Lecture 27 - Pleural Pathology Flashcards
What are the most common pleural pathology?
Inflammation - pleurisy or pleuritis
Fibrosis
Neoplasia
What are the causes of pleural inflammation?
Primary inflammation diseases Infections Pulmonary infarction Emphysema Neoplasms Therapeutic Iatrogenic
How can primary inflammatory diseases cause pleural inflammation?
Collagen vascular diseases such as SLE and rheumatoid arthritis
What infections can cause pleural inflammation?
Usually secondary to pneumonias or pulmonary tuberculosis.
Viral - primary Coxsackie B infection (Bornholm disease)
How can a pulmonary infarction be a cause of pleural inflammation?
usually secondary to pulmonary arterial thromboembolus
How can emphysema cause pleural inflammation?
secondary to ruptured bullae
How can neoplasms cause pleural inflammation?
Primary or secondary pleural neoplasms
what are neoplasms?
a new and abnormal growth of tissue in a part of the body, especially as a characteristic of cancer.
What therapy can be a cause of pleural inflammation?
pleurodesis usually with talc to treat recurrent pleural effusions or recurrent pneumothoraxes.
What are the iatrogenic causes of pleural inflammation?
Radiotherapy to the thorax immune reactions to a drug
What signs and symptoms would you diagnose pleural inflammation with if there is no associated pleural effusion?
Sign - Auscultation of a pleural rub during breathing
symptom - pleuritic chest pain, a sharp localised pain exacerbated by breathing
What is pleural fibrosis?
Usually secondary to pleural inflammation.
- Unilateral of bilateral
- Localised or diffuse
Asbestos associated pleural fibrosis
- Parietal pleural fibrous plaques
- Diffuse pleural fibrous
The effects of pleural fibrosis?
Widespread thick fibrosis can prevent normal expansion and compression of the lung during respiration causing breathlessness.
Fibrous adhesions can wholly or partly obliterate the pleural cavity
Removal of the fibrous tissue (pleural decortication) can improve the expansion and compression of the lung during respiration.
What is removal of fibrous tissue called?
pleural decortication
What does pleural decortication do?
can improve the expansion and compression of the lung during respiration
What are parietal pleural fibrous plaques?
Associated with low level asbestos dust exposure
Asymptomatic
May be visible on chest radiographs
Dense poorly cellular collagen
Why are parietal pleural fibrous plaques not eligible for Industrial Injuries Disablement Benefit?
Not a UK Government Prescribed Occupational Disease for specified high exposure occupations.
Pathological fluids in the pleural cavities
Serous fluid
pleural effusion
Pus in the pleural cavity
empyema or pyothorax
when does empyema or pyothorax occur usually?
usually secondary to pneumonia
Blood in pleural cavity
haemothorax
What causes a haemothrorax
usually traumatic or a ruptures thoracic aortic aneurysm
Bile in pleural cavity
chylothorax
what can cause a chylothorax
usually trauma
Gas in the pleural cavity
pneumothorax
What are the 2 types of pleural effusions?
Transudates or exudates
What are transudates?
- Low capillary oncotic (colloid osmotic) pressure and/or high capillary hydrostatic pressure
- Intact capillaries retain semipermeability
- Low protein (<2.5 g/dL) & low lactate dehydrogenase
What are exudates?
- Pathological capillaries loose semipermeability
- Normal capillary oncotic pressure and normal vascular hydrostatic pressure
- High protein (>2.9 g/dL) & high lactate dehydrogenase
What are exudates?
- Pathological capillaries loose semipermeability
- Normal capillary oncotic pressure and normal vascular hydrostatic pressure
- High protein (>2.9 g/dL) & high lactate dehydrogenase
Causes of transudates?
High vascular hydrostatic pressure
- Left ventricular failure, renal failure
- Low capillary oncotic (colloid osmotic) pressure
- Hypoalbumenaemia - hepatic cirrhosis, nephrotic syndrome
Causes of exudates?
