Pleural Disease Flashcards
(57 cards)
What are the 2 types of pleura found in the lung and what structures do they cover?
visceral pleura
- covers lungs and forms fissures
parietal pleura
- covers mediastinum, diaphragm, inner surface of thorax
The most inferior part of the pleura extends down to below the inferior lung border. TRUE/FALSE?
TRUE
How much fluid is usually found in the pleural cavity?
4mls
need >200mls for it to be detected on a CXR
How does the inferior part of the pleura (which extends beyond the lung) attach to the diaphragm?
- pleural layers combine to form the pulmonary ligament
- this attaches the root of the lung to the diaphragm.
What is a pleural effusion?
Abnormal collection of fluid in pleural space
Pleural effusions do not always need drained. TRUE/FALSE?
TRUE
- e.g. in cardiac failure this may be the new “normal” for the patient
When should a pleural effusion raise concern?
Large unilateral collection of fluid
How can a pleural effusion be investigated?
- PA CXR
- Pleural aspirate
- Biochemistry (is it a transudate or an exudate?)
- Cytology and culture
Bilateral pleural effusions point towards what diagnoses?
Bilateral – LVF, PTE, drugs, systemic path
The colour of a pleural effusion can point towards a diagnosis. Give examples of this.
Straw-coloured => cardiac failure, hypoalbuminaemia
Bloody => trauma, malignancy, infection, infarction
Turbid/Milky => empyema
Foul smelling => Anaerobic empyema
Food particles => oesophageal rupture
What is the difference between a transudate and exudate pleural effusion?
Transudate - Protein <30g/L
Exudate - Protein >30g/L (should point towards more serious pathology)
What are the main causes of a transudate pleural effusion?
- Heart failure
- Liver cirrhosis
- Hypoalbuminaemia
- Lung Collapse (ITU or post surgery)
- Peritoneal dialysis
CAUSES AREN’T ALWAYS BENIGN
What are the main causes of an exudate pleural effusion?
- Malignancy
- Infection inc TB
- Pulmonary infarct
- Asbestos
Why is checking the pH of pleural fluid useful?
- Normal 7.6
- <7.3 suggests pleural inflammation (malignancy/ RhA)
- < 7.2 NEEDS DRAINED (if infection suspected)
- Do not check pH if frank pus! **
What is the relevance of measuring glucose in pleural fluid?
- LOW in many cases (being used up by organism/ tumour)
- infection/TB
- rheumatoid arthritis/SLE
- malignancy
- oesophageal rupture
Often pleural protein is not expressed as an amount, instead it is compared to serum protein. Over what ratio would pleural protein be considered abnormal?
Pleural protein: serum protein ratio >0.5
What other component of pleural fluid is compared to the level in serum to differentiate between transudate/exudate?
LDH
if Pleural LDH: Serum LDH ratio > 0.6
=> exudate
How can cytology on pleural fluid aid diagnosis?
- Malignant cells present indicating cancer?
- Lymphocytes present?– TB, malignancy, or just longstanding effusion
- Neutrophils = acute process
Why is thoracocentesis often repeated?
- Pleural aspiration diagnoses malignancy in 60% with malignant pleural effusion
- 2nd sample increases yield slightly,
- No further samples increase yield
It is difficult to diagnose mesothelioma from pleural fluid aspiration. TRUE/FALSE?
TRUE
- positive result obtained < 1/3 of cases.
How can a malignant lung tumour cause a pleural effusion through “systemic” means?
- Pulmonary embolism
- hypoalbuminaemia
How can a malignant lung tumour cause a pleural effusion locally?
- postobstructive infection
- ymphatic obstruction
- atelectasis (collapsed lung)
What type of biopsy is taken to aid diagnostic sensitivity when looking for pleural disease?
Image (CT) guided cutting needle pleural biopsy
increases diagnostic sensitivity to 87%
What is mesothelioma?
- malignant tumour of the lining of the lung
- occasionally of the lining of the abdominal cavity
- takes 30–40 years to develop
- associated with asbestos exposure => patients can gain compensation
