Pleural Diseases Flashcards
Pleural space
Small amount of fluid in it normally
Between visceral and parietal
Pressure in the space allows lung inflation
What lines the pleural space?
Mesothelial cells
Lymphatic openings in between allowing fluid to leave pleural space
Pleural fluid pressure
- hydrostatic pressure and oncotic pressure between parietal and visceral
- hydrostatic pressure > in parietal than visceral
- oncotic the same
- fluid into pleural space mostly from parietal through lymphatic channels
What mechanisms cause excess fluid in pleural space?
- problem with drainage of fluid via lymphatic channels
- excess production of fluid from parietal moving to space
= PLEURAL EFFUSION
What are exudates?
- local factors
- suggest protein levels are greater in fluid
What are transudates?
- systemic factors
- indicate protein levels in fluid are low
Exudate examples?
- permeable capillaries
- pleural permeability
- lymphatic drainage reduced
- increase in negative pleural pressure
What causes permeable capillaries?
- trauma
- malignancy
- inflammation
- infection
- pancreatitis
What causes pleural permeability?
- malignancy
- inflammation
- PE
What causes reduced lymphatic drainage?
- malignancy
- trauma
What causes increase in negative pleural pressure?
- atelectasis
- mesothelioma
Examples of transudates?
- increase in capillary hydrostatic pressure
- increase in pulmonary interstitial fluid
- reduced intravascular oncotic pressure
- increase in flow of fluid from other cavities
What causes increase in capillary hydrostatic pressure?
HF
What causes increase in pulmonary interstitial fluid?
HF
What causes intravascular oncotic pressure reduction?
- hypoalbuminemia
- cirrhosis
What causes increase in flow of fluid from other cavities?
- peritoneal dialysis
- cirrhosis
Symptoms of pleural effusion?
- asymptomatic
- dry cough
- breathlessness
- pleuritic chest pain
- shoulder pain/heaviness
Clinical signs of pleural effusion?
- reduced chest expansion
- reduced tactile vocal fremitus
- trachea deviation
- stony dull percussion
- reduced or absent breath sounds
- bronchial breathing?
Normal protein count in pleural space?
30g/L
> = exudate
< = transudate
Light’s criteria function
- helps to distinguish between exudate and transudate if individual has borderline pleural protein (25-30) OR abnormal serum protein
Light’s criteria for exudate
EXUDATE IF
- pleural fluid protein/serum protein >0.5
- pleural fluid LDH/serum LDH >0.6
Common Causes of exudates
- para pneumonic effusion
- malignancy
- PE
- Rheumatoid arthritis
- mesothelioma
Less common causes of exudates
- drugs
- empyema
- TB
- pancreatitis
- oesophageal rupture
- post cardiac injury (dressler’s syndrome)
- post CABG
- benign asbestos-related effusion
Common causes of transudates
- LV failure
- cirrhotic liver disease
- peritoneal dialysis
- nephrotic syndrome
Less common causes of transudates
- constrictive pericarditis
- hypothyroidism
- Meig’s syndrome
Investigations for pleural effusion
- CXR
- Pleural fluid analysis
- Chest US scan
- Chest CT scan
- pleural biopsy (image guided/medical thoracoscopy)
- video assisted thoracic surgery (VATS)
Pleural aspiration
- insert needle in safe triangle
- patient in position with arm on head OR sitting down leaning on arm with pillow or lying down on arm
Safe triangle borders
- anterior = lateral border of pec major
- posteriorly = lateral edge of lattisimus dorsi
- inferiorly = line along 5th ICS
- superiorly = axillae
Pleural Fluid analysis
- appearance
- pH
- protein
- glucose
- LDH
- cytology (malignant cells, differential cell counts)
- microbiology (gram stain and culture, AFB)
Diagnostic Algorithm
- History, exam, CXR
- clinically transudate?
How to treat transudate?
- treat cause
- see if resolved
- if not = refer to chest physician
- they will likely pleural aspirate via US guidance with other diagnostic tests
How to treat exudate?
- after done transudate investigations and ruled out
- fluid analysis
- treat cause appropriately
- CT thorax if fluid analysis doesn’t give cause
- if still uncertain = medical thoracoscopy or surgical VATS or biopsy with chest drain for symptomatic relief
VATS
- video associated thoracic surgery
- general anaesthetic
- minimal invasive
- multiple incisions between ribs
- visualise pleura and can take biopsies and drain fluid
- helps in making diagnosis
- advantage as small incisions
- less pain than traditional thoracotomy
Pleural infection presentation
- fever
- sputum
- chest pain
- breathlessness
high risk groups for pleural infection
- diabetes
- excess ETOH intake
- GORD
- IVDU
- aspiration and poor dental hygiene
- malaise/weight loss
- pleural effusion with fever
- slow response to pneumonia
Investigations for pleural infection
- diagnostic pleural tap for exudate/pus
- blood culture
- chest US
- chest CT
How may pleural infection progress?
- simple parapenumonia effusion
- complicated parapneumonic effusion
- empyema
Simple parapneumonic effusion investigation results
- ABs resolve
- fluid = clear, sterile, normal pH, glucose and LDH
- chest drain usually not required
Complicated parapneumonic effusion investigation results
- fibrinopurlent fluid
- fluid infected
- glucose <2.2
- LDH > 1000
- fluid gram stain positive
- chest drain needed
Empyema investigation results
- pus in pleural space
- free flowing
- multi loculated
- fluid gram stain positive
- fibroblasts causing thick pleura
- chest drainage required
What causes CAP?
- streptococcus (mileri, pneumoniae, intermedius) cause majority
- then anaerobes
- then staph aureus
- then gram negative aerobes (Enterobacteriaceae, E coli)
What causes HAP?
- often gram negative aerobes (E coli, pseudomonas, Klebsiella)
- staphylococci (MRSA, S aureus)
- Anaerobes
Management of pleural infection
- AB
- Chest tube drainage
- intrapleural fibrinolytics (not routine)
- nutritional support
- surgery (VATS, thoracotomy, open thoracic drainage)
Indicates for chest tube drainage in pleural infection
- purulent or turbid fluid
- pleural fluid pH<7.2
- organisms in pleural fluid gram stain or culture
Define mesothelioma
- malignant tumour of serosal surfaces
- asbestos exposure major RF
- latent >40yrs of exposure
Prognosis of mesothelioma
- poor
- 9-12 months
3 main types of asbestos fibres
- crocidolite= blue (thinnest)
- armosite = brown
- chysotile = white (most commonly used now)
Symptoms and signs of mesothelioma
- chest pain (dull ache)
- pleural effusion symptoms
- weight loss and fatigue
- chest wall invasion
Investigations for mesothelioma
- CXR and CT thorax
- pleural fluid analysis (bloody/straw coloured)
- biopsy (US or CT guided of pleura OR medical thoracoscopy or VATS)
CXR of mesothelioma
- loss of volume
- pleural effusion
- pleural thickening
Histological types of mesothelioma
- epithelioid (better prognosis)
- mixed (biphasic)
- sarcomatoid
Management of mesothelioma?
- pleural effusion = drainage and pleurodesis
- radiotherapy = pain relief and reduce chest wall invasion risk
- chemo
- surgery (high mortality, selected cases)
- pain relief
- palliative care
- compensation for asbestos exposure
Chemo for mesothelioma
- cisplatin with pemetrexed or gemcitibine
