raed abu sham’a, m
TRANSCRIPT
Raed Abu Sham’a, M.D
Mechanisms leading to accumulation of fluid in
pleural spaces are:
Increased hydrostatic pressure eg CHF.
Increased capillary permeability eg malignancy
Direct extravasation eg Chylothorax
Negative pressure induced eg trapped lung
PATHOPHYSIOLOGY
Dyspnea from pleural effusions is related more
to distortion of the diaphragm and chest wall during respiration than to hypoxemia.
Dyspnea also can be caused by:
underlying intrinsic lung or heart disease
obstructing endobronchial lesions
diaphragmatic paralysis
History
Less common symptoms include:
Mild, nonproductive cough
Chest pain.
More severe cough or production of purulent or bloody sputum suggests an underlying pneumonia or endobronchial lesion.
Constant chest wall pain might reflect chest wall invasion by carcinoma or mesothelioma.
Pleuritic chest pain suggests either pulmonary embolism or an inflammatory pleural process.
Systemic toxicity evidenced by fever, weight loss, and inanition suggests empyema
Physical findings do not usually manifest until
pleural effusions exceed 300 mL
Decreased breath sounds Dullness to percussion Decreased tactile fremitus Egophony ("E" to "A" change) Pleural friction rub Mediastinal shift away from the effusion
(observed with effusions >1000 mL)
Physical Examination
Transudates are ultrafiltrates of plasma in the
pleura, include the following: Congestive heart failure Liver Cirrhosis Nephrotic syndrome Atelectasis Peritoneal dialysis Myxedema Constrictive pericarditis
Causes
Exudates include the following:
Parapneumonic Malignancy Tuberculosis Pulmonary embolism Collagen-vascular Asbestosis Trauma Postcardiac injury
syndrome
Pancreatitis Esophageal
perforation Radiation pleuritis Drug-induced Chylothorax Meig’s syndrome Sarcoidosis Yellow nail syndrome
It deffrentiates pleural fluid transudates from exudates
Frankly purulent fluid indicates an empyema.
Grossly bloody fluid with hematocrit level of more than 50% of the peripheral hematocrit level defines a hemothorax.
A milky, opalescent fluid suggests a chylothorax, resulting most often from:
lymphatic obstruction by malignancy
thoracic duct injury by trauma or surgery
Laboratory Studies
Pleural fluid - Serum protein ratio more
than 0.5
Pleural fluid - Serum LDH ratio more than 0.6
Pleural fluid LDH more than two thirds of normal serum value
Light’s Criteria
Pleural fluid measurement alone might have comparable sensitivity and specificity to Light's criteria
Pleural fluid LDH more than 0.45 of upper limit of normal serum values
Pleural fluid cholesterol more than 45 mg/dL
Pleural fluid protein more than 2.9 g/dL
In parapneumonic effusions:
pH < 7.1-7.2 indicates the need for urgent drainage
pH > 7.3 suggests that the effusion can be managed coservatively.
In malignant effusions, pleural fluid pH < 7.3 is associated with:
extensive pleural involvement
higher yield on cytology
decreased success of pleurodesis
shorter survival times.
Pleural Fluid pH
If an exudate is clinically suggestive or is confirmed by
chemistry tests, send pleural fluid for:
Total cell counts and differential
Gram stain and culture
Cytology.
Suspect malignant effusions in patients with known
cancer or with lymphocytic, exudative effusions, especially when bloody.
Pleural Fluid
Tumor involvement of the pleura is diagnosed most easily by
pleural fluid cytology.
Cytological examination of a single pleural fluid specimen has
a diagnostic yield of 54-63% for malignancy and increases to
77% when 3 serial specimens are obtained.
Closed-needle pleural biopsy is a bedside procedure that can
increase the yield for malignancy by an additional 7%.
Tumor markers, such as carcinoembryonic antigen, are
suggestive of malignant effusions when pleural fluid values
are very high.
Suspect tuberculosis (TB) pleuritis in patients with:
history of exposure
positive PPD test
patients with exudative effusions that are predominantly
lymphocytic
Most tuberculous pleural effusions probably result from a
hypersensitivity reaction to the mycobacterium not from
microbial invasion of the pleura
AFB stains of pleural fluid rarely are diagnostic (<10% of
cases)
Pleural fluid cultures grow Mycobacterium tuberculosis
in less than 65% of cases.
Histology and culture of pleural tissue obtained by
closed-needle pleural biopsy increase the diagnostic
yield to 80-90%.
Adenosine deaminase (ADA) activity of more than 43
U/mL in pleural fluid supports the diagnosis of TB
pleuritis.
Pleural ADA values less than 43 U/mL do not
exclude the diagnosis of TB pleuritis.
Measure pleural fluid amylase if a pancreatic origin
or ruptured esophagus is suspected or if a unilateral left pleural effusion remains undiagnosed after initial testing.
Measure triglycerides on milky pleural fluids when chylothorax is suspected.
Consider immunologic studies, including pleural fluid ANA and RF, when collagen vascular diseases are suspected.
Additional Specialized Tests
25% of exudative effusions remain undiagnosed.
Among patients with undiagnosed pleural effusions after primary evaluation, predict a benign course for those who meet all 6 of the following clinical parameters
1. Clinical stability
2. Absence of weight loss
3. Negative PPD result and pleural ADA less than 43 U/mL
4. Absence of fever
5. Pleural fluid differential cell count with less than 95%
lymphocytes
6. Effusion that occupies less than 50% of the hemithorax
Imaging Studies
Chest radiograph
Effusions of more than 150-200 mL usually are apparent as blunting of the costophrenic angle on PA chest X-ray.