Inflammation with/without infection
Neoplasms either primary or secondary
What are the signs and symptoms of pleural effusions?
Symptoms
- Breathlessness - effusion compresses the lung
- Little/no pleuritic pain - the visceral and parietal pleura are not in contact
Signs
- Percussion - dull
- Auscultation - reduced breath sounds
What are the investigations to support the diagnosis?
Imaging - ultrasound, chest, radiograph, CT
Treatment for pleural effusions
Treat the breathlessness by removing the fluid
- aspiration with a needle and syringe, ultrsound guided
- reaspirate if the fluid reaccumulates
- For recurrent effusions consider a temporary or permanent pleural drain
- For recurrent effusions when the lung expands after drainage and the underlying cause remains consider pleurodesis to obliterate the pleural cavity
What is pleurodesis?
Pleurodesis is a medical procedure in which the pleural space is artificially obliterated.[1] It involves the adhesion of the two pleurae.
It is not a curative treatment, but rather an approach that is recommended when symptoms like chest pain and shortness of breath are causing discomfort.
What are the local and systemic causes for pleural effusions and how would they be treated accordingly?
Local
- Pleural fluid for cytology, microbiology, & biochemistry
- Pleural biopsy
Systemic
- Investigate the systemic causes of pleural effusions
What is a pneumothorax?
Air in the pleural cavity
What is an open pneumothorax
- A chest wall perforation usually traumatic - a “sucking chest wound’ - connects the body surface to the pleural cavity
- External air is drawn into the pleural cavity during inspiration, reducing potential lung expansion
What is a closed pneumothorax
- A lung perforation, usually not traumatic, connects the lung air spaces to the pleural cavity
- Lung air is drawn into the pleural cavity during inspiration, reducing potential lung expansion
What are the causes of a closed pneumothorax?
- Ruptured emphysematous bullae - as in picture left
- Common inflammatory lung diseases
- Asthma, pneumonia, tuberculosis, cystic fibrosis
-Traumatic - lung tears from fractured ribs
- Iatrogenic
- Mechanical ventilation at high pressures
- Lung and pleural biopsy procedures
- Some rare cystic lung diseases - Langerhan’s cell
histiocytosis, lymphangioleiomyomatosis
- Catamenial due to pleural endometriosis
what is a tension pneumothorax?
Perforation into a pleural cavity in an open or a closed pneumothorax can be valvular, letting air into the cavity on inspiration but not letting air out.
Pressure can rise above atm pressure - blowing up a balloon.
Can compress mediastinal structures including the vena cavae and heart and move the mediastinum compressing the contralateral lung.
A tension pneumothorax is potentially fatal and requires urgent treatment
How would you diagnose a pneumothorax?
Symptoms - small may be asymptomatic
- breathlessness
- Pleuritic chest pain
Signs
- Cyanosis
- Tachychardia
- Contralateral tracheal deviation in tension pneumothorax
- Percussion -hyper resonant
- Auscultation - reduced breath sounds
Investigations to support the diagnosis
- imaging - ultrasound, chest radiograph, CT
- symptomatic pneumothoraces are often initially treated without further investigation
What’s the treatment for a pneumothorax?
- May resolve spontaneously
- A tension pneumothorax can be decompressed as an emergency procedure using a needle inserted via an intercostal space
- With an open pneumothorax the penetrating chest wound causing it can be covered with an occlusive adhesive dressing that may incorporate a valve to allow air our but not in
- For any pneumothorax a chest drain tube can be inserted incorporating a valve to allow air out but not in while the pneumothorax resolves.
- For recurrent pneumothoraces pleurodesis is usually considered.
What are the 2 types of pleural neoplasms?
