Pathology of pleura, pleural spaces Flashcards
what is pleural effusion
Accumulation of fluid in the pleural space (normal <15ml);
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Manifestation of both primary and secondary pleural diseases
Pleural effusion is due to what?
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increased hydrostatic pressure (e.g. congestive heart failure),
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increased vascular permeability (e.g. pneumonia),
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decreased osmotic pressure (e.g. nephrotic syndrome),
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increased intrapleural negative pressure (e.g. atelectasis) or
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decreased lymphatic drainage (e.g. mediastinal carcinomatosis)
explain the serous, serofibrinous and fibrinous pleuritis
- Serous, serofibrinous and fibrinous pleuritis:
Aetiology :usually due to inflammation of the underlying lung
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Tuberculosis, pneumonia, lung infarction
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Systemic conditions e.g. Rheumatoid arthritis, uraemia, metastatic pleural involvement, radiotherapy for lung/pleural tumours
o Usually resolves with resorption of fluid +/- organisation of the fibrinous component
explain the haemorrhagic pleuritis
Sanguineous( resemblingor containing blood).
inflammatory exudate (different from haemothorax); Hemorrhagic pleural effusion is defined as an erythrocyte count greater than 100,000 cells/μl.2
uncommon and tumour involvement of the pleura must be excluded
explain the serous pleural effusion gross
This is fluid collection into a body cavity—an effusion. This is a right pleural effusion (in an infant). Note the clear reflective, pale yellow appearance of the fluid, indicative of a serous effusion.
explain the empyema (purulent pleural exudate)
Gross
Volume
Causes
Gross- Empyema, gross
This pleural surface has an overlying thick, yellow-tan purulent exudate. Adjacent unaffected lung with dark anthracotic pigment at the far right..
Causes: due to bacterial or mycotic seeding of the pleural space (e.g. spread from intrapulmonary infections or more distant sources)
o Volume is usually small and the pus gets walled off by fibrosis; usually organizes into dense, tough fibrous adhesions that obliterate the pleural space or encases the lung (empyema peel) and can restrict lung expansion
list 3 non-inflammatory effusions
Hydrithorax (serous fluid)
Haemothorax (blood)
Chylothorax (lymph fluid)
Milky white appearance due to finely emulsified fats. Usually due to thoracic duct trauma or obstruction of a major lymphatic duct (usually by malignancy)
Chylothorax (lymph fluid)
Most commonly due to heart failure; also seen in other systemic
conditions associated with generalized oedema e.g. renal failure, liver cirrhosis
Hydrothorax (serous fluid)
is a pleural fluid with blood hematocrit ratio greater than 50% . Compare to haemorrhagic effusion .Usually due to trauma, surgery or rupture of aortic aneurysm
Hemothorax (blood)
what is haematocrit
Haematocrit: /ˈthe ratio of the volume of red blood cells to the total volume of blood.
You compare which non-inflammatory effusions
Haemorrhagic to haemothorax
Explain pneumothorax and list 3 examples
- Air/gas in pleural cavity, usually associated with emphysema, asthma or tuberculosis
Spontaneous pneumothorax
Traumatic pneumothorax
Tension pneumothorax
Usually due to perforating injury to chest wall
Traumatic pneumothorax
When a pleural defect acts as an air valve allowing air entry during
inspiration but does not allow air escape during expiration, resulting in progressively increasing
intrapleural pressure that can compress and cause deviation of vital mediastinal structures away
and compress the contralateral lung
Tension pneumothorax
As a complication of any pulmonary disease that causes
emphysematous change, a communicating abscess cavity, or idiopathic (usually in young people due
to rupture of small, peripheral usually apical, subpleural blebs)
Spotaneous pneumothorax
what is pleural tumours
Secondary involvement of the pleura by metastases is more common than primary pleural tumours,
usually from lung or breast primary tumours and often producing a serous or serosanguineous pleural
effusion
where does the malignant mesotheliom arises
Malignant tumour arising from mesothelial cells lining the serous cavities
what are the risk of malignant mesothelioma
Risk factors: Asbestos exposure (long latent period; risk is not magnified by smoking, unlike
asbestos-related lung carcinomas)
explain the clinical findins of malignant mesothelioma
Clinical findings: Presents with chest pain, dyspnoea, recurrent pleural effusions. Generally poor
prognosis
explain the gross of malignant mesothelioma
- Gross: Diffuse soft greyish-pink tumour arising from either visceral or parietal pleura; usually
associated with extensive pleural effusion and direct invasion of thoracic structures
explain the microscopic appearance of malignant mesothelioma
- Microscopy: Epithelioid (60-80%), sarcomatoid (10%) or biphasic (10-15%) morphology
explain the picture of malignant mesothelioma
Malignant mesothelioma, gross
The dense, white encircling tumor mass () arising from the visceral pleura is a malignant mesothelioma.
These are big, bulky tumors that can fill the chest cavity.
The risk factor for mesothelioma is prior asbestos exposure.
Asbestosis more commonly predisposes to bronchogenic carcinomas, increasing the risk by a factor of five.
Smoking increases the risk for lung cancer by a factor of 10.
Smokers with a history of asbestos exposure have a 50-fold greater likelihood of developing bronchogenic lung cancer
picture of maligant mesothelioma microscopic appearance
Malignant mesothelioma, microscopic
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There are either spindle cells or plump, rounded cells forming glandlike configurations (▲) as shown here in the pleura.
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Cytogenetic abnormalities are often present, as arep16andTP53mutations.
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Rare, even in individuals with asbestos exposure, and are virtually never seen in individuals without a history of asbestos exposure.
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In addition to the pleura, other, less common sites of occurrence of this neoplasm are the peritoneum, pericardium, and testicular tunica.
