raed abu sham’a, m

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