Pleural Malignancy and Disease

Question 1

describe pleural anatomy

Answer 1

serous membranes
the visceral pleura covers the lungs and forms interlobar fissures
the parietal pleura covers the mediastinum, diaphragm, and inner surface of the thorax
inferior margins of the pleura considerably lower than the corresponding border of the lung
usually contains approx 4mls (depending on weight)
need approx 200ml x fluid to be detected on plain chest x-ray

lubricates the 2 pleural surfaces
allowing the pleura to slide smoothly during respiration
surface tension allows lung surface to stay touching thoracic wall, creating a seal between 2 surfaces
2 layers combine around the hila of the lung - so the hila have no pleural coverage
the pleural layers combine to form the pulmonary ligament, which runs inferiorly and attached the root of the lung to the diaphragm

Question 2

describe pleural effusion

Answer 2

abnormal collection of fluid in pleural space
common presentation of numerous diseases
does not always require drainage or sampling (e.g. cardiac failure)
large unilateral effusions should raise concern

Question 3

describe the workup of pleural effusion

Answer 3

PA chest x-ray
pleural aspirate (if not convincingly cardiac failure)
biochemistry;
transudate - protein <30 g/l, does not always have a benign aetiology
exudate - protein>30 g/l, always look for serious pathology (malignancy, infection (TB), pulmonary infarct, asbestos)
cytology
culture
other tests - contrast enhanced CT chest, repeat pleural tap, pleural biopsy (blind or thoracoscopy)

Question 4

describe pleural fluid appearance

Answer 4

straw-coloured e.g. cardiac failure, hypoalbuminaemia
bloody e.g. trauma, malignancy, infection, infarction
turbid/milky e.g. empyema, chylothorax
foul smelling - anaeoribc empyema
food particles - oesophageal rupture
bilateral - LVF, PTE, drugs, systemic path

Question 5

describe the biochemistry of pleural effusion

Answer 5

fluid pH;
<7.3 = pleural inflammation (malignancy)
<7.2 = requires drainage in the setting of infection
glucose;
low in infection, TB, rheumatoid arthritis, malignancy, oesophageal rupture, SLE

Question 6

describe cytology and cell counts

Answer 6

mostly looking for malignant cells (2 samples will dx up to 2/3 malignant effusions)
lymphocytes - think TB, malignancy, although any long standing effusion will eventually become lymphocytic
neutrophils suggest acute process

Question 7

describe the microbiology

Answer 7

gram stain and microscopy
culture
PCR, AFB stain and liquid culture
put in blood culture bottle for higher yield

Question 8

describe pleural tap

Answer 8

total pleural protein - 43 g/l
pleural LDH 240 iu/l
culture - no growth of pathogenic bacteria
this is a cellular sample consisting entirely of macrophages and degenerate mesothelial cells
no evidence of malignancy is seen

Question 9

describe thoracentesis

Answer 9

removes excess fluid, pleural effusion, from pleural space
pleural aspiration will diagnose malignancy in approximately 60% of patients with malignant pleural effusion
a second sample may increase the yield slightly, third and subsequent samples are non-contributory
increasing the volume of aspirate does not increase yield
pleural fluid cytology has an even poorer diagnostic yield in mesothelioma in which a positive result in obtained in less than a third of cases

Question 10

describe tissue biopsies

Answer 10

blind percutaneous pleural biopsy - abrams
image (CT) guided cutting needle pleural biopsy
thoracoscopy
thoracotomy

Question 11

describe ancillary effusions

Answer 11

systemic tumour effects - embolism, hypoalbuminaemia

local tumour effects - post obstructive infection, lymphatic obstruction, atelectasis

Question 12

describe mesothelioma

Answer 12

uncommon malignant tumour of the lining of the lung or very occasionally of the lining of the abdominal cavity
likelihood of developing mesothelioma increases with the degree and the length of time exposed to asbestos
occasionally may occur in people who have not worked with asbestos but have been associated with people who have
takes 30-40 years to develop
may cause breathlessness, chest pain, weight loss, fever, sweating, cough

Question 13

describe asbestos

Answer 13

chrysotile - white, most common
amosite - brown
crocidolite - most dangerous

Question 14

describe investigations of mesothelioma

Answer 14

imaging - pleural nodularity, circumferential pleural thickening, local invasion, lung entrapment
pleural fluid aspiration - low cytological yield, avoif repeated aspiration
biopsy - thorascopy or CT/US guided

