Lecture 17: Respiratory 2 Flashcards

1
Q

Define atelectasis

A

It is the incomplete expansion of alveoli that can affect the whole lung or just part of it

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2
Q

What is the gross appearance of atelectasis

A

dark and sunken

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3
Q

What are the types of atelectasis

A

congential

acquired
- compressive
- obstructive

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4
Q

What does congenital atelectasis indicate

A

It indicated the the neonatal lungs are not inflating

May be obstructed with meconium or amniotic fluid in the bronchi or bronchioles

If it is focal it can resolve over time

If it is diffuse it can indicate underlying problems
- acidosis/distress causing aspiration of fluid
- surfactant problems resulting in alveoli that can’t stay open (higher risk if premature

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5
Q

What might cause compressive atelectasis

A

external compression from something outside the lung in the thorax
- space occupying mass like a tumor/abccess/neoplasia
- bloat
- pyothorax

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6
Q

What might cause obstructive atelectasis

A

Blockage of airway from inside the lung
- mucus
- exudate
- aspiration

Narrowing lumen
- edema
- inflammation

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7
Q

Define emphysema

A

It is the distension and rupture of alveoli

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8
Q

How does emphysema present grossly

A

It is ‘bubbly’ and has crepitus

Due to air bubble/bullae formation in the parenchyma or connective tissue

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9
Q

What are the 2 types of emphysema and which occurs in animals

A

primary - not in animals (due to inhalation of smoke)

secondary - found in animals (secondary to disease)

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10
Q

What are 2 mechanisms that result in secondary emphysema

A
  1. obstruction to outflow
    - bronchopneumonia because the exudate acts as a 1 way valve which allows air to enter but prevent its escape
  2. agonal change
    - normal at slaughter
    - excess airway constriction from gasping against a closed airway
    - more common at the edges of the lung
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11
Q

Define pulmonary congestion

A

Passive accumulation of blood in the lungs

not the same as hyperemia

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12
Q

What might cause pulmonary congestion

A

heart failure
- stagnation of blood in pulmonary vessels can result in leakage
- intra alveolar hemorrhage

gradual causes
- DIC
- vasculitis
- septicemia
- coagulopathy

sudden = erosion of the pulmonary artery = sudden hemoptysis and death

It can also be an artifact of death via jugular cutting or blunt force trauma

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13
Q

What is the gross features of pulmonary congestion

A

heavy, edematous lungs with hemorrhagic/serosanguinous fluid that oozes when cut

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14
Q

Define pulmonary edema

A

It is the accumulation of fluid in the pulmonary interstitium and alveoli

The fluid accumulation overwhelms the macrophage’s ability to resorb
- the macrophages become less effective when they are floating

fluid leak > fluid resorb (or lymph drainage)

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15
Q

What are 2 categories of pulmonary edema

A

cardiogenic/hydrostatic

permeability/inflammatory

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16
Q

List 4 causes of cardiogenic or hydrostatic pulmonary edema

A

congestive heart failure

iatrogenic fluid overload

hypoproteinemia

reduced lymph drainage or a lymph blockage

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17
Q

List 4 causes of permeability or inflammatory pulmonary edema

A

general inflammation resulting in leaky vessels

viral or toxic lung disease

acute respiratory distress syndrome (ARDS)

shock

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18
Q

Are necropsy findings diagnostic for ARDS? If so what findings indicate this disease?

A

No cant diagnose from a necropsy alone

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19
Q

What are the gross features of pulmonary edema

A

lots of froth in the trachea (only a little froth is an agonal change at death)

failure of lung to collapse
- can see the intralobular septa and rib impressions

heavy/dark/wet
- ooze serosanguinous fluid

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20
Q

What is the histologic features of pulmonary edema

A

pink fluid in the alveoli

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21
Q

List 4 types of pulmonary embolisms and what are their features?

A

Thromboemboli (insignificant - fibrinolysis will degrade)

septic or bacterial emboli (from vegetative valvular endocarditis resulting in embolic pneumonia and abcess/hemorrhage)

fat emboli from bone fractures

tumor emboli (common)

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22
Q

How common is pulmonary neoplasia? What is a unique feature that occurs when neoplasia occurs in the lungs?

A

primary neoplasia is rare

secondary neoplasia is common

space occupying mass = hypertrophic osteopathy (symmetrical periosteal proliferation)

23
Q

An animal comes in with a lung lobe torsion. What animals is it most likely to be? What are the gross lesions?

