Pleural Space Flashcards
What is the pleural space and what is it filled with?
It is a very thin space between parietal and visceral pleura (0.8mm in diameter) and it is filled with a small amount of fluid (capillary film for lubrication).
What does the pleura contain?
Fluid, blood vessels and lymphatics
Is the pleural space seen radiographically?
Not normally. Seen if the pleural space is filled with fluid, cellular, or fibrinous material (pleural effusion). Seen if pleural space is filled with gas (pneumothorax), thickened pleura or deposition of calcium, infiltration of lung tissue underlying the visceral pleura.
Causes for pleural effusion
- Increased systemic venous pressure and lymphatics (R or L HF)
- Low colloidal osmotic pressure
- Increased capillary permeability due to neoplasia, infection, or trauma
- Diaphragmatic hernia with incarceration of the liver
What do you need to do to definitively differentiate what kind of pleural effusion is present?
Thoracocentesis
Free Pleural Effusion
Moves freely across mediastinal separation, gravity dependent.
Trapped pleural effusion
Atypical distribution of the pleural fluid, but still moves with gravity.
Encapsulated pleural effusion - give 2 examples
Loculated fluid by fibrinous deposits or adhesions and unable to be moved by gravity (pyothorax, chronic pleuritis)
Radiographic signs of pleural effusion - Lateral View
- Interlobar fissures
- If enough fluid - Silhouette sign with Heart and/or Diaphragm (films look underexposed)
- “leafing” of the lung lobes - (retraction of lung lobes)
Radiographic signs of pleural effusion - DV/VD view
- Retraction of lung lobes form body wall
- Rounding of costophrenic angle (especially DV)
- Widening of mediastinum b/c of communication
- +/- silhouette sign with heart/diaphragm
When radiographing pleural effusion, small amounts of fluid are best seen when?
On expiration and on erect horizontal beam views; and DV might be more helpful to see pleural fissuures
What is the costophrenic angle?
Where lungs should meet the diaphragm
Causes of hydrothorax
- Heart Failure
- Hypoproteinemia
- Diaphragmatic hernia
Causes of hemothorax
- Trauma (blood clots)
- Coagulopathy (blood often does not clot)
- Neoplasia (blood does not clot - ex hemangiosarcoma)
Chylothorax presents with pathological signs of:
Often fibrosis and permanent rounding of lung lobes when chronic
Lung lobe torsion can cause a transudate pleural effusion. What lobes are most commonly affected:
Right middle and left cranial lung lobes
Lobe lobe torsion occurs most commonly in what kind of dogs?
Large breeds, deep chested dogs
Lung lobe torsion presents as:
Non-inflated lung lobe, +/- air bronchogram, pleural effusion but cannot determine all the lung lobes
Hydrothorax, hemothorax, chylothorax, neoplasia, and lung lobe torsion are all examples of what kind of pleural effusion?
transudate
Causes of pyothorax
- Systemic
- Penetrating wounds
- Foreign body
Pyothorax in the cat often involves the ______ and can be _____.
Hemithorax, restrictive
Pleuritis - radiographic appearance
Similar findings as hydrothorax with added feature of a white line around the lung due to thickened pleura. The parietal pleural thickening is best seen on the VD view between the ribs. The pleural thickening may restrict expansion of lung with resulting ‘clover-leaf.’
Pyothorax and pleuritis are examples of what kind of pleural effusion?
exudate
While a pneumothorax can cause a heart to appear elevated off the sternum on radiographs, what else can cause this impression?
When an animal is in shock - so much so that it is enough to have a small cardiac silhouette (cardiovascular shock)