Primary
- Benign/low grade malignant - uncommon/rare
- Includes low grade mesothelial tumours
- Malignant
- Malignant mesothelioma - common
- Others - uncommon/rare
- Secondary malignant
- Carcinomas - breast, lung, others - common
- Others - lymphoma, melanoma, others
What are malignant mesotheliomas
A neoplasm of the mesothelial cells that line serous cavities - pleura, peritoneum, pericardium, tunica vaginalis
- 92% are pleural, 8% are peritoneal
- Both are commoner in men
Peritoneal - effect higher proportionof women, having a higher proportion of low grade type and are less strongly associated with asbestos dust exposure
- Both are commoner in men
-Tend not to metastasise widely
What do early malignant mesotheliomas do?
A small tumour can produce a large pleural effusion.
The tumour can be difficult to identify on imaging and therefore it is difficult to target biopsies at it.
Malignant cells may be shed into the effusion therefore effusion cytology may allow an early tissue diagnosis to be made.
Malignant mesothelioma histology
- Mixed tubulopapillary epithelioid and spindle cell sarcomatoid morphology
- Can be either type alone
- Can be poorly cellular - ‘desmoplatic’
- The main morphological differential diagnosis is malignant mesothelioma or non-small carcinoma
Histology of malignant mesothelioma
Tubules of solid aggregates of malignant mesothelial cells
The morphological differential diagnosis is adenocarcinoma or epithelioid malignant mesothelioma
Immunostaining of malignant mesothelioma
Uses antibodies linked to a dye to identify antigens in cells
Mesothelial cells and epithelial cells tend to express different antigens so can be differentiated
-cross reaction so a panel of 4 or more antibodies is used
what stains on the left?
Mesothelium-associated antigen
What stains on the top?
Cytokeratin 5
What stains on the middle?
Wilms tumour antigen
What stains on the bottom?
Calretinin
what is the major cause of malignant mesothliomas?
- Asbestos - 80 to 90% of cases
strong association above general population exposure level but exposure can be low level
link identified first in south african asbestos mining towns in 1960
develops over 15-60 years after exposure
risk increases with cumulative exposure level and time from exposure
estimated 1-2 spontaneous cases per million persons per year
- Thoracic irradiation
- BAP1 (BRCA1 - associated protein 1) mutations
- Germline mutations in a familial cancer syndrome with uveal melanoams and mesotheliomas
What is asbestos?
Fibrous metal silicates
5-100mm x diameter 0.25-0.5 mm
What are the different types of asbestos?
Blue - amphibole ( crocidolite)
Brown - amosite
White - serpentine (chrysotile)
What happens when fibrous metal silicates are inhaled?
They become coated with mucopolysaccharides containing iron to form asbestos bodies
How can asbestos bodies be identified?
Can be seen in tissue sections by light microscopy, brown when unstained or blue if the iron is stained, and quantified - a cheap simple process
How can asbestos fibres be quantified in lung extracts?
By electron microscopy - expensive process
Which type of asbestos is most oncogenic?
Blue asbestos/crocidolite which are amphiboles
what type of asbestos is less oncogenic?
white asbestos/ chrysotile and is more readily cleared from the lung
Why and what is the cause of a very high incidence of mesotheliomas in young people of Cappadocia?
Erionite is a fibrous zeolite mineral that has a fibre structure similar to asbestos. It is used as a building material in Turkey.
How is asbestos used?
A fire proof material widely used in commercial and domestic buildings and in ship building from the 1940’s and to the 1990’s
Between 1940 and 1998 there were 5.5 million tons of asbestos imported into the UK
Crocidolite and amosite imports were banned in 1985 and all asbestos imports were banned in 1999
What is asbestosis?
Interstitial pneumonia-like progressive pulmonary interstitial fibrosis caused by high level exposure to asbestos dust
What occurs during asbestosis?
Fibrosis of the alveolar walls impairs both gas exchange and lung expansion and contraction during breathing.
Is asbestosis related to the pleura or the lung?
lung
What is virchows triad
Virchow’s triad or the triad of Virchow describes the three broad categories of factors that are thought to contribute to thrombosis.
Hypercoagulability Haemodynamic changes (stasis, turbulence) Endothelial injury/dysfunction
