Respiratory: Lung Disease

Question 1

How would a hypostatically congested lung appear grossly?

Answer 1

the hypostatically congest down lungs is diffusely deep red to purple while the opposite lung (up-side) is lighter in color (pink to light red)

Question 2

What is the number one cause of congestion & edema in the lungs? Name a couple others too.

Answer 2

1. Left-sided heart failure (cardiogenic edema): increased capillary hydrostatic pressure
2. Excessive fluid transfusion
3. Brain injury: systemic vasoconstriction (neurogenic edema)

Question 3

What are the causes of congestion and edema in the lungs?

Answer 3

1. Decreased hydrostatic blood pressure
2. Increased permeability
3. Decreased plasma onctotic pressure
4. Lymphatic obstruction – everyone forgets this one

Question 4

Name a cause of increased permeability and subsequent congestion and edema of the lungs.

Answer 4

Epithelial injury:

• Toxic Gases
• Toxic plants (moldy sweet potatoes, purple mint)
• 100% oxygen
• Virus infection

Endothelial injury:

• gram negative septicemia (endotoxins)

Question 5

Name a cause of decreased plasma oncotic pressure and subsequent edema and congestion of the lungs.

Answer 5

• Hypoalbuminemia and hypoproteinemia as a result of nephrotic syndrome

Anything that causes inflammation of the kidney or impairs liver function.

Question 6

Name a cause of lymphatic obstruction and subsequent edema and congestion of the lungs.

Answer 6

• Metastatic malignant melanoma
• Lymphoma
• Metatstatic hemangiosarcoma (Dog)
• Neoplastic invasion or compression of lymphatics

Question 7

What signalment is most prone to Strangles?

Answer 7

Young Horses (1-5 years)

Anorexia, fever, mucopurulent nasal discharge

Question 8

What pre-disposes a horse to Strangles infection?

Answer 8

• Recent group of large horses (show, sales barn, race, etc.)
• Prior Strangles outbreak on the farm

Question 9

Pathogenesis of Strangles

Answer 9

S. equi equi colonizes nasal mucosa –> mucopurulent rhinitis –> localizes to regional LNs (retropharyngeal and submandibular) –> abscess formation

• 20% develop Bastard Strangles = metatstatic abscesses to liver, lungs, kidney, brain, joints, mesenteric LNs

Question 10

What is the causative agent of Kennel Cough in canines?

Answer 10

Bordatella bronchiseptica

Question 11

What are the lesions assocaited with Kennel Cough?

Answer 11

• Coughing exacerbated by exercise
• Suppurative tracheobronchitis/bronchiolitis
• +/- 2˚ pneumonia (E. coli, Pseudomonas, Kelbsiella)

Question 12

Define: thrombosis

Answer 12

An irregular clot forming

Question 13

Define thromboembolism:

Answer 13

thrombus forms somewhere and travels elsewhere

Question 14

Whats more common in the lungs: thrombus or embolism?

Answer 14

embolism

Question 15

What would cause a thrombus in the lungs?

Answer 15

Thrombus 2˚ to:

• parasites
• hypercoagulation disorders
• endothelial damage

Question 16

What is a consequence of pulmonary thrombi or emboli?

Answer 16

Lung infarcts:

• Dual blood supply reduces incidence
• pre-existing lung disease increases incidence

Question 17

Describe the lesion associated with lung infarct.

Answer 17

Firm, deep red, edges of lung lobe, +/- fibrin

Question 18

What are the abnormalities of inflation?

Answer 18

Atalectasis and Emphysema

Question 19

Describe lesions associated with atalectasis.

Answer 19

too little air in the lung:

firm, dark red, usually edges of lung lobe

Question 20

Describe lesion associated with emphysema.

Answer 20

crepitus - “bubble wrap” feeling

Question 21

What is the most common cause atalectasis?

Answer 21

Obstruction: collapse of all the airways distal to the obstruction and consequential resorption of air leads to collapse.

Question 22

What are causes of atalectasis?

Answer 22

Congenital:

• Fetal - affects entirety of lung

Acquired:

• Obstructive
  
  • most common form
• Compressive
• Hypostatic

Question 23

Describe cuases of Congenital Atalectasis.

Answer 23

• Fetal - stillborn; no respiration; no lung inflation (ie: never took a breath)
• Neonatal:
  
  • Dystocia
    
    • Fetal Distress - aspiration of amniotic fluid or meconium
    • 2˚ hypoxia –> depressed respiratory centers (in CNS) –> hypoinflation
  • Inadequate production of surfactant

Question 24

Describe lesiosn associated with congenital atalectasis.

