Pleural effusion Flashcards
What are the methods by which a transudate/ modified transudate can be made?
- Increased capillary hydrostatic pressure
- Decreased intravascular oncotic pressure
- Impaired lymphatic drainage
- Increased capillary permeability
What are the classifications of pleural effusion?
Systemic: - Transudates - Modified transudates Local: - Septic and non septic exudates - Chylous - Haemorrhagic - Neoplastic
What laboratory analysis should be performed on an effusion
EDTA for cell counts Serum gel tube Plain tube for culture In house cytology Particularly helpful when infection, inflammation or neoplasia are possible
How much fluid is needed to cause respiratory distress?
30-60ml
How can ultrasound examination help?
Direct thoracocentesis
Transudates usually anechoic
Haemorrhage, chyle and pus usually echoic usually echoic
Pleural thickening & septation may suggest:
▪ chronic inflammation
▪ Mesothelioma?
Outline pyothorax
Normally cause unknown, can be d/t bite/ trauma/ FB
Can be insidious cause, presentation quite delayed and slow
Abscence of bacteria does not exclude - need to do culture!
What are the most common bacterial isolates of a pyothorac
Anaerobic bacteria and gram positive filamentous organisms (Actinomyces/ Nocardia) most common in dogs
Pasteurella/ anaerobes most common in cats
What bedside lab tests can you do to suggest a pyothorax?
Glucose < 1.7 and pH <6.9 is suggestive
How do you treat a pyothorax>
Amox clav or MTZ with another good
Bilateral chest tubes - want the tip at the second rib space
Lavage and drain until clear - BID (roll around to move fluid)
Normally needs to be in for approx 7d.
In some cases medical oral management can cure
What is the px for pyothorax
0- 40% mortality
If no improvement within 48- 72 hours - surgical exploration for FB
Outline chylethorax
Results when chyle from the cisterna chyli-thoracic duct system gains access to the pleural space
Chyle is a milky fluid consisting of lymph and emulsified fats
Fluid drained from the mesenteric lymphatic vessels to a large lymphatic saccular reservoir
What is the thoracic duct?
continuation of the cisterna chyli that returns lymph from intestine intestine to the venous system via a lymphaticovenous junction in the cranial thorax
What is the aetiology of chylethorax
Transmural leakage or chyle or trauma Most commonly idiopathic Or secondary to: Heart disease Neoplasia ▪ thoracic wall, lymphatic or mediastinal Vena caval thrombosis Lung lobe torsion PPDH Congenital abnormalities of the thoracic duct
How do you diagnose chylethorax?
Chyle is typically white or pink-white
Anorexic patients may have clear effusion
Fluid triglyceride concentration > serum triglyceride concentration
Fluid cholesterol < or = to serum cholesterol
How do you ix chylethorax
Look for cause with imaging - u/s, rads
cytological exam will help to rule out neoplasia
How do you treat chylethorax medically?
Repetitive thoracocentesis
Rutin
low fat diet
Not always successful
If medical management of chylethorax doesn’t work, what should you do?
Ligation of caudal thoracic duct
The rational is this will lead to the formation of new lymphaticovenous anastamoses as a result of blocking the flow of chyle into the thorax
Succes = <60% dogs
21-53% cats
Sometimes failure is d/t failure to ligate all the collateral branches of the TD, increaed RHS venous pressures, pulmonary lymphatic fluid production, pleuritis
Concurrent pericardial thickening may impede lymphatic drainage - pericardiectomy sometimes performed at the same time
What are the main causes of haemothorax?
trauma coagulopathy neoplasia parasites lung lobe torsion
How do you dx haemothorax
Blood without plateles, doesn’t clot, but PCV same as body
How do you manage haemothorax>?
If mild, manage conservatively - absorbs in 90 hours
Moderate - partial thoracocentesis, consider auto transfusion (if not neoplastic)
What are the main neoplasias causing pleural effusion?
lymphoma
metastatic carcinoma
thymic most common in cats
How useful is cytology in neoplastic effusions?
If roun cell normally quite good, harder with epithelial
hard to dx mesothelioma - often needs a pleural biopsy
How do you treat neoplastic effusions
Lymphoma- systemic tx
intracavitary can be used for mesotheliomas and carcinomas
Can sometimes drain and leave ports in
What is a tension pneumothorax?
One way valve created - leads to death
What can cause a pneumothorax?
Blunt trauma
penetrating injuring
iatrogenic following FNA/ Sx? Biopsy
Spontaneous - from bulla, leaking via abscess or neoplasia, migrating FB
How do you treat a pneumothorax?
Drain if dyspnoeic / recurrent
Tx initialing cause
Sx if no cuase obvious/ recurrent
What are idiopathic effusions?
inflammatory exudate
many will have un dx mesothelioma or metastatic carcinoma
What are the misc causes of effusions
FIP - Pyogranulomatous inflammation
- IFAT on macrophages from effusions has a moderate
sensitivity and high specificity for diagnosis
Idiopathic - steroids may help
