pleural effusion

Question 1

definiton

Answer 1

= excess collection of fluid in pleural space- can restrict expansion of lung

theres excess fluid in pleural space cos..

1. too much fluid = produced

• <25g/L of protein = transudate [high hydristatic, low onccotic pressure]
• >35g/L of protein = exudate [high cap permeability eg due to infection]

2. too little = drained away
   * lymphatic effusion

Question 2

what is light’s criteria

Answer 2

Light’s criteria is used to differentiate between an exudate and transudate pleural effusion

in order to apply Light’s criteria, the total protein and LDH should be measured in both blood and pleural fluid

pleural fluid is an exudate if one or more of the following are met

• pleural fluid protein divided by serum protein is >0.5
• pleural fluid lactate dehydrogenase to serum lactate dehydrogenase ratio >0.6
• pleural fluid level more than two thirds of the normal upper value for serum lactate dehydrogenase as determined locally

Question 3

aetiology of exudate pleural effusion

I.N.I.I

Answer 3

[due to increased cap permeability eg due to inflammation

1. infection - pneumonia/TB
2. neoplasm- bronchial, lymphoma, mesotherlioma
3. inflammation- RA/SLE
4. infarction

Question 4

aetiology of trasudate pleural effusion

“CRAHM”

Answer 4

[too much fluid leaves capillaries], high cap hydrostatic pressure, low oncotic pressure]

1. CCF

heart cant pump [HF]-> blood backs up-> pulm htn -> fluid pushed capillaries into pleural space

2. renal failure

3. low albumin
   eg. cirrhosis, liver failure, nephrosis, enteropathy

4. hypothyroidism

5. meigs syndrome

• right pleural effusion
• ascites
• ovarian failure

Question 5

LYMPHATIC PLEURAL EFFUSION- DEFINE THE CAUSE

Answer 5

aka chylothorax

cause:

• iatrogenic during surgery
• tumour [lymphoma]

Question 6

s/s

Answer 6

sympmtoms

• asympto
• dyspnoea upon lying flat [orthopnoea]
• pleuritic chest pain

signs: [tesa bro VR]

• t - trachial deviation away from the effusion
• e- decreased expansion
• s- strong dull percussion
• a- decreased air entry
• bro- bronchial breathing just above effusion
• VR- decreased VR

+ s/s of associated disease:

• ca = cachexia, clubbing, HPOA, radiation burn, lymph nodes
• chronic liver disease
• cardiac failure
• RA/ SLE
• hypothyroidism

Question 7

ix

Answer 7

1. bloods - fbc, u+e, lft, tft, ca, esr
2. PA CXR- blunt costophrenic angles, mediastinal shift away
3. US - recommended-> increases likelihood of successful pleural aspiration. detects pleural septations.
4. contrast CT- helps identify cause esp exudative effusions
5. diagnostic pleural tap/aspiration

• US guided
• 21G needle + 50mL syringe
  • send for pH
  • protein
  • LDH
  • cytology
    
    • tells you if transudate/exudate
    • diagnostic pleural sampling = needed for PLEURAL INFECTION [ie. all pts with pleural effusion + pneumonia/sepsis]

Question 8

what is analysed in pleural fluid analysis

Answer 8

Gross appearance of the pleural fluid should be recorded in order to identify potential aetiologies:

• putrid odour - anaerobic empyema
• food particles – oesophageal
• anchovy brown fluid - ruptured amoebic abscess
• bile staining - cholothorax (biliary fistula)
• milky - chylothorax/pseudochylothorax
• black fluid – Aspergillus infection (1,2)

Pleural fluid tests include:

• recommended for all samples
  
  • biochemistry - LDH and protein, blood should be sent simultaneously to biochemistry for total protein and LDH so that Light’s criteria can be applied
  • microbiology - for microscopy, culture and sensitivities, in case of suspected pleural infection, additional samples of blood culture bottles should be sent
  • cytological examination and differential cell count - refrigerate if delay in processing anticipated (eg, out of hours)
• additional tests for selected cases
  
  • pH - in non-purulent effusions when pleural infection is suspected
  • glucose - low in effusions due to rheumatoid arthritis, tuberculosis, SLE and malignancy
  • gram and auramine (or Ziehl-Neelson) stain
  • triglycerides and cholesterol - to differentiate chylothorax from pseudochylothorax in milky effusions
  • amylase - occasionally useful in suspected pancreatitis-related effusion.
  • haematocrit- diagnosis of haemothorax

Question 9

what are some characteristic pleural fluid findings

Answer 9

low glucose: RA, TB

increased amylase: pancreatitis, oesophageal rupture

heavy blood staining:

1. mesothelioma
2. PE
3. TB

purulent, turbid, cloudy: INFECTION - place chest tube and allow drainage

clear fluid but pH <7.2: suspect infection- place chest tube

Question 10

mx

Answer 10

1. rx underlying cause
2. recurrent drainage
3. indwelling pleural catheter
4. dx and rx to alleviate sumptoms eg. opioids to releive dyspnoea [or surgery = last option..]
5. chemical pleurodesis if recurrent malignant effusion

• procedure to achieve symphysis between the two layers of pleura by sclerosing agent