Pleural Effusion

Question 1

Form when there is ↑ capillary hydrostatic pressure or ↓ osmotic pressure

occurs when SYSTEMIC FACTORS that influence the formation and absorption of pleural fluid are altered

Answer 1

TRANSUDATES

CAUSES
• CHF (left heart failure) – MC cause
• hypoalbuminemia
• cirrhosis
• nephrotic syndrome

Question 2

Result of inflammation

occurs when LOCAL FACTORS that influence the formation and absorption of pleural fluid are altered

Answer 2

EXUDATES

CAUSES
parapneumonic effusion - MCC
malignancy – 2nd MC cause
empyema – exudate w/ pus
hemothorax – fluid that has a hematocrit that is >50% of the blood hematocrit
chylothorax – w/ ↑ triglycerides or cholesterol

Question 3

Diseases that usually produce BILATERAL EFFUSIONS

Answer 3

Congestive heart failure

If there are markedly different amounts in each hemithorax, suspect a parapneumonic effusion or malignancy on the side with the greater volume of fluid

lupus erythematosus usually produces bilateral effusions, but when UNILATERAL - LEFT-SIDED

Question 4

Diseases that can produce effusions on EITHER SIDE (but usually unilateral)

Answer 4

• tuberculosis and other exudative effusions associated with infectious agents, including viruses
• pulmonary thromboembolic disease
• trauma

Question 5

Diseases that usually produce LEFT-SIDED EFFUSIONS

Answer 5

• pancreatitis
• distal thoracic duct obstruction
• Dressler syndrome

Question 6

Diseases that usually produce RIGHT-SIDED EFFUSIONS

Answer 6

• abdominal disease related to the liver or ovaries (some ovarian tumors can be associated with a right pleural effusion and ascites [MEIGS SYNDROME]
• rheumatoid arthritis - can produce an effusion that remains unchanged for years
• proximal thoracic duct obstruction

Question 7

Light’s Criteria

Answer 7

1. pleural fluid protein/serum protein >0.5
2. pleural fluid LDH/serum LDH >0.6
3. pleural fluid LDH > 2/3 the normal upper limit for serum

Question 8

Light’s Criteria

Answer 8

EXUDATIVE pleural effusions MEET AT LEAST ONE of the following criteria, whereas transudative pleural effusions meet none:

1. pleural fluid protein/serum protein >0.5
2. pleural fluid LDH/serum LDH >0.6
3. pleural fluid LDH > 2/3 the normal upper limit for serum

if one or more of the exudative criteria are met and the patient is clinically thought to have a condition producing a transudative effusion, the difference between the protein levels in the serum and the pleural fluid should be measured

if this gradient is >31 g/L (3.1 g/dL), the exudative categorization by these criteria can be ignored because almost all such patients have a TRANSUDATIVE pleural effusion

Question 9

IF A PATIENT HAS AN EXUDATIVE PLEURAL EFFUSION, THE FOLLOWING TESTS ON THE PLEURAL FLUID SHOULD BE OBTAINED:

Answer 9

description of the appearance of the fluid
glucose level
differential cell count
microbiologic studies
cytology

Question 10

The MC cause of pleural effusion

Answer 10

left ventricular failure

Question 11

Diagnostic that the effusion is secondary to congestive heart failure

Answer 11

pleural fluid N-terminal pro-brain natriuretic peptide
(NT-proBNP) >1500 pg/mL

Question 12

pleural effusions occur in ~5% of patients with cirrhosis and ascites

Answer 12

Hepatic Hydrothorax

direct movement of peritoneal fluid through small openings in the diaphragm into the pleural space – predominant mechanism

effusion is usually right-sided

frequently is large enough to produce severe dyspnea

Question 13

Associated with BACTERIAL pneumonia, LUNG ABSCESS, or BRONCHIECTASIS

the MC cause of exudative pleural effusion (US)

Answer 13

Parapneumonic Effusion

Question 14

FACTORS INDICATING THE LIKELY NEED FOR A PROCEDURE MORE INVASIVE THAN A THORACENTESIS (in increasing order of importance)

Answer 14

• loculated pleural fluid
• pleural fluid pH <7.20
• pleural fluid glucose <3.3 mmol/l (<60 mg/dl)
• positive Gram stain or culture of the pleural fluid
• presence of gross pus in the pleural space

Question 15

the 2nd MC type of exudative pleural effusion

Answer 15

Effusion Secondary to Malignancy

Question 16

3 TUMORS THAT CAUSE ~75% OF ALL MALIGNANT PLEURAL EFFUSIONS

Answer 16

lung carcinoma
breast carcinoma
lymphoma

Question 17

Primary tumors that arise from the mesothelial cells that line the pleural cavities; most are related to asbestos exposure

Answer 17

mesothelioma

Question 18

disrupted thoracic duct –> chyle accumulates in the pleural space

trauma (i.e. thoracic surgery) – MC cause

may result from tumors in the mediastinum

Answer 18

Chylothorax

Question 19

MCC of pleural effusion

Answer 19

Left Ventricular Failure

Question 20

MCC of exudative pleural effusion (US)

Answer 20

Parapneumonic effusion

Question 21

2nd MCC of exudative pleural effusion

Answer 21

Malignancy

Question 22

3 tumors causing 75% of all malignant pleural effusions

Answer 22

Lung carcinoma
Breast carcinoma
Lymphoma

Question 23

MCC of exudative pleural effusion in many parts of the world

Answer 23

TB

Question 24

MC overlooked cause of undiagnosed pleural effusion

Answer 24

Pulmonary Embolism

Question 25

MCC of chylothorax

Answer 25

Trauma