intro to pleural disease Flashcards
what is a pleural effusion
a buildup of fluid between the layers of tissue that line the lungs and chest cavity; can be transudate (congestive HF, Liver cirrhosis etc.) or exudate (malignancy, infection, PE etc.)
transudate vs exudate
transuade: occurs due to increased hydrostatic pressure/low oncotic pressure, low in protein and LDH;
exudate: occurs due to inflammation and increased capillary permeability, high in protein and LDH
what criteria can be used to determine if a fluid is transudate/exudate and what is the criteria (3)
Light’s criteria - pleural fluid is an exudate if one or more of the following are met:
1. pleral fluid protein divided by serum protein is >0.5
2. pleural fluid lactate dehydrogenase (LDH) divided by serum LDH is>0.6
3. pleural fluid LDH >2/3 the upper limits of normal lab values for serum LDH
i.e. high protein and LDH levels compared to serum/normal values
what are 7 causes of transudates
top 4 are the most important:
1. heart failure
2. liver cirrhosis
3. nephrotic syndrome
4. hypoalbuminaemic states
5. mitral stenosis
6. meigs syndrome
7. constricitve pericarditis
what on the CXR can be helpful in determining if fluid is a transudate
often bilateral and right side may be larger
6 causes of pleural exudates
- parapneumonia effusions and empyema (pus in pleural space)
- malignancy
- pulmoary infarction
- TB
- drugs (e.g. Mtx, rare)
- RA - the only systemic condition to cause exudate! (usually small and resolved w RA treatment)
what are 2 red flags to look out in Hx of pleural effusion
weight loss; high risk occupation (construciton, miner etc.)
what invetigations should be done of pleural effusion is seen
bloods (FBC, U&E, LFT etc.);
CXR (PA and lat)
ultrasound - can determine fluid type and help establish trans vs exu, can determin if fluid vs thickening, check for loculations and guide theorcentesis
CT - check for malignancy
PET scan
what should be done if pleural effusion is thought to be an exudate
aspiration
what 3 samples should be sent for (of pleural effusion aspiration)
- LDH + protein
- cytology (check for cancerous cells)
- microbiology
what is the safe triangle and what are the landmarks
the are where it is safe to take a lung fluid sample from
Lateral border of pectoralis major anterior, mid-axillary line posterior, 5th intercostal space (inferior)
what is a pale yellow pleural fluid commonly indicative of
transudate (occastionally exudate)
what is a red (blood) pleural fluid commonly indicative of
malignancy, bening asbestos pleural effusion
what is a white (milky) pleural fluid commonly indicative of
chylothorax, cholesterol effusion
what is a brown pleural fluid commonly indicative of
long-standing bloody effusion; rupture of liver amebic abcess
