Pleural Space Disease

Question 1

What is the pleura?

Answer 1

Inner wall of body cavities lined by single layer of mesothelial cells
Visceral pleura - pulmonary side
Parietal pleura - medasinal, diaphragmatic, costal
Contains rich lymphatic system which drains pleural cavity
0.1ml/kg of fluid to allow smooth movement of lungs in breathing
Has negative pressure so fluid wants to pool

Question 2

Mediastinum

Answer 2

Space between left and right pleural sacs
Contains heart and major vessels

Question 3

What is pleural space disease?

Answer 3

Accumulation of fluid, air or soft tissue mass
Severity depends on amount
Causes direct compression of lungs and leads to negative pressure loss (lungs collapse)

Question 4

Clinical signs of pleural space disease

Answer 4

Short, shallow breathing
Tachypnoea
Open mouth breathing
Orthopnoea - using body to breathe
Cyanosis if severe

Question 5

What is pleural effusion?

Answer 5

Fluid in pleural space surrounding lungs

Question 6

Types of pleural effusion

Answer 6

Transudate (low protein, low cellularity
Modified transudate (high protein, moderate cellularity )
Exudate (High cellularity and variable protein)

Question 7

Reasons for pleural effusion

Answer 7

Increased fluid formation
Decreased fluid absorption

Question 8

Causes of Increased fluid formation

Answer 8

‘leaky’ capillaries - Pleural inflammation
Increased IV pressure - CHF
Increased lung interstitial fluid - CHF
Decreased pleural pressure
Increase in pleural fluid protein
Disruption of thoracic duct or blood vessels

Question 9

Causes of decreased fluid absorption

Answer 9

Obstruction of lymphatic drainage
Increased systemic vascular resistance (RSHF)
Reduced vascular oncotic pressure (hypoalbuminaemia)

Question 10

Causes of transudate pleural effusion

Answer 10

Protein losing enteropathy
Losing protein from guts/kidneys
Liver problems
Insufficient dietary protein

Question 11

Causes of modified transudate

Answer 11

Increased hydrostatic pressure secondary to right sided heart failure
Forcing blood through capillaries with high pressure
* Pericardial disease
* Cardiomyopathy
* Pulmonary hypertension
* Pulmonic stenosis
Diaphragmatic hernia
lung lobe torsion

Question 12

Causes of non-septic exudate effusion

Answer 12

FIP
Neoplasia
Chronic chylothorax
Chronic lung lobe torsion
Fungal infection

Question 13

Causes of septic exudate effusion

Answer 13

Penetrating wound
Foreign body inhalation
Ruptured oesophagus
Haematogenous bacterial spread

Question 14

Causes of chylothorax

Answer 14

Disruption of thoracic duct
* neoplasia
* Heart disease
* Fungal infection
* Diaphragmatic hernia

Question 15

Causes of haemothorax

Answer 15

Trauma
Coagulopathy
Neoplasia
Lung lob torsion

Question 16

Initial management for patient with suspected pleural effusion

Answer 16

Oxygen supplementation and careful monitoring
Emergency thoracic ultrasound
NO RADIOGRAPHS IF SEVERELY DYSPNOEIC
Thoracocentesis to stabilise for further investigation

Question 17

Thoracocentesis

Answer 17

Local anaesthetic can be used
Clip and surgical scrub of area
Use butterfly needle/catheter at ICS 6-8
Slight negative pressure on insertion
Use 3 way stopcock
Aseptic technique

Question 18

Indications for using a chest drain

Answer 18

If multiple thoracocentesis will be required
Large volumes of effusion
Pneumothorax
Chest wall injuries
Bite wounds
Pyothorax

Question 19

What is Pneumothorax

Answer 19

Air in pleural space

Question 20

Causes of pneumothorax

Answer 20

Rupture of major airways/lung parenchyma
Thoracic trauma (broken rib)
Perforation of oesophagus
Iatrogenic - ventilation under GA

Question 21

Clinical signs of pneumothorax

Answer 21

○ Restricting breathing pattern
Short, shallow breaths
○ Auscultation reveals dull lung sounds dorsally and increased ventrally
Opposite of pleural effusion
○ Percussion
Increased resonance

Question 22

Treatment for pneumothorax

Answer 22

○ Oxygen
○ Drain pneumothorax as necessary
○ Approx. 90% recovery with strict cage rest for up to 2 weeks
Inappropriate for some animals - welfare issue???
○ Some require chest drains and Heimlich valve
Allows air to exit but not enter
○ Surgical exploration/correction at referral level
○ If open wounds use sterile dressings