Disorders of the plueral

Question 1

Abnormal accumulation of fluid in the pleural space, which is the potential space between the visceral and parietal pleura surrounding the lungs.

Answer 1

Pleural effusions

Question 2

Causes of fluid accumulation

Answer 2

➢ Primary (primary intra-pleural bacterial infections,
primary neoplasm of the pleura)
➢ Secondary pleural diseases (secondary complication of some underlying disease)

Question 3

Aetiology of plueral effusions

Answer 3

➢ Increased hydrostatic pressure in visceral pleura (e.g.Congestive Heart Failure)
➢ Decreased oncotic pressure (e.g. Nephrotic Syndrome)
➢ Increased vessel permeability of visceral pleura
capillaries (Pulmonary infarction, Pneumonia)
➢ Increased intra-pleural negative pressure (e.g.
Atelectasis)
➢ Decreased lymphatic drainage (e.g. mediastinal
Carcinomatosis)

Question 4

Types of Pleural Effusions

Answer 4

Transudates & Exudates

Question 5

What causes transudative pleural effusions?

Answer 5

Transudates are caused by disturbances in Starling pressures, such as:
Increased hydrostatic pressure: e.g., Congestive Heart Failure
Decreased oncotic pressure: e.g., Nephrotic Syndrome

Question 6

What is the composition of transudative pleural effusions?

Answer 6

Transudates are an ultra-filtrate of plasma, with low protein & low cellular content.

Question 7

What causes exudative pleural effusions?

Answer 7

Exudates are caused by increased vascular permeability due to acute inflammation.

Question 8

What is the composition of exudative pleural effusions?

Answer 8

Exudates are protein-rich and cell-rich fluid.

Question 9

What are some examples of conditions causing exudative pleural effusions?

Answer 9

Pneumonia
Tuberculosis
Pulmonary infarction
Malignancy/metastas

Question 10

Clinical findings of plueral effusions

Answer 10

➢ Dullness to percussion
➢ Absent breath sounds
➢ Absent vocal tactile fremitus
➢ Contralateral shift of the mediastinum

Question 11

Imaging studies of plueral effusions

Answer 11

➢ Blunting of the costo-phrenic angle
➢ Obscuration of the diaphragm

Question 12

Non-inflammatory collection of serous fluid
within the pleural cavities

Answer 12

Hydrothorax

Question 13

Causes of hyrdothorax

Answer 13

➢ Cardiac failure (Hydrothorax accompanied by
pulmonary congestion and oedema)
➢ Systemic diseases associated with generalised
oedema (e.g. Renal Failure, Cirrhosis of the liver)

Question 14

Microscopic pic of hydroothorax

Answer 14

Clear & straw coloured fluid

Question 15

Cause of Haemothorax

Answer 15

Complication of a ruptured aortic aneurysm
or vascular trauma or post-operative occurrence

Question 15

Escape of blood into the pleural cavity

Answer 15

Haemothorax

Question 16

Macroscopic features of Haemothorax

Answer 16

Large clots of blood within the pleural spaces

Question 17

Cause of Pseudo-Chylothorax

Answer 17

Rheumatoid arthritis, other collagen vascular diseases, Tbc.

Question 18

What are the macroscopic features of pseudochylothorax?

Answer 18

Cloudy, opalescent (sparkling) fluid

Question 19

What is the lipid profile in pseudochylothorax?

Answer 19

Rich in cholesterol
Normal triglyceride levels
No chylomicrons

Question 20

What type of cells may be present in pseudochylothorax?

Answer 20

Lipid-laden macrophages.

Question 21

Chronic pleural effusion linked to inflammation, results in the

Answer 21

Breakdown of necrotic debris & accumulation of cholesterol

Question 22

Rare condition that results from thoracic
duct damage, with chyle leakage from the lymphatic
system into the pleural space

Answer 22

chylothorax

Question 23

What is empyema?

Answer 23

A purulent pleural exudate caused by bacterial or fungal seeding of the pleural space.

Question 24

What are the causes of empyema?

Answer 24

Contiguous spread from intrapulmonary infection (most common). Lymphatic or hematogenous spread from distant sites. Extension from infections below the diaphragm (e.g., liver abscess).

Question 25

Describe the macroscopic & microscopic appearance of empyema.

Answer 25

Macroscopic: Loculated, yellow-green creamy pus. Microscopic: Masses of neutrophils with other leukocytes.

Question 26

What are possible outcomes of empyema?

Answer 26

Resolution (less common). Organization of exudate → Dense fibrous adhesions → Obliteration of pleural space. Envelopment of lungs → Restricted pulmonary expansion.

Question 27

What are the types of inflammatory pleural effusions?

Answer 27

Serous. Sero-fibrinous. Fibrinous (severe exudative reaction, later stage).

Question 28

What are some causes of serous or sero-fibrinous pleuritis?

Answer 28

Lung inflammatory diseases: Tuberculosis, pneumonia, lung abscess, bronchiectasis. Autoimmune diseases: Rheumatoid arthritis, lupus. Uremia or systemic infections. Radiation therapy for lung/mediastinal tumors.

Question 29

What causes true hemorrhagic pleuritis?

Answer 29

Hemorrhagic diathesis. Rickettsial diseases. Neoplastic involvement of the pleural cavity.

Question 30

What are some DD of pleuritis?

Answer 30

Haemorrhagic Pneumothorax

Question 31

What does true hemorrhagic pleuritis manifest by?

Answer 31

Sanguineous inflammatory exudates.

Question 32

What is chyle composed of?

Answer 32

Cholesterol, triglycerides, chylomicrons, fat-soluble vitamins, and lymph.

Question 33

What are chylomicrons, and how are they transported?

Answer 33

Chylomicrons are molecular complexes of proteins and lipids synthesized in the jejunum and transported via the thoracic duct to circulation.

Question 34

What does lymph contain?

Answer 34

Immunoglobulins, enzymes, digestive products, and lymphocytes.

Question 35

Describe the pathogenesis of chylothorax.

Answer 35

Leakage of thoracic duct → Chyloma (fluid below pleura). Chyloma bursts through pleura → Chyle accumulates: In pleural space → Chylothorax. In mediastinum → Chylomediastinum. In pericardium → Chylopericardium.

Question 36

What are the clinical features of chylothorax?

Answer 36

Rapid loss → Hypovolemia, respiratory difficulty. Loss of protein, fats, & vitamins → Malnutrition. Loss of electrolytes → Hyponatremia, hypocalcemia. Loss of Igs & lymphocytes → Immunosuppression. Dyspnea, chest pain, and cough.

Question 37

What are the most common localizations of chylothorax?

Answer 37

Right-sided effusion: 50% (duct damage below the 5th thoracic vertebra). Left-sided effusion: 33.3% (duct damage above the 5th thoracic vertebra). Bilateral effusion: 16.66%.

Question 38

What investigations are used for chylothorax?

Answer 38

Thoracentesis & laboratory analysis. CT of abdomen & thorax: Detect tumor or lymphadenopathy. Lymphangiography: Locate site of leakage/blockage. Cytological analysis with Sudan III stain: Detect chylomicrons.