Lecture 18 - Respiratory 4

Question 1

What is the function of the parietal pleura?

Answer 1

Parietal - Lines thoracic wall, diaphragm, mediastinum Visceral - covers lung surface These are also lined by mesothelial cells - apical villi these allow active transport of ions and macromolecules

Question 2

What should be in the pleural space under normal physiologic conditions?

Answer 2

Normally contains trace amounts of clear fluid - this acts as a lubricant - it is low protein and low cellularity

Question 3

What is the condition seen below and what is the prevalence of the condition seen below in domestic animals?

Answer 3

Neoplasia - Mesothelioma - Rare in domestic animals

• It can be congenital in calves

Question 4

What is the name of the condition that is shown below and wha is is a combination of then:

1. Provide an example of a bacteria that could cause this
2. State the clinical signs that may be seen

Answer 4

Pleural inflammation = pleuritis, fibrinous, supprative, granulomatous combination

Supprative pleural exudate = pyothorax (it is usally septic, extension of pneumonia - fibrinous pleuropneumonia)

1. Could be potentially caused by a streptoccocus species
2. Painful (contributes to respiratory signs, chronic pleuritis - fibrinous pleural adhesions (obstruct lung inflation)

Question 5

Name the condition shown below and provide an example of a bacteria that could cause it:

Answer 5

Fibrinous pleuritis - Streptococcus equi equi

(note above the absence of inflammation within alveolar spaces next to the pleural surface)

Question 6

For the image below state:

1. Diagnosis
2. Potential bacterial agent
3. A likely pathogenesis

Answer 6

1. Supprative and haemorrhagic pleuritis
2. Neocardia, actinomyces, bacteroides
3. Pathogenesis is poorly characterised - bite wounds or penetrating foreign material (grass awns)

Question 7

For the image below:

1. State the condition
2. What is the pathogenesis?
3. A potential cause
4. What are the clinical signs that are seen?

Answer 7

1. Pneumothorax - air in the thoracic cavity
2. Loss of normal negative pressure required for inspiration and lung expansion
3. Secondary to pulmonary or thoracic wall disease - penetrating thoracic wall trauma, oesphageal/tracheal rupture, ruptured lung bullae, barotrauma (high air pressure as a result of anaesthetic equipement failure)
4. Atelectasis - respiratory distress, the animal is unable to expand its own lungs, reduced breath sounds with resonant percussion

Question 8

Name the condition below, then:

1. Define the term
2. Explain the clinical signs that would be seen

Answer 8

Pleural effusion

1. Accumulation of fluid in thoracic cavity - can be transudate, modified transudate, exudate, blood, lymph, chyle
2. Excessive pleural fluid accumulation causes compressive atelectasis - respiratory distress - restrictive pattern of inspiratory dyspnoea, rapdi shallow respiration and reduced intensity of breath sounds

Question 9

Name the condition below. (and define) and provide a potential aetiology:

Answer 9

Haemothorax - blood within the thoracic cavity

Aetiology:

• rupture of a major vessel
• coagulopathies - anticoagulent, DIC
• ruptured haemangiosarcoma/heart base tumour

= typically acute and fatal

Question 10

Name the condition that is shown below and:

1. Provide an aetiology
2. State a potential cytological finding

Answer 10

This is a chylothorax: Chyle = lymph rich in triglycerides.

1. This has arisen from lymphatic vessel rupture either of the thoracic duct or right lymphatic duct - usually idiopathic in dogs, caused by thoracic neoplasia, trauma, lymphangitis, congenital lymphatic vessel anomalies
2. On cytology a large number of lymphocyte would be seen