss in cases of hemothorax)
- Trapped lung
Additional Reading
- Beers SL, Abramo TJ. Pleural effusions. Pediatr Emerg Care. 2007;23(5):330 " 334. [View Abstract]
- Buckingham SC, King MD, Miller ML. Incidence and etiologies of complicated parapneumonic effusions in children. Pediatr Infect Dis. 2003;22(6):499 " 504. [View Abstract]
- Calder A, Owens CM. Imaging of parapneumonic pleural effusions and empyema in children. Pediatr Radiol. 2009;39(6):527 " 537. [View Abstract]
- Doski JJ, Lou D, Hicks BA, et al. Management of parapneumonic collections in infants and children. J Pediatr Surg. 2000;35(2):265 " 268; discussion 269 " 270. [View Abstract]
- Heffner JE. Discriminating between transudates and exudates. Clin Chest Med. 2006;27(2):241 " 252. [View Abstract]
- Krenke K, Peradzynska J, Lange J. Local treatment of empyema in children: a systematic review of randomized controlled trials. Acta Paediatr. 2010;99(10):1449 " 1453. [View Abstract]
- Merino JM, CarpinteroI I, Alvarez T, et al. Tuberculous pleural effusion in children. Chest. 1999;115(1):26 " 30. [View Abstract]
- Proesmans M, De Boeck K. Clinical Practice: Treatment of childhood empyema. Eur J Pediatr. 2009;168(6):639 " 645. [View Abstract]
- Rocha G. Pleural effusions in the neonate. Curr Opin Pulm Med. 2007;13(4):305 " 311. [View Abstract]
Codes
ICD09
- 511.9 Unspecified pleural effusion
- 510.9 Empyema without mention of fistula
- 511.81 Malignant pleural effusion
- 012.00 Tuberculous pleurisy, unspecified
- 511.89 Other specified forms of effusion, except tuberculous
ICD10
- J90 Pleural effusion, not elsewhere classified
- J86.9 Pyothorax without fistula
- J91.0 Malignant pleural effusion
- A15.6 Tuberculous pleurisy
- J91.8 Pleural effusion in other conditions classified elsewhere
SNOMED
- 60046008 Pleural effusion (disorder)
- 58554001 Empyema of pleura
- 83270006 Neoplastic pleural effusion (disorder)
- 446986002 Tuberculous pleural effusion (disorder)
FAQ
- Q: When will the chest radiograph findings become normal?
- A: They may take up to 6 months (or longer) to return to normal appearance.
- Q: When will the pulmonary function tests normalize?
- A: Depending on extent of effusion, they may take up to 6 " 12 months.