Unilateral pleural effusion Flashcards
Where does fluid collect?
Between the parietal and visceral pleura.
Why does fluid accumulate?
· A thin layer of fluid is always present in this space.
· If the normal flow of fluid is disrupted, with either too much produced, or not enough removed, then fluid accumulates.
· This results in a pleural effusion.
Which criteria is used for exudate/transudate differentiation?
Light’s criteria.
Who is most affected - males or females?
Equal between both sexes but also dependent on cause. Although malignancy pleural effusions more common in women due to breast/gynae malignancies.
What is the primary cause?
Imbalance between fluid production and fluid removal.
What normally happens with fluid in this space?
· 15ml/day of fluid enters this potential space, primarily from the capillaries of the parietal pleura.
· The fluid is then removed by the lymphatics in the parietal pleura.
What abnormally happens with fluid in this space?
· Disruption of fluid regulation from local or systemic derangements.
· Local factors:
- High protein and high LDH - EXUDATE.
- Leaky capillaries from inflammation (infection, infarction, tumour).
· Systemic factors:
- Low protein and low LDH - TRANSUDATE.
- Elevated pulmonary capillary pressure (heart failure, cirrhosis, nephrotic syndrome).
· In practice, transudates are often multi-factorial.
What are transudate effusions caused by?
Factors that alterhydrostaticpressure, pleuralpermeability, andoncoticpressure.
What does the pleural fluid protein have to be to diagnose a transudate effusion?
<30g/L.
What are exudate effusions caused by?
Changesto thelocalfactorsthat influence theformationand absorption of pleural fluid.
What does the pleural fluid protein have to be to diagnose a exudate effusion?
> 30g/L.
What is the aetiology?
· Rate of fluid formation is greater than that of fluid removal.
What is the aetiology of a exudative effusion?
Inflammatory processes/decreased lymphatic drainage:
· LOCAL DISEASE. HIGH PROTEIN.
· Infection - Pneumonia, empyema, pleuritis, fungal.
· Malignancy - Lung, breast, pleural.
· Vascular - PE.
· Autoimmune - RA, SLE.
· Abdominal - Pancreatitis, intra-abdominal abscess.
· Surgery - Post CABG.
What is the aetiology of a transudative effusion?
Imbalance of oncotic and hydrostatic pressures:
· SYSTEMIC DISEASE. LOW PROTEIN.
· Cardiac - CHF (elevated capillary pressures).
· Vascular - PE.
· Liver - Ascites and cirrhosis (elevated portal pressures).
· Ovarian - Meigs syndrome.
· Autoimmune - Sarcoid.
· Renal - Nephrotic syndrome (hypoalbuminaemia), peritoneal dialysis, glomerulonephritis.
List the strong risk factors.
· CHF.
· Pneumonia.
· Malignancy.
· Recent CABG surgery.