Pleural diseases Flashcards
PE
Incr resp effort and rate
May be rapid shallow respiration
May be orthopnoea, reluctant to assume position other than standing and sternal
Dullness on percussion of ventral thorax
Displacement of apex beat of heart may suggest a mass lesion
thoracocentesis
Removal of fluid from the pleural space
pleural effusion of a moderate volume
Diagnostic - obtain a sample for analysis
Therapeutic - relieve signs of respiratory distress
Techniques relying on valves and gravity can be used in horses
different types of analysis done on pleural fluid
Sample into EDTA tube for cytology and plain tube for culture/biochemical analysis
Cytology, total cell count and differential count
Total protein content
Bacterial culture and sensitivity
Gram stain
Triglyceride and cholesterol levels (if suspicious of chyle)
types of pleural fluid
Transudate (Hydrothorax) Modified Transudate Exudate (Pyothorax) Chyle (Chylothorax) Blood (Haemothorax) Air (pneumothorax)
what is transudate
Low in protein, cells + specific gravity
appears watery
Fluid forms passively, generally due to low plasma oncotic pressure
Commonly a consequence of hypoproteinaemia
what is modified transudate
more protein + cells
Cytology mixed - Macrophages, neutrophils, mesothelial cells
Grossly appears slightly turbid and pink
modified transudate - causes
Venous obstruction RCHF Neoplasia Lung lobe torsion Diaphragmatic hernia
what is exudate
high cell + protein content
exudate - septic vs non
Septic - cell type predominantly neutrophils often degenerate with bacteria present
Non-Septic - Due to vasculitis (FIP) or neoplasia
Grossly appears purulent or turbid
what is chyle
damage to the thoracic duct - Intestinal lymph drains into thoracic cavity
Grossly milky appearance
High in triglyceride
Fluid triglyceride > plasma triglyceride
Cell count and S.G. similar to modified transudate but cells predominantly lymphocytes
blood in the thorax
haemothorax
Grossly appears haemorrhagic
Usually indicates coagulopathy, trauma or neoplasia
Usually defibrinated and will not clot
Protein and cell content similar to whole blood
pneumothorax
Air in the pleural space
Usually spontaneous or secondary to trauma
Air can leak from - Lung, Mediastinum, Through thoracic wall
Small to moderate volume pneumothorax common after RTA
radiography uses
useful to confirm presence of pleural fluid and determine underlying cause, esp in small animals.
Radiography before and after thoracocentesis
May reveal changes obscured by fluid
Characteristic changes with - pneumothorax, pneumomediastinum
ultrasound
Normally little value in diagnosis of non-cardiac intrathoracic disease
The presence of fluid enhances ultrasounds utility
Sometimes allows abnormalities to be found - mediastinal + pulmonary masses, abscesses etc.
Ultrasound guidance can be used to aspirate lesions or drain pocketed pleural fluid
Equine Pleuropneumonia - causes
Mixed bacterial infection Organisms are often that are normal flora of the pharynx Beta-haemolytic Streptococcus E coli Klebsiella spp. Pasteurella spp. Bordatella spp. Bacteroides spp. - NB anaerobes
Equine Pleuropneumonia - Pathogenesis
Suppression of pulmonary defence mechanisms
Inhalation of bacteria with subsequent extension into pleural space
Cranioventral distribution
Equine Pleuropneumonia - clinical signs - acute
Pyrexia Lethargy Slight nasal discharge Shallow breathing Guarded cough Painful, stilted gait Pleurodynia (severe muscle pain) Pleuritic pain in the chest
Equine Pleuropneumonia - clinical signs - chronic
Intermittent fever
Weight loss
Ventral and limb oedema
Equine Pleuropneumonia - clinical signs - post-acute
Nostril flare Tachycardia Increased jugular pulse height Toxic mucous membranes Guarded, soft, moist cough Foetid nasal discharge
pleuropneumonia - diagnosis
History Clinical Signs Physical examination Haematology Ultrasonography Thoracocentesis (Radiography) Transtracheal aspirate
pleuropneumonia - auscultation
not consistent, often not useful absent airway sounds ventrally dorsal sounds may be normal or abnormal fluid in the trachea pleural friction rubs? Cardiac sounds radiate?
pleuropneumonia - treatment aims
Remove excess pleural fluid
Antibiotic therapy
Anti-inflammatory and analgesic therapy
Supportive care
pleuropneumonia - treatment - drainage - effects
removal of the restrictive forces
re-expansion of the pulmonary tissue
improves pulmonary clearance
removes debris, organisms,inflammatory mediators, toxins
pleuropneumonia - treatment - pleuroscopy
Excellent drainage
Visualisation
Break down adhesions
