Pleural effusion and OSA

Question 1

Light criteria is used to distinguish whether a pleural effusion is a transudate or exudate. Outline it

Answer 1

transudate = pleural/serum protein ratio of <0.5
= Pleural/serum LDH <0.6

Exudate = pleural/serum protein >0.5
= pleural/serum LDH >0.6

Question 2

what is another way of using LDH to determine transudate or exudate?

Answer 2

pleural LDH <2/3 normal serum LDH = transudate

pleural LDH >2/3 normal serum LDH = exudate

Question 3

what are the causes of pulmonary transudates?

Answer 3

due to increased venous pressure;

• heart failure
• fluid overload
• hypoalbuminaemia
• constrictive pericarditis

Question 4

what are the causes of pulmonary exudates ?

Answer 4

increased pleural capillary leakiness;

• TB
• pulmonary infarct
• RA and SLE
• malignancy
• PE
• post surgery

Question 5

what are the S&S of a pleural effusion?

Answer 5

commonly asymptomatic

pleuritic chest pain, SOB, cough

reduced chest expansion 
reduced vocal fremitus 
stony dull percussion 
quiet breath sounds 
large effusions can cause tracheal deviation

Question 6

what are the InV for pleural effusion?

Answer 6

CXR
- blunted costophrenic angles

Pleural US

pleural aspirate

• 10-30ml
• check protein, LDH, microbiology, cytology

pleural biopsy
- ?malignancy or TB

Question 7

what are the treatment options for pleural effusions?

Answer 7

treat cause

thoracentesis

• triangle of safety
• slow drain (0.5-1.5L over 24 hours)

02

pleurodesis
- tetracycline, bleomycin, talc

indwelling pleural catheter for recurring

Question 8

what is OSA ?

Answer 8

episodic complete or partial upper aiway obstruction during sleep associated with oxyhaemoglobin desaturation and arousal

excessive daytime sleepiness in OSA syndrome

Question 9

what are the risk factors for OSA?

Answer 9

maxillmandibular abnormalites or adenotonsillar hypertophy

anatomical narrowing of pharynx

Obesity

Question 10

what are the clincial features of OSA ?

Answer 10

obesity 
chronic loud snoring 
witnessed apnoea 
daytime somnolence 
reduced libido 
morning headaches 
fatigue

Question 11

what investigations are done in OSA?

Answer 11

clincal exam
- weight, BMI BP, neck circumference (over 40cm), craniofacial appearance

Epworth sleepiness score
STOP-BANG questionnaire
Berlin Questionnaire

Polysomnography

• 02 sats, nose and mouth airflow, ECG, EMG chest and abdo wall during sleep
• Apnoea/hypopnoea index (AHI) calculated
• AHI 5-15 = mild, 16-30 = moderate, >30 = severe

Question 12

what is the management of OSA?

Answer 12

weight loss and avoidance of tobacco/alcohol

CPAP

mandibular advancement device

sleep postion trainers for supine OSA

Question 13

what are the complications of OSA?

Answer 13

HTN
RV strain
Cardiovascular disease
increased CVA risk

DVLA must be informed if daytime somnolence. Increased risk of RTC