Spontaneous pneumothorax Tension pneumothorax Mesothelioma

1. Spr 09 1
Disorders of the pleura

2. Disorders of the pleura
• Movement of pleural fluid:
– Depends on the balance between
hydrostatic and oncotic pressures in the
capillaries in the parietal and visceral
pleura.
– Fluid normally moves from the parietal
pleura into the pleural space and into the
lungs.

3. Etiology of pleural effusion
1. Increased hydrostatic pressure in the
visceral pleura: (e.g. CHF)
2. Decreased oncotic pressure : nephrotic
syndrome
3. Obstruction of lymphatic drainage from
the visceral pleura (lung cancer)
4. Increased vessel permeability of visceral
pleural capillaries (pneumonia, pulmonary
infarction)

4. • Types of pleural effusion:
– Transudates: ultra-filtrates of plasma
involving disturbances in Starling’s forces
• Example: increased HP or decreased
COP
– Exudates: protein rich and cell rich fluid.
• Due to increase in vessel permeability
in acute inflammation.
• Example: pneumonia, infarction

5. Spr 09 5
Pneumothorax

6. Spontaneous pneumothorax
• Causes:
– Idiopathic
– Paraseptal emphysema
– Rising to surface when deep sea diving.
• Pathogenesis:
– Rupture of subpleural bleb produces a hole in the
pleura  leakage of air  pneumothorax  collapse
of lung
• Clinical findings:
– Sudden onset of dyspnea with Pleuritic type chest pain
– Tympanitic percussion note and absent breath sounds

7. Tension pneumothorax
• Causes:
– Penetrating trauma to lung (e.g. knife injury)
• Pathogenesis:
– Flap like pleural tear allows air into the pleural
cavity but prevents its exit.
– Increased pleural cavity pressure produces
compression atelectasis.
• Clinical findings:
– Sudden onset of severe dyspnea
– Tympanitic percussion note and absent breath
sounds.

8. Spr 09 8

9. Mesothelioma
• Primary malignant tumor of the pleura that
encases the lung
• Majority associated with asbestos exposure
(usually Amphiboles).
• Produce a restrictive type of lung disease and
present with massive pleural effusion.
• EM: long microfilaments and abundant
tonofilaments.
• Prognosis : extremely poor.

10. Morphology
• Grossly
– Yellow-white firm mass that
– Obliterates the pleural cavity and
– Encases and compresses the lung
• Histology: biphasic pattern**
– Carcinomatous component (spaces and cleft
lined by atypical epithelium)
– Sarcomatous component.
• Remember: Smoking does not increase the risk
of developing mesothelioma

11. Spr 09 11
Mesothelioma

12. Spr 09 12
Disorders of the Respiratory tract
The End