1. 6
PLEURAL EFFUSIONS

2. Aims of this subject: Define pleural effusion & discuss causes.
Transudate Vs Exudate for diagnosis.
Discuss the Important clinical clues that help in diagnosis.
Investigations.
Management.

3. ANATOMY OF THE PLEURA
The pleural space is bordered by parietal and visceral pleura.
Parietal pleurae cover the inner surface of the thoracic cavity, Visceral pleurae envelop all surfaces of the lungs.
Healthy individuals have less than 15 ml of fluid in each pleural space.

5. Definition Abnormal accumulation of fluid in the pleural space.
The principal function of pleural fluid is to provide a frictionless surface between the two pleurae in response to changes in lung volume with respiration.

6. Pathophysiology Normally, fluid enters the pleural space from the :
- Capillaries via parietal pleura.
- Interstitial spaces of lung via visceral pleura.
- Peritoneal cavity via holes in diaphragm
This fluid is normally removed by lymphatics in the visceral pleura, which have the capacity to absorb 20 times more fluid than is normally formed.

7. Mechanisms Altered permeability (e.g. inflammation)
Reduction in intravascular oncotic pressure (e.g. hypoalbuminemia)
Increased capillary hydrostatic pressure (e.g. congestive heart failure)
Reduction of pressure in pleural space; lung unable to expand (e.g. extensive atelectasis)
Decreased lymphatic drainage.

8. Mechanisms (2)
Increased fluid in peritoneal cavity, with migration across the diaphragm via the lymphatics (e.g. hepatic cirrhosis, peritoneal dialysis)
Movement of fluid from pulmonary edema across the visceral pleura.
Iatrogenic causes (e.g. central line misplacement)

9. History usually with Progressive dyspnea: Chest pain:
Most common presentation.
Indicates large effusion (usually not <500ml).
Chest pain:
Sharp or stabbing, with deep inspiration.
Pain may be localized to the chest wall or referred to the ipsilateral shoulder or upper abdomen possible malignant mesothelioma
intensity as the pleural effusion in size.

10. History (2) Non-productive cough
Pain is more suggestive of exudative effusion
Chest pain signifies pleural irritation, which can aid in the diagnosis of the cause of the effusion, since most transudative effusions do not cause direct pleural irritation.
Non-productive cough
Cough is usually related to the associated atelectasis, which to some degree accompanies all pleural effusions.

11. Physical Examination Inspection:
Asymmetric expansion of thoracic cage, with lagging expansion on the affected side (i.e., Hoover sign) .
May be bulging on affected side.

12. Physical Examination (2)
Palpation:
Chest expansion
Vocal fremitus
shifting of trachea to opposite side.
usually with large effusion >1000 ml

13. Physical Examination (3)
Percussion:
stony dullness
decreased tactile fremitus
Auscultation:
or absent breath sounds
vocal resonance
bronchial breathing & egophony above the fluid level
pleural friction rub

14. Thoracentesis and Pleural Fluid Analysis
To establish the etiology, a thoracentesis usually needs to be performed: 50 to 100 ml of fluid are usually removed and sent for analysis.
Not every effusion needs to be tapped, but when the patient has no obvious clinical cause for the effusion, is febrile, or has dyspnea, fluid should be removed.
The first step is to determine if the fluid is a transudate or an exudate.

15. Where to do???
Done through ICS over the area of maximum dullness on percussion or where the maximum opacity on x-ray is seen.
Usually 6th ICS laterally
or 8th ICS posteriorly.
After pleural ultrasound

16. Types Hydrothorax Hemothorax Chylothorax Pyothorax or Empyema
Hydro – serous fluid
Hemo – blood; pleural fluid hematocrit level of more than 50% of peripheral hematocrit level
Chylo – lipid; milkly fluid due to lymphatic obstruction or trauma to thoracic duct
Pyo – pus; purulent, putrid odor

17. Exudate VS transudate
An accurate diagnosis of the cause of the effusion, transudate versus exudate, relies on a comparison of the chemistries in the pleural fluid to those in the blood, using Light's criteria.
Most agree that exudates must meet one or more of the following criteria, whereas transudates meet none:
Pleural fluid/serum protein > 0.5 or
Fluid protein value > 3 g/dl.
Pleural fluid/serum LDH > 0.6 or
LDH value > 2/3 upper normal LDH serum limit
Pleural fluid cholesterol > 45 mg/dL

18. Transudate (1) Hepatic cirrhosis with and without ascites
Left ventricular failure
Nephrotic syndrome
Peritoneal dialysis/continuous ambulatory peritoneal dialysis
Hypoproteinemia (e.g., severe starvation)
Glomerulonephritis
Superior vena cava obstruction

19. Transudate (2) Congestive heart failure:
The criteria are less accurate for transudates caused by congestive heart failure, especially in patients who have undergone diuresis.
The longer diuretic therapy lasts, the more likely the fluid will have exudative characteristics, so examine the serum-to-pleural fluid albumin gradient (serum level minus pleural fluid level).
19 November 2018
Nephrology

20. Workup: Laboratory LDH > 1000 IU/L empyema, malignancy, rheumatoid
Glucose < 30 mg/dL
empyema, rheumatoid
Glucose between 30 – 50 mg/dL
lupus, malignancy, TB
pH highly correlates with glucose levels: pH < 7.30 associated with same list above for low glucose. For parapneumonic effusions, low pH more predictive of complicated effusions than low glucose.
Drain is pH <
Systemic antibiotics alone if pH > 7.3.
pH highly correlated with glucose levels: pH < 7.30 associated with same list above for low glucose. For parapneumonic effusions, low pH more predictive of complicated effusions than low glucose. Drain is pH < Systemic antibiotics alone if pH > 7.3.

