Pleural Disease Flashcards
What colour is normal pleural fluid?
Straw coloured
How much pleural fluid is contained within the average person?
0.26ml/kg/cavity.
Around 3ml total in the pleural cavity
What process produces pleural fluid?
Filtration
Which pleura produces most of the pleural fluid?
The parietal pleura
How much protein is found in normal pleura?
1.5-2g/dl
Name the cells which can be found in pleural fluid
macrophages, lymphocytes & mesothelial cells
Is pleural pressure positive or negative?
Negative
Where in the thorax is pleural pressure the most and least negative?
most negative at the apex and becomes less negative as you move down towards the lung base.
What is a pleural effusion?
A collection of fluid in the pleural space
What causes a pleural effusion?
an imbalance between production and absorption of pleural fluid
What is pleural fluid normally drained by?
pleural lymphatics in the parietal pleura
Name the two different types of pleural effusion
- transudate
2. Exudate
What is the difference between a transudate and an exudate effusion?
Transudate= non-inflammatory effusion
Exudate= Inflammatory effusion with a protein content of >3g/dl
What is the name of the criteria used to differentiate between a transudate and an exudate?
Lights Criteria
Which three things does lights criteria compare?
- serum protein to pleural fluid protein and serum lactate dehydrogenase (an enzyme found in blood and bodily fluids).
- Pleural fluid to serum fluid levels.
- The level of pleural fluid LDH as a percentage of the upper limit of normal
What are the values of the following in a pleural effusion according to Lights criteria
pleural fluid protein /serum fluid protein ratio
Pleural fluid LDH/ serum fluid LDH ratio
pleural fluid LDH
Pleural fluid /serum fluid ratio > 0.5
Pleural fluid /serum fluid ratio > 0.6
> 2/3 rd ULN serum LDH
What are the two very common causes of transudates?
- Left ventricular failure
- Liver cirrhosis
- Hypoalbuminaemia
What are the three very common causes of exudates?
- Malignancy ( Pulmonary and non-pulmonary)
- Parapneumonic effusions empyema
- Tuberculosis
What is the most useful diagnostic tool in pleural effusion?
Ultrasound
Other than ultrasound, what other imaging modalities can be used in pleural effusion
CXR
CT thorax
How should pleural effusion be managed?
- Aspirate the fluid and inspect it for blood and pus
2. Test the pH, biochem, microbiology and cytology of the fluid
if the pH of the pleural effusion is <7.2, what is required and why?
chest drain because there is a high likelihood that the fluid will become exudate (if it hasn’t already).
How is a transudate managed?
Treat the underlying cause
What is a pneumothorax?
a collection of air in the pleural space
Name the 5 different types of pneumothorax
- primary spontaneous
- Secondary spontaneous
- Traumatic
- Iatrogenic
- Tension
What is the difference between a primary and a secondary spontaneous pneumothorax?
Primary spontaneous occurs in an individual with normal healthy lungs whereas a secondary spontaneous occurs in an individual with a preexisiting lung condition
What is an iatrogenic pneumothorax?
occur as a result of a medical procedure such as lung biopsies or ventilation
What is a tension pneumothorax?
air in the pleural cavity following a pneumothorax builds up to the point where it is causing pressure and it pushes the central structures of the chest and squashes the opposite lung which can cause blood oxygen levels to drop. This also prevents proper heart filling due to pressure and causes blood pressure to drop. These factors together can escalate quickly and become life threatening
How does a spontaneous pneumothorax present?
- Sudden event
- Chest pain or breathlessness
Which demographic is most commonly affected by a spontaneous pneumothorax?
Tall thin young men
List the examination findings that point towards a pneumothorax
- Breathing fast (tachypneic)
- Hypoxic
- Reduced chest wall movement and reduced or no breath sounds
- Not uncommonly examination may be normal
What is the first line investigation into pneumothorax?
CXR
Why are small pneumothaxes difficult to spot?
because the air rises to the apices which are occluded from view by bony structures
A patient comes in with a pneumothorax. In which scenario would you simply observe?
if the pneumothorax is <2cm and the patient is <50 years old and well
A patient comes in with a pneumothorax. In which scenario would you aspirate?
if the pneumothorax is over 2cm in size and the patient is well
A patient comes in with a pneumothorax. In which scenario would you insert a chest drain??
If the patient is unwell & the pneumothorax is >2cm
In which cases of pneumothorax would surgery be recommended?
Reoccurring or unresolving pneumothorax
What advice should you give to patients after they have suffered a pneumothorax?
not to lift any heavy weights or fly for 7 days after pneumothorax has been resolved
Where should the needle be inserted for aspiration and decompression?
the 2nd intercostal space (in line with sternal angle) on the midclavicular line
Where should a chest drain be inserted?
5th intercostal space on the mid-to-anterior axillary line within the safe triangle
What is the most common pleural tumour?
Mesothelioma
What are the two main causes of mesothelioma?
- Asbestos exposure
2. Genetic mutation
What is the average time between exposure to asbestos and tumour formation?
20-40 years
Briefly explain the pathophysiology behind mesothelioma formation s a result of asbestos exposure
Inhaled asbestos fibres reach the pleura and cause inflammation which triggers repair mechanisms. There is then a repeated cycle of inflammation and repair which can provokes tumour formation.
List the 4 most significant clinical signs of mesothelioma
- Breathlessness
- Chest Pain
- Weight loss
- Clubbed (signs of a pleural effusion)
Which two imaging modalities are used to diagnose mesothelioma?
CXR and CT
Which two diagnostic processes are required in order to make a definitive diagnosis of mesothelioma?
CT thorax and biopsy
List the three ways in which a biopsy can be obtained
- blind pleural biopsy using Abram’s pleural needle
- CT or ultrasound guided biopsy
- thoracotomy
What is pleurodesis and what is its purpose?
Pleurodesis= spraying the lung with sterile talcum powder to stop fluid from reaccumulating
What is the most significant effect of mesothelioma, clinically?
Pleural effusion
What is the main focus of mesothelioma treatment?
Manage and treat the pleural effusion
Chemotherapy is rarely useful in mesothelioma patients. why?
Mesothelioma is usually diagnosed at such a late stage that chemotherapy is rarely useful
What are the palliative surgical treatments available to mesothelioma patients?
- Pleurodesis
2. Decortication
What is decortication?
peeling the layers of thickened pleura off in order to allow the underlying lung to re-expand and to relieve breathlessness
Is a mesothelioma patient entitled to compensation?
yes as it is an occupational lung disease
