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Flashcards in Pleural diseases Deck (32):
1

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

2

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

3

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)

4

types of pleural fluid

Transudate (Hydrothorax)
Modified Transudate
Exudate (Pyothorax)
Chyle (Chylothorax)
Blood (Haemothorax)
Air (pneumothorax)

5

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

6

what is modified transudate

more protein + cells
Cytology mixed - Macrophages, neutrophils, mesothelial cells
Grossly appears slightly turbid and pink

7

modified transudate - causes

Venous obstruction
RCHF
Neoplasia
Lung lobe torsion
Diaphragmatic hernia

8

what is exudate

high cell + protein content

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

Equine Pleuropneumonia - Pathogenesis

Suppression of pulmonary defence mechanisms
Inhalation of bacteria with subsequent extension into pleural space
Cranioventral distribution

17

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

18

Equine Pleuropneumonia - clinical signs - chronic

Intermittent fever
Weight loss
Ventral and limb oedema

19

Equine Pleuropneumonia - clinical signs - post-acute

Nostril flare
Tachycardia
Increased jugular pulse height
Toxic mucous membranes
Guarded, soft, moist cough
Foetid nasal discharge

20

pleuropneumonia - diagnosis

History
Clinical Signs
Physical examination
Haematology
Ultrasonography
Thoracocentesis
(Radiography)
Transtracheal aspirate

21

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?

22

pleuropneumonia - treatment aims

Remove excess pleural fluid
Antibiotic therapy
Anti-inflammatory and analgesic therapy
Supportive care

23

pleuropneumonia - treatment - drainage - effects

removal of the restrictive forces
re-expansion of the pulmonary tissue
improves pulmonary clearance
removes debris, organisms, inflammatory mediators, toxins

24

pleuropneumonia - treatment - pleuroscopy

Excellent drainage
Visualisation
Break down adhesions

25

pleuropneumonia - treatment - drugs

Anti-inflammatory and analgesic therapy - NSAIDs, Opiates
Antibiotics - Broad spectrum, Culture and sensitivity, Anaerobes

26

pleuropneumonia - prognosis

Milder cases, diagnosed early - may return to previous career with early and aggressive therapy, Survival rates 49 – 98%
Severe - can be salvaged for breeding, months of antibiotic treatment and multiple surgeries

27

pleuropneumonia - complications

Pulmonary abscess
Cranial mediastinal mass
Pleural adhesions
Bronchopleural fistula
Constrictive pericarditis
Thrombophlebitis
Laminitis
Diarrhoea

28

problems with treatment of pyothorax by single thoracocentesis followed by systemic antibiotics

Single thoracocentesis unlikely to remove sufficient infective material
Systemic antibiotics unlikely to penetrate inspissated purulent material in pleural space
High likelihood of recrudescence

29

pyothorax - treatment with indwelling drains + systemic antibiotics

drains facilitate pleural lavage
Leave in situ for 5-7 days
More likely to remove all infective material
Lavage should facilitate antibiotic penetration
Still risk of recurrence if foreign body present to act as nidus

30

pyothorax - more invasive treatment

Exploratory thoracotomy
Debridement and lavage of thoracic cavity
Placement of indwelling drain
Greatest likelihood of success at resolving pyothorax
Perioperative morbidity and mortality

31

cylothorax - medical management

detect underlying cause - usually idiopathic
Reduce formation of intestinal lymph - Low fat diet?, MCTO, Diuresis?
Enhance reabsorbtion of fluid from pleura - Rutin (Benzopyrone)

32

cylothorax - surgical management

identify and ligate thoracic duct
redistribute pleural fluid
enhance absorption or pleural fluid
Salvage technique is pleurodesis
get pleura to adhere together destroying the space in which the fluid forms