Diseases of the pleural space Flashcards
How common is pleural disease a cause of dyspnoea (SA and horses?
SA - relatively common
Horses - rare
What causes pleural disease?
wide variety of disease, generally result in the development of either fluid or air in the pleural space.
CS - pleural disease -7
- most consistent finding is dyspnoea
- Pyreixa with septic effusion
- hypoproteinaemia signs - chronic diarrhoea
- trauma - pneumothorax, haemothorax, diaphragmatic hernia
- bleeding - coagulopathy
- other signs - neoplasia
PE findings -pleural disease
- increased RR and RE, shallow
- orthopnoea
- dullness on percussion of ventral thorax (fluid)
- resonance on percussion of dorsal thorax (pneumothorax)
- displacement of apex beat of heart (mass)
- evidence of concurrent abdominal abnormalities
- other evidence of RCHF
What should you hear if you percuss a normal lung field?
Resonance (dullness indicates a problem such as fluid)
What does an ‘empty’ cranial abdomen with dyspnoea suggest?
diaphragmatic hernia
What does concurrent ascites with dyspnoea suggest
bi-cavity effusions imply a more generalised disease
How can the presence of a pleural effusion be confirmed?
- imaging (radiography or ultrasound - less manipulation so may be better for severe dyspnoea cases). THEN once confirmed, perform thoracocentesis
Indications - thoracocentesis - 3
- moderate volume pleural effusion
- diagnostic
- therapeutic
3 important technical aspects of thoracocentesis
- maintain a closed system
- maintain sterility
- cranial OR caudal to the heart.
How can you maintain a closed system with thoracocentesis?
Butterfly needle attached to an extension set with either a syringe or a 3-way tap attached to this.
How to you perform thoracocentesis in horses?
reliance on valves and gravity
How do you analyse pleural fluid?
EDTA tubes - cytology
Plain tube - culture and biochemical analysis
What do you analyse in pleural fluid? 6
- cytology, TCC and differential count
- TPC
- bacterial culture and sensitivity
- gram stain
- Tg and cholesterol levels (suspect chyle)
- NT-proBNP (cats to distinguish cardiogenic or non-cardiogenic effusions)
How are effusions classified? 2
Based on TNCC and TP
What is transudate in the pleural space called?
Hydrothorax
What is exudate in the pleural space called?
Pyothorax
What are transudates typically caused by?
hypoproteinaemia
How can exudates be classified?
Always inflammatory, determine whether septic or non-septic
List 5 causes of modified transudates?
- venous obstruction
- RCHF
- neoplasia
- lung lobe torsion
- diaphragmatic hernia
Why does chylothorax arise?
as a consequence of damage to the thoracic duct –> intestinal lymph drains into the thoracic cavity
Outline chylothorax sample
- grossly milky appearance
- high in Tg (fluid Tg > plasma Tg)
- TNCC and S.G. similar to modified transudate but cells are predominantly lymphocytes.
What does haemothorax usually indicate? 2
coagulopathy, trauma or neoplasia
Does a haemothorax sample usually clot?
NO because it is usually defibrinated since it has been in the cavity for some time. This does not usually indicate a coagulopathy.
Outline protein and cell content of a haemothorax sample.
usually similar to normal blood
Causes - pneumothorax
usually spontaneous or secondary to trauma
Where can air leak from to cause a pneumothorax?
lung, mediastinum or through the thoracic wall.