General Pathology Of The Respiratory Tract

Question 1

What are the types of atelectasis?

Answer 1

Primary and Secondary

Question 2

What is primary atelectasis?

Answer 2

Failure of the lung tissue to expand at birth

Question 3

What is secondary atelectasis?

Answer 3

Collapse of lung tissue which was previously expanded

Question 4

What is emphysema ?

Answer 4

Excessive air within the lungs

Question 5

What is a sign of sever emphysema?

Answer 5

Lungs fail to deflate and their are imprints of the ribs on the pleural surfaces

Question 6

What are the types of primary atelectasis?

Answer 6

Total - all dark red

Partial - some salmon pink bits = inflated

Question 7

When might you see partial primary atelectasis?

Answer 7

If the neonate has taken a few breaths then died ~10 mins after birth

Question 8

What does atelectasis look like on histology?

Answer 8

Dense lung tissue - no air spaces

Question 9

What can cause secondary atelectasis?

Answer 9

Compression

Obstruction

Question 10

What compressive conditions can cause atelectasis?

Answer 10

Haemothorax
Hydrothorax
Pneumothorax

Neoplasm
Abscess etc.

Prolonged recumbency
Prolonged abdominal distension in Large animals — BLOAT

Question 11

What obstructive conditions can cause atelectasis?

Answer 11

Foreign Body
Neoplasm
Thick secretions

Question 12

How does obstruction cause atelectasis?

Answer 12

Air diffuses out across the alveolar wall but is not replaced

Wall collapses

Question 13

What neoplastic condition could cause atelectasis?

Answer 13

Mediastinal lymphoma

Question 14

Why is atelectasis secondary to obstruction less common in small animals?

Answer 14

Better collateral air supply

Question 15

What is emphysema?

Answer 15

Excessive air in the lungs

Question 16

What are the types of emphysema?

Answer 16

Alveolar
Interstitial
Compensatory

Question 17

What is alveolar emphysema?

What is it typically caused by?

Answer 17

Permanent abnormal enlargement of airspaces distal to terminal bronchioles

Anything that causes inflammation and neutrophils
NEUTROPHIL ELASTASE
(RAO/severe equine asthma)

Question 18

What is interstitial emphysema?

Answer 18

Septal lymphatic dilated with air secondary to FORCED EXPIRATION

Question 19

Give an example of a condition that causes interstitial emphysema

Answer 19

Pneumonia in cattle

Question 20

What can cause compensatory emphysema?

Answer 20

Areas of consolidation/partial atelectasis

Question 21

What is severe equine asthma usually caused by?

Answer 21

Allergies to fungal spores in hay

Question 22

What are the main types of pigmentation seen in the lungs?

Answer 22

Melanosis - melanin in alveolar walls

Anthracosis - carbon in alveolar macrophages

Question 23

Describe the gross difference between melanosis and anthracosis

Answer 23

Melanosis - ‘splodges’

Anthracosis - ‘ sprinkled pepper’

Question 24

What is the difference between hyperaemia and congestion

Answer 24

Hyperaemia - erythema - increased arterial blood IN
= exercise, inflammation

Congestion - cyanosis - decreased venous blood OUT
= hypoxia - local obstruction, congestive heart failure

Question 25

What is cranioventral hyperaemia associated with?

Answer 25

Aspiration pneumonia

Question 26

What post mortem change is associated with dependent congestion of the lungs?

Answer 26

Hypostatic congestion (livor mortis)

Question 27

Describe the possible distributions of hyperaemia

Answer 27

Localised or diffuse

Question 28

What would diffuse congestion of the lungs indicate?

Answer 28

Cardiac failure

Question 29

When would you expect to see terminal pulmonary congestion?

Answer 29

Animals euthanised with barbituates

Question 30

How does pulmonary oedema compromise ventilation?

Answer 30

Alveoli flooded by fluid Mixes with surfactant to form foam

Question 31

What physiological features resist pulmonary oedema?

Answer 31

Tight junctions between alveolar epithelium and capillary endothelium Intra-alveolar pressure greater than interstitial pressure Lymphatic drainage

Question 32

What can cause pulmonary oedema?

Answer 32

Cardiogenic - LCHF Neurogenic - sympathetic stimulation as a result of acute brain damage Excessive IVFT Damage to endothelium or epithelium - toxic substances - smoke, paraquat (banned UK), 3-methyl indole, endotoxins - acute inflammation

Question 33

What does oedema fluid look like on histology?

Answer 33

Pale pink when stained with H&E

Question 34

What is the triad of thrombosis?

Answer 34

Endothelial injury Hypercoagulability Abnormal blood flow

Question 35

What is thrombosis?