A

deep chested dogs - usually the right middle lobe

can affect any species though

It causes pulmonary infarct and coagulation necrosis

24
Q

What causes lung lobe torsion

A

idiopathic

25
Q

What are the clinical signs of lung lobe torsion

A

if it is sterile (without bacteria) the body will wall it off and there will be very minimal clinical signs

if there is bacteria is it bad and can rupture to form a pyothorax

26
Q

List 4 causes of pulmonary mineralization

A

kidney failure and uremia

hypervitaminosis D
- rodenticide
- calcinogenic plant (solanum)

multifocal osseus metaplasia = incidental change of aging

barbiturate euthanasia

27
Q

What is the cause of smooth dark pigmented lung surface?

A

pulmonary melanosis

It is incidental

28
Q

What animals commonly have pulmonary melanosis

A

pigs, sheep, horses, goats

in the lung, GI, meninges

29
Q

What is pneumonia?

A

any inflammatory lesion

30
Q

What does the BIGE stand for

A

pneumonia classifications

bronchopneumonia

interstitial pneumonia

granulomatous pneumonia

embolic pneumonia

31
Q

What are 2 types of bronchopneumonia and their gross features

A

suppurative and fibrinous

both are usually a cranioventral distribution

suppurative causes a firm texture while fibrinous causes a hard texture

it is firm and dark like atelectasis

32
Q

What ‘portal of entry’ is primarily responsible for bronchopneumonia

A

aerosol

resulting in inflammation around the airways

33
Q

What is the distribution of interstitial pneumonia in the lungs and the gross features

A

diffuse due to inflammation of alveolar interstitium

Causes an elastic texture with rib imprints on the ‘up’ side

firm/meaty

fail to collapse

34
Q

What ‘portal of entry’ is primarily responsible for interstitial pneumonia

A

Not aerosol becaues it is not centered around the airways

mny causes
virus
toxin
allergen - antigen/Ig complex
sepsis/DIC = endothelial damage
suffocation (reduced oxygen)

35
Q

What is the pattern of distribution of granulomatous and embolic pneumonia?

A

multifocal (usually around blood vessels) nodules

either due to granulomatous inflammation throughout the lung or

inflammation in the pulmonary arterioles and capillaries (embolic)

36
Q

What ‘portal of entry’ is primarily responsible for granulomatous pneumonia

A

aerosol or blood

37
Q

What ‘portal of entry’ is primarily responsible for embolic pneumonia

A

blood

emboli
- valvular endocarditis
- hepatic abscess

sepsis
IV catheter contamination
omphalophlebitis

38
Q

Define hypostatic congestion

A

Passive congestion of the lungs that occurs when the animal has dies and is laying on the same side for a long time
- blood drains to the ‘down’ side

39
Q

What are the 4 sequelae of bronchopneumonia

A

pleural adhesions

lung abscess
- contain purulent material (can progress to caseous)

bonchiectasis
- occur due to a prior bronchopneumonia not a current one

lung sequestrum
- less common
- similar to abscess but much larger: large section of necrotic lung separated by connective tissue

40
Q

What is bronchiectasis

A

It is the most common sequelae of bronchopneumonia

It forms from the rupture and dilation of the bronchial wall due to enzymes resulting in distended bronchioles

This is irreversible collateral inflammation damage

41
Q

What are the gross and histologic features of bronchiectasis

A

It is similar to lung abscess
- full of neutrophilic purulent exudate in the airways

Histo can differentiate abscess and bronchiectasis

abcess = fibrous capsule
bronchiectasis = bronchial cartilage surrounding

42
Q

Compare fibrous and fibrinous bronchopneumonia

A

fibrous adhesions = indicated there was a prior pneumonia
- not easy to peel, has dark red/firm lung around it

fibrinous = yellow/easy to peel/acute
- indicated active fibrinous bronchopneumonia

43
Q

What comprises lung intersititum

A

endothelium
basement membrane
connective tissue

44
Q

How is interstitial pneumonia diagnosed

A

histology required

45
Q

What are 3 categories of causes of granulomatous pneumonia? Give examples.

A

phagocytic resistant bacteria - mycobacteria or rhodococcus

systemic fungal infection
- blastomyces
- coccidiodes
- histoplasma
- cryptococcus

FIP (forms granulomas around blood vessels in the lung, brain, and eyes)

46
Q

How to differentiate between granulomatous and embolic pneumonia

A

histology required

in the