Answer 24

Deep dark red, but fleshy since never took a breath, therefore never collapsed

Question 25

Describe **obstructive atalectasis**.

Answer 25

* **Inflammatory exudate** obstructing bronchioles * _most common_ * Parasites * Neoplastics cells * start in lumen and obstruct or adjacent to airways and compress

Question 26

Describe lesions of **obstructive atalectasis**.

Answer 26

Histologic: * Inflammation with nø in bronchioles Gross: * Atalectatic lobules depressed

Question 27

Describe **compression atalectasis**.

Answer 27

External compression of the lungs caused by: * Excessive accumulation of fluids (hydrothorax), blood (hemothorax), pus (pyothorax), air (pneumothorax), chyle (chylothorax) * Space occupying lesions including _neoplasms_ or _abscesses_

Question 28

In what species does **compression atalectasis** happen most commonly? Why?

Answer 28

Lobulated lung species: _Ruminants_ and _Pigs_ and to a lesser extent horses Why? --\> They **lack good collateral ventilation**. (absence of pores between air spaces)

Question 29

Describe GROSS appearance of **atalectasis**.

Answer 29

* One or more lobes or entire lung: * Visibly collapse lobe, lobes, or entire lung * Deep red to purple * Firm to meaty * May not float in water * Lobule: * Atalectatic lobule _depressed_ (collapsed) * Deep red to purple * More prevalent in regions of lung where alvoeli are smalles and most easily compressed

Question 30

Describe MICROSCOPIC appearance of **atalectasis**.

Answer 30

* Collapse of alveolar space resulting in _alveolar septae being in close appostion without fluid or cells in collapsed spaces_.

Question 31

Define **emphysema** of the lung. What types are there?

Answer 31

Permanent excess air accumulation in the lung * Alveolar emphysema * enzymatic destruction of the alveolar walls results in excessive accumulation of air in the lungs * Insterstitial emphysema * forced expiration causes bronchiolar collapse resulting in alveolar rupture and leakage of air into interlobular septa

Question 32

What type of emphysema is more prevalent in veterinary medicine?

Answer 32

**Interstitial emphysema** **Cattle** (most common), pigs, goats

Question 33

What does alveolar emphysema mean in _veterinary medicine_?

Answer 33

the _ante mortem_ over distension of air spaces distal to terminal bronchioles

Question 34

What species is most prone to **Interstitial emphysema**?

Answer 34

**Cattle**, then sheep and pigs

Question 35

Can interstitial emphysema and lobular atalectasis occur at the same time?

Answer 35

Yes, in cattle, sheep, and pigs

Question 36

Define **bronchopneumonia**.

Answer 36

inflammatory exudate primarily located in _bronchi, bronchioles and alveolar spaces_ * _Suppurative vs Fibrinous_

Question 37

Define **interstitial pneumonia**.

Answer 37

Inflammatory exudate primarily located in the _lung intersitium_ (alveolar septae). Air spaces relatively free of exudate. * Acute vs. Chronic

Question 38

Define **pneumonia**.

Answer 38

Any inflammatory lesion in the lungs (Veterinary Medicine)

Question 39

Define **granulomatous pneumonia**.

Answer 39

_Chronic_ pneumonia characteristically composed of **epitheliod MØ and/or multi-nucleate giant cells** plus other inflammatory cells

Question 40

What organism(s) can cause **suppurative** bronchopneumonia?

Answer 40

* Pasteurella mutocida * Mycoplasma spp * E. coli * other G - bacteria

Question 41

What organisms can cause **fibrinous** bronchopneumonia?

Answer 41

* *Manheima hemolytica* (cattle) * *A. pleuopneumonia* (pigs) * *Pasteurella multocida* (chicken) * *E. col*i * chickens * dogs (toxigenic strains)

Question 42

What are the gross features of **suppurative** bronchopneumonia?

Answer 42

Lobular involvement **varies****:** **- _sharp line of demarcation_** - **_checkerboard appearance_** on cut surface - some atalectatic, some obstructed, some suppurative/inflamed

Question 43

What are gross features of **fibrinous** bronchopneumonia?

Answer 43

**Majority if lobules** or **major part of lobe inflamed**. - **_Fibrin_** in air spaces, interlobular septae, and pleural surfaces - dilated interlobular sepatae on cut surface because filled with fibrin