The Pleura

Question 1

What is malignant mesothelioma?

Answer 1

Cancer of the pleural cells

Question 2

How much pleural fluid do you have?

Answer 2

15-20ml

Question 3

How is pleural fluid produced? Which layer produces most?

Answer 3

Through filtration, the parietal pleura produces more, mainly just due to the forces on the pleural membranes

Question 4

What cells are in the pleural fluid?

Answer 4

Macrophages, lymphocytes usually filtered out from blood and mesothelial cells shed from peural surface

Question 5

What pressure is the pleura at? Is there a gradient?

Answer 5

Negative pressure, yes, most negative at the base of the lung (-5) compared to -3 at the top

Question 6

Differences pleural effusion/pneumothorax/harmothorax/empyema

Answer 6

pleural effusion - fluid in pleural space
pneumothorax- air in pleural space
harmothorax - blood in pleural space
empyema - pus in pleural space

Question 7

What causes pleural effusion?

Answer 7

An imbalance in production and absorption of pleural fluid

Question 8

What is transudate vs exudate

Answer 8

Different types of pleural fluid:
Transudate = think translocated, the cause is generally not lung related, more watery secretion (low protein, non inflammatory), produced purely through filtration
Exudate = wanted to exit real fast, high protein(3g/deciliter), high immune cells

Question 9

What is Lights criteria

Answer 9

Distinguishes between transudates and exudates.
Compares plasma fluid to serum fluid for:
Protein concentration, lactate dehydrogenase and fluid.

Question 10

What are causes of transudates? Is effusion usually bilateral/unilateral?

Answer 10

Common causes include organ failure eg heart failure, liver failure, kidney failure.

Presents often as bilateral effusions, often have subcutaneous oedema/fluid elsewhere in body too.

Question 11

Common causes of Exudate

Answer 11

Pulmonary causes eg parapneumonic effusion associated with pneumonia.

Also can be secondary malignancy

Pulmonary emboli/clots in the lungs or benign asbestos effiusions.

Question 12

Can an ultrasound be easily used bedside to monitor?

Answer 12

Yes

Question 13

How much fluid is needed to be visible on CX

Answer 13

100-200ml

Question 14

What is a loculation?

Answer 14

A small fluid pocket usually only picked up on CT scans. Usually likely to be infected or about to form pus.

Question 15

How do you take pleural fluid sample?

Answer 15

With a simple green needle, sometimes under local anasthetic. An ultrasound will mark the spot.

Question 16

Why do you need to drain fluid pH 7.2+ in pneumonia?

Answer 16

Likely to form PUS, infection more difficult to control.

Question 17

Which protein and carb levels do we look for?

Answer 17

LDH - Lactacte dehydrogenase and glucose levels

Question 18

What is a pneumothorax?

Answer 18

Air in the pleural space

Question 19

Spontaneous pneumothorax can be caused by what? Who in usually? Presentations? Signs?

Answer 19

usually tall and thin men (primary spontaneous pneumothorax) - or those with pre existing lung disease (2ndry spontaneous pneumothorax) eg COPD. caused by “blebs” on lungs - which are weak spots which can spontaneously rupture.

Sudden onset of chest pain and SOB

Tachypneic, tachycardia, resonant chest, hypoxia

Question 20

What is Iatrogenic caused by usually?

Answer 20

Some sort of healthcare intervention, eg biopsy/mechanical ventilation

Question 21

What is tension pneumothorax? Is it a life threatening event?

Answer 21

When the trachea becomes deviated to one side and the air compresses all the structures over.

yes, life threatening because can compress heart, so less bp drops, compression of opposite lung can mean that o2 levels fall. Can escalate quickly to cardiac arrest.

Question 22

Why are smaller pneumothoraxes easily missed?

Answer 22

Because they are generally at the apices (air rises) of the lungs, harder to see on X-Ray due to lots of other structures being there (clavicle, first rib)

Question 23

What are the management options for pneumothorax?

Answer 23

Depends on condition of patient:

Observe (small pneumothorax, patient is well)

Aspiration (needle with syrynge to suck out air) - small pneumothorax but over 2cm in size, patient well

Chest drain insertion - usually left in place until pneumothorax completely resolves, common for large secondary pneumothoraxes

If it is the 2nd pneumothorax patient has had surgery may be best option as unlikely to heal by itself.

Question 24

What is the recurrence rate for pneumothorax? Precautions after 1sr pneumothorax?

Answer 24

25-50%

Within 1st week of recovery from pneumothorax advised o flying and to avoid lifting heavy objects

Question 25

Where is the safe space for inserting chest drain or performing pleural procedures

Answer 25

“the triangle of safety!”

lateral boarder of lats amd axilla, level of 5th intercostal space

Question 26

How do most pleural malignancy’s present?

Answer 26

As secondary malignancies from primary cancers elsewhere. can also be primary tumours (mesothelioma)

Question 27

How common are benign pleural tumours?

Answer 27

Rare!!

Question 28

If secondary tumour in pleura, where can primary sites be?

Answer 28

Usually intra-parenchymal lung cancer, Breast, ovarian, renal, GI, thyroid

Question 29

How do secondary cancers cause plural effusion?

Answer 29

Cause pleural effusion due to blocking drainage of fluid.

Question 30

What is the pathophysiology of mesothelioma?

Answer 30

Asbestos inhaled, aggrivates parietal pleura, inflammation, repair, inflammation, repair… etc… Eventually can cause tumour formation in parietal pleura - develop into nodules on parietal pleura - presents as breathlessness/chest pain.

Question 31

Clinical examination findings fro mesothelioma

Answer 31

Clubbed nails
palpable neck nodules
signs of pleural effusion

Question 32

How is it diagnosed?

Answer 32

On biopsy

Question 33

Management of mesothelioma

Answer 33

Very much palliative;
occasionally chemotherapy drugs given, but often patient is too unwell.
Treat the effusion
Palliative surgery in select patients

Question 34

What is pleurodeisis?

Answer 34

Irritant drug in pleural space to avoid build up of fluid.