Chest Radiograph
Moderate-to-large pleural effusions might appear as a homogenous density over the lung fields.
Lateral Chest Films
Chest Radiograph
Subpulmonic Effusions
Apparent elevation of the hemidiaphragm, lateral displacement of the dome of the diaphragm, or increased distance between the apparent left hemidiaphragm and the gastric air bubble suggest subpulmonic effusions.
They more reliably detect smaller pleural
effusions.
Layering of an effusion on lateral decubitus films defines a freely flowing effusion and, if the layering fluid is 1 cm thick, indicates an effusion amenable to thoracentesis.
Failure of an effusion to layer on lateral decubitus films indicates loculated pleural fluid.
Lateral Decubitus Films
Lateral Decubitus
Film
Lateral Decubitus Film
Chest Radiograph
Chest radiographs can reveal other diagnostic clues to the cause of an effusion.
Large unilateral effusions typically shift the mediastinum to the contralateral hemithorax.
Lack of mediastinal shift with an apparent large effusion suggests: Bronchial obstruction
Infiltration of the lung with tumor or inflammatory cells
Mesothelioma
Fixed mediastinum from tumor or fibrosis.
Chest Radiograph
Lack of mediastinal shift with an apparent large effusion
Air-fluid levels in the pleural space suggest:
Bronchopleural fistula
Pneumothorax
Gas-forming organisms
Esophageal rupture
Congestive Heart Failure
Bilateral effusions
Enlarged heart shadows
Malignancy
Left Pleural Effusion
Lt. Mediastenal Mass
Asbestosis
Pleural plaques and calcifications usually indicate previous asbestos exposure
Ultrasound serves to identify the safest site for
performing thoracentesis or pleural biopsy. CT scanning provides detailed information
about pleural and parenchymal lesions. Spiral CT angiography may be useful if
pulmonary embolism is suspected as the cause for the effusion.
CT scanning also can identify multiple loculations, and direct small drainage catheters into loculated pleural collections.
Imaging Studies
Perform diagnostic thoracentesis if the etiology of the
effusion is unclear or if the patient is not clinically stable.
Pleural effusions do not require thoracentesis:
If too small to safely aspirate
Clinically stable patients, if explained
Relative contraindications to thoracentesis:
Small volume of fluid
Bleeding diathesis or systemic anticoagulation
Mechanical ventilation
Cutaneous disease over the puncture site.
Thoracentesis
Complications of diagnostic thoracentesis:
Pain at the puncture site
Cutaneous or internal bleeding
Pneumothorax in 12% of cases
Empyema
Spleen/liver puncture
Chronic obstructive or fibrotic lung disease increases the risk of symptomatic pneumothorax
Thoracentesis
Removal of larger amounts of pleural fluid to
alleviate dyspnea and to prevent ongoing
inflammation and fibrosis.
Only remove moderate amounts of pleural fluid to
avoid reexpansion of pulmonary edema and to
avoid causing a pneumothorax.
The recommended limit is 1000-1500 mL in a single
thoracentesis procedure.
Therapeutic Thoracentesis
Most complicated parapneumonic effusions and empyemas
require drainage by tube thoracostomy.
Traditionally, large-bore chest tubes (20-36F) have been used
to drain thick pleural fluid and to break up loculations in
empyemas.
Insertion of additional pleural catheters, usually under
radiographic guidance, or instilling fibrinolytics (eg,
streptokinase, urokinase) through the pleural catheter can
drain multiloculated pleural effusions.
Tube Thoracostomy
Tube Thoracostomy
Pleurodesis or pleural sclerosis is used most often for
recurrent malignant effusions.
The goal of therapy is to palliate symptoms while minimizing patient discomfort and the duration of hospitalization and overall costs.
Pleural fluid pH might provide a useful guide to the overall life expectancy of patients with recurrent malignant effusions.
Pleurodesis or Pleural Sclerosis
Various agents, including talc, quinacrine hydrochloride,
bleomycin sulfate (Blenoxane), and doxycycline, can sclerose
the pleural space and effectively prevent recurrence of the
malignant pleural effusion.
They can be administered through chest tubes or pleural
catheters.
All sclerosing agents can produce fever, chest pain, and
nausea.
Pleurodesis or Pleural Sclerosis
Transudative effusions usually are managed by
treating the underlying medical disorder.
Drain large pleural effusions if they are causing severe respiratory symptoms.
The management of exudative effusions depends on the underlying etiology of the effusion.
Drain complicated parapneumonic effusions and empyemas to avoid fibrosing pleuritis.
TREATMENT
Frankly purulent fluid
Pleural fluid ph less than 7.2
Loculated effusions
Bacteria on gram stain or culture.
Radiographically reassess patients with parapneumonic effusions who do not improve or deteriorate clinically.
Indications for urgent drainage of parapneumonic effusions
Decortication usually is needed to remove a thick,
inelastic pleural peel that restricts ventilation and
produces progressive or refractory dyspnea.
Surgically implanted pleuroperitoneal shunts are
another treatment option for recurrent symptomatic
effusions.
Surgical Treatment
Thoracoscopy
Prognosis varies in accordance with underlying
etiology.
Malignant effusions convey a very poor prognosis, typically measured in months.
Parapneumonic effusions, when recognized and treated promptly, typically resolve without significant sequelae.
Untreated or inappropriately treated parapneumonic effusions might lead to constrictive fibrosis.
Prognosis
Dr. Raed Abu Sham’a