Radiological findings of pleural effussion

Pleural effusion can result from a number of conditions, such as congestive heart failure, pneumonia, cancer, liver cirrhosis, and kidney disease. [1] The characteristics of the fluid depend on the underlying pathophysiologic mechanism. The fluid can be transudate, nonpurulent exudate, pus, blood, or chyle. Imaging studies are valuable in detecting and managing pleural effusions but not in accurately characterizing the biochemical nature of the fluid.

1. DR ARPAN SINGH CHOUHAN RADIOLOGICAL FINDINGS OF PLEURAL EFFUSION

2. Fluid in the pleural space can adopt several different appearances on both erect and supine cxr’s. The commonest appearance is an opaque meniscus at the costophrenic angle.

3. Frontal xray It requires approx 200 – 300 ml of pleural fluid to efface the normal shape recess between diaphragm and ribs. If the effussion is very large the entire hemithorax may be opaque and heart may be pushed towards normal side

4. Types of frontal xrays Lamellar- A lamellar shadow paralleling the lateral aspect of lung.

5. ENCYSTED – loculation within a fissure or elsewhere.eg. Heart failure.

6. SUBPULMONARY - Pulling within the pleural space below lung. Common occurrence Easier to detect on left side because gastric air bubble appears widely separate from the superior margin of the diaphragm.

7. Supine xrays When the patient is supine pleural fluid layers out in the posterior part of pleural space. This causes hemithorax to appear whiter or pallor grey than the normal side. Approx 200 ml fluid has to be present for the abnormal pale grey appearance.

8. Lateral decubitus Earliest to catch up effusion. 150 ml of fluid can be detected in this type of effusions.

9. A Frequent Puzzle A patient is very ill, xray shows basal shadowing. IS IT FLUID OR CONSOLIDATION.

10. ANSWER- In Practice pts have some pleural fluids and some have lung consolidation On supine xray it is very difficult to determine if the shadowing is predominantly fluid. If thoracocentensis is considered as therapeutic option then ultrasound will confirm significant volume of pleural fluid alternatively and lateral decubitus xray wilol usually clearify .

11. White out lung Completely white hemithorax is often referred as whiteout lung, may be caused by large volume of pleural fluid 5-7 litre. Frontal xray reveals homogenous opacity of all or most of one hemithorax.

12. Causes of whiteout Large pleural effussion with minimal or moderate secondary compression of underlying lung. Large pleural effussion with major secondary compression of underlying lung. Collapse of entire lung. Previous pneumanectomy. Extensive pneumonia involving entire lung. Extensive tumour infiltration of lung (rare) Congenital abscess of lung (very rare)

13. Differential diagnosis: Mediastinum Trachea Interpretation Opposite side Central or deviated to opposite side Large effussion with minimal secondary compression collapse of the underlying lung central No deviation Large effussion with major collapse of the underlying lung Ipsilateral side Same side Collapse of entire lung, minimal or no pleural fluid. *RIBS missing/distorted Pneumonectomy.

14. Clinically Xray USG Minimal 500 150 (lateral Decubitus) >50 Mild 300 50 - 100 Moderate 100 - 5000 Massive 5000 - 7000

15. HRCT Displaced crus sign : Pleural fluid may collect posterior to diaphragmatic crus and therefore displaces crus anteriorly whereas ascites collects anteriorly and there is a posterior displacement.

16. Diaphragm sign : As an extention of displaced crus sign, any fluisd that is on the exterior to the dome of diaphragm is in the pleura and if it is inside the diaphragm than it is ascites.

17. Interface sign: the interface between liver and spleen and pleural fluid is said to be less sharp than between liver and spleen and ascites.

18. Bare area sign: The peritoneal coronary ligament prevents ascitic fluid extending over posterior surface of liver whereas in pleural fluid may extend over the entire posterior costophrenic recess behind the liver.

19. Pleural diseases 1. Pleurisy 2. Pleural effusion. 3. Pneumothorax 4. Haemothorax

20. Parenchymal diseases Interstitial lung diseases. Pulmonary fibrosis Diffuse parenchymal lung disease Inorganic causes: Silicosis Asbestosis Berylliosis

21. Organic causes: Hypersensitive pneumonia Connective tissue and autoimmune diseases. Infection Atypical pneumonia Pnemocystitis pneumonia Tuberculosis

22. Pleural fluid pathology : 10 ml in each cavity Composition is same of plasma Formation is dependent on Hydrostatic pressure Plasma oncotic pressure Permeability of capillaries

23. Examination of pleural fluid Transudative Exudative Appearance Colourless Straw coloured, Haemorrhagic Consistency Normal Turbid Chemical examination Sr LDH Fluid ldh Fluid protein

24. Cell count Less than 1000 (lymphocytic predominance) More than 1000 (inflammatory)
(*very high neutrophilic count more than 50000 in empyma) Specific gravity Less than 1.016 More than 1.016 Microbiological Culture sterile mostly Gram smears and cultures reveal various organisms Cytological Bronchogenic carcinoma
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