Question 15

describe treatment of mesothelioma

Answer 15

pleurodese effusions 
radiotherapy
surgery 
chemotherapy
palliative care
report deaths to fiscal

Question 16

describe malignant pelural effusions

Answer 16

virtually all cancers may metastasize to the plerua especially;
lung cancer
breast cancer
upper GI, lymphoma, melanoma, ovary 
median survival 3-12, large variation

Question 17

describe the treatment for malignant pleural effusion

Answer 17

nothing, palliate symptoms 
repeated pleural taps
drain and/or pleurodesis (talc slurry or during thoracoscopy)
long term pleural catheters
surgical options (abrasion, pleurectomy)

Question 18

describe talc

Answer 18

sclerosing agent - irritates lining of chest cavity, causing cavity to close as there is no space or fluid

complications;
minor pleuritic pain and fever
pneumonia (rare)
respiratory failure (rare)
talc pneumonitis/ARDS (rare)
secondary empyema (rare)
local tumour implantation at port sight mesothelioma 

treatment - poudrage/insufflation (thoracoscopic instillation)

Question 19

describe long term pleural catheters

Answer 19

designed to allow patients control their effusion and therefore symptoms
inserted mostly in patients with malignant effusions
drain is designed to remain in place for life though some people will stop producing pleural fluid (never drain more than 1 litre a day)

complications - incorrect placement, bleeding, infection (patients still able to shower, bath and swim)

Question 20

describe survival time for malignant pleural effusion

Answer 20

LENT score;
LDH
ECOG PS
(serum) neutrophil to lymphocyte ratio
tumour type

Question 21

describe primary and secondary pneumothorax

Answer 21

primary;
normal lungs
apical bullae rupture

secondary;
underlying lung disease (COPD)

Question 22

describe the presentation of pneumothorax

Answer 22

primary spontaneous - asymptomatic even if moderately sized
secondary spontaneous - symptomatic even if small

acute onset pleuritic chest pain 
SOB, hypoxia 
signs;
tachycardia 
hyper-resonant percussion note 
reduced expansion 
quiet breath sounds on auscultation 
Hamman's sign

Question 23

describe the management of pneumothorax

Answer 23

oxygen even if no drain
no treatment if asymptomatic and small
aspiration 1st line in PSP;
avoids chest drain 
time consuming 
may fail especially if age>50 or SSP
chest drain 
may need suction 
surgical intervention

Question 24

describe tension pneumothorax

Answer 24

emergency - can lead to cardiac arrest
one way valve, progressively increasing pressure in pleural space
pushes other chest organs to opposite side to affected side
acute respiratory distress
signs - trachea deviated to opposite side, hypotension, raised JVP, reduced air entry on affected side

ventilated patient (invasive or not)
CPR esp PEA
blocked, kinked, misplaced drain 
pre existing airways disease
patients undergoing hyperbaric treatment

Question 25

describe treatment of tension pneumothorax

Answer 25

needle decompression;
usually with large bore venflon
second intercostal space anteriorly, mid-clavicular line

Question 26

describe pleural infection

Answer 26

increasing incidence esp extremes of age
significant mortality
does not always follow pneumonia
can rapidly coagulate and organise to form fibrous peels even with antibiotics
do not let the sun set on a potentially infected pleural space

simple parapneumonic effusion
compicated parapneumonic effusion
empyema (pus)
-quickly sample pleural fluid to identify effusion that require urgent tube drainage

Question 27

describe the risk factors of pleural infection

Answer 27

diabeteres mellitus 
immunosuppression including corticosteroids 
gastro-oesophageal reflux 
alchol misuse 
intravenous drug abuse 
*may have no apparent risk factors*

Question 28

describe pleural infection - different types of effusion

Answer 28

complicated effusion;
\+ve G stain 
pH <7.2
low glucose 
spetations 
locualtions 

simple effusion;
none of the above may be treated with antibiotics alone but may need drainage later on if things change

large effusion - chest drainage

small effusions may be left untapped

Question 29

describe management of pleural infection

Answer 29

antibiotics 
drain effusion as needed
early discussion with surgeon if persistent sepsis 
nutrition 
VTE prophylaxis 
role for fibrinolytics/Dnase