21. Workup: Laboratory Lymphocytes > 85% Lymphocytes between 50 – 70%
Chylothorax, Lymphoma, Rheumatoid, TB
Lymphocytes between 50 – 70%
Malignancy
Mesothelial cells > 5%
TB unlikely
ADA > 43 U/mL
Supports TB

22. Exudate Exudative pleural effusion with: Bacterial pneumonia. TB
Pulmonary infarction.
uremia.
Hemorrhagic effusion.
Chylous effusion.
empyema.
Collagen vascular disease.
Malignant disorders.

23. Exudate (2)
Conditions causing pleural fluid with exudative or transudative characteristics:
Pulmonary embolism.
Hypothyroidism.
Pericardial disease (inflammatory or constrictive)
Atelectasis.
Sarcoidosis (usually an exudate)
Amyloidosis

24. Pleural Fluid Characteristics in Common Diseases
Comment
Glucose
RBC (per µl)
Total WBC
Appearance & predominant WBC
Etiology
Transudates
Usually bilateral
PF = S
0-1000
<1,000
Clear, straw-colored
Congestive heart failure
Incidence of 5% with ascites
<1000
500>
Cirrhosis
Exudates
Resolves with antibiotics only
<5000
5, ,000
Turbid
Parapneumonic (uncomplicated)
Requires drainage plus antibiotics
mg/dl
25, ,000
Turbid to purulent
Empyema
Small to moderate effusion with alveolar infiltrate & volume loss
Straw-colored to bloody
Pulmonary embolism
Cytology & pleural biopsy enable diagnosis in 80%
PF = S or<60 mg/dl
1000 to several hundred thousand
<10.000
Turbid to bloody
Malignancy
Positive TST, AFB smear and culture on pleural fluid or biopsy
1,000-5,000
Straw-colored to serosanguinous
Tuberculosis

25. Clinical Significance of Pleural Fluid Characteristics
Most likely an indication of malignancy in the absence of trauma; can also indicate pulmonary embolism, infection, pancreatitis, mesothelioma, or spontaneous pneumothorax
Bloody
Possible increased cellular content or lipid content
Turbid
Presence of chyle, cholesterol or empyema
Yellow or whitish, turbid
Rupture of amebic liver abscess into the pleural space
Brown (similar to chocolate sauce(
Aspergillus involvement of pleura
Black
Rheumatoid pleurisy
Yellow-green with debris
Malignant mesothelioma.
Highly viscous
Anaerobic infection of pleural space
Putrid odor

26. 19 November 2018

28. Workup: Imaging Upright Chest X-Ray Supine Chest X-Ray
Blunting of costophrenic angles
Supine Chest X-Ray
Increased density over lower lung fields
Lateral decubitus Chest X-Ray
Layering - indicates freely flowing and if 1cm thick indicates effusion > 200ml; failure to layer indicates loculation or another etiology.
Blunting of costophrenic angles with effusions > 175mL
Lateral: Layering indicates freely flowing and if 1cm thick indicates effusion > 200ml; Failure to layer indicates loculation or another etiology. Can detect as little as 5-10ml.

29. Decubitus effusion layered on downside effusion loculated in fissure
X-Rays
upright meniscus
Decubitus effusion layered on downside
effusion loculated in fissure

30. Is There a Difference?? Hint: look to the mediastinum
Total atelactasis:
mediastinum shifted toward whited out hemithorax
Massive pleural effusion:
mediastinum shifted away from whited out hemithorax

31. Workup: Imaging Pleural ultrasound Helps in:
identification of loculated effusions
differentiation of fluid from fibrosis
identification of thoracentesis site
Available at bedside

32. Workup: Imaging CT Scan Helps in differentiation of
Lung consolidation vs. Pleural effusion
Cystic vs. solid lesions
Peripheral lung abscess vs. loculated emypema
Helps in identification of
Necrotic areas
Pleural thickening, nodules, masses
Extent of tumor

33. Work up: Imaging

34. Pleural histology Proves the etiology of the pleural effusion
A pleural fragment can be obtained by:
needle pleural biopsy
thoracoscopy
thoracotomy

35. Management
It is usually directed to the treatment of the underlying cause.
Bed rest.
Therapeutics aspiration to relieve breathlessness, The recommended limit is about 1,000 ml at a single thoracentesis but removal of smaller volumes of ml usually alleviates severe symptoms. Aspiration of larger amount may cause pulmonary edema.

36. Management (2)
In cases of recurrent effusion such as in lung cancer, pleurodesis with tetracycline, bleomycin or talc can sclerose the pleural space and effectively prevent recurrence of the malignant pleural effusion.

37. Take a Message
Large pleural effusions, whether transudates or exudates, should be drained if they are causing severe respiratory symptoms, regardless of whether the cause is understood and disease-specific treatment is available. Relief of symptoms in these patients is the goal of drainage therapy.