Answer 35

Obstruction of vessels by coagulated blood components during life

Question 36

Define embolism

Answer 36

Detachment of thrombi (or bacteria, tumours etc) which become lodged in small vessels

Question 37

What is infarction

Answer 37

Death of tissue due to an interruption in its blood supply

Question 38

What can cause jugular thrombosis

Answer 38

Iatrogenic - post catheterisation

Question 39

What causes bovine malignant catarrhal fever?

Answer 39

Herpesvirus

Question 40

How can you describe a pneumonia ?

Answer 40

Based on: - distribution of changes in lungs - type of inflammatory response

Question 41

What are the main types of pneumonia?

Answer 41

Bronchopneumonia - fibrinous or suppurative Interstitial pneumonia Embolic pneumonia Granulomatous pneumonia

Question 42

how does an animal get bronchopneumonia?

Answer 42

Bacterial infection via airway

Question 43

how does interstitial pneumonia occur?

Answer 43

Haematogenous infection - viruses or toxins

Question 44

How does embolic pneumonia occur?

Answer 44

Through the blood - thrombi or bacterial emboli

Question 45

How would an animal get granulomatous pneumonia?

Answer 45

Fungal or mycobacterium

Question 46

Describe the typical distribution of bronchopneumonia

Answer 46

Cranioventral

Question 47

How could bronchopneumonia deteriorate?

Answer 47

Abscessation Pleuritis - with adhesions DEATH - hypoxia and toxaemia

Question 48

What would occur if bronchopneumonia persists?

Answer 48

BRONCHIECTASIS + fibrosis

Question 49

What is bronchiectasis?

Answer 49

Permanent dilation of some bronchi due to irreversible damage to bronchial wall

Question 50

What animals is bronchiectasis seen in as a consequence of chronic bronchitis or bronchopneumonia?

Answer 50

COWS (sheep, goats, pigs)

Question 51

What is the common appearance of bronchopneumonia in cats and dogs? Why?

Answer 51

LOBAR Lack complete lobulation and septation Can therefore easily spread throughout whole lobe

Question 52

What causes a lobar pneumonia?

Answer 52

Highly toxic bacteria e.g. Pasteurella | Aspiration

Question 53

What can cause bronchi-interstitial pneumonia?

Answer 53

Inhaled mycoplasma and some virus’s

Question 54

Describe the histology of broncho-interstitial pneumonia

Answer 54

Cuffing of airways by lymphocytes | Interstitial lymphocytic proliferation

Question 55

What is the importance of bronchi-interstitial pneumonia?

Answer 55

economic - reduced growth rates, predisposition to secondary infection

Question 56

Describe the histological appearance of interstitial pneumonia

Answer 56

Inflammatory cells in interstitium DIFFUSE distribution

Question 57

What can cause an acute interstitial pneumonia?

Answer 57

``` Infections e.g. DISTEMPER Inhaled chemicals e.g. smoke Ingested toxins e.g. paraquat or tryptophan Systemic conditions e.g. uraemia Hypersensitivity reactions e.g. lungworm ```

Question 58

What can cause chronic interstitial pneumonia?

Answer 58

Infections - Jaagsietke (retrovirus) in sheep Inhaled dust - coal dust or silica Hypersensitivity reactions - farmer’s lung

Question 59

What is fog fever? What is the causative agent?

Answer 59

Acute bovine pulmonary oedema and emphysema TRYPTOPHAN

Question 60

When is fog fever seen

Answer 60

When adult cattle moved to lush pasture in autumn

Question 61

What is the pathogenesis of fog fever?

Answer 61

Excess tryptophan in autumn grass is metabolised in the rumen to 3-methyl idole Toxic to type 1 pneumocytes

Question 62

What can you get embolic pneumonia secondary to?

Answer 62

Endocarditis Hepatic abscessation Phlebitis

Question 63

What is embolic pneumonia?

Answer 63

Pulmonary abscesses resulting from septic emboli in pulmonary vessels

Question 64

How could you tell if mycobacteria were present in a sample?

Answer 64

Stain: Z-N Acid fast will stain red

Question 65

How could you stain for fungi?

Answer 65

PAS or silver stains

Question 66

What is the predominant cell type in granulomatous pneumonia?

Answer 66

Neutrophils

Question 67

What are polyps?

Answer 67

Hyperplastic tissue Often pedunculated Secondary to chronic inflammation e.g. in cats post cat flu - feline calicivirus

Question 68

What are most common tumours which metastasise to the kings?

Answer 68

Mammary tumours Thyroid carcinoma Haemangiosarcomas Osteosarcoma

Question 69

What primary tumour tends to occur in the lungs?

Answer 69

Invasive carcinomas Occur in hilar region before spreading within the lung

Question 70

What are the malignant tumours which occur in the nasal and paranasal sinuses?

Answer 70

Carcinomas or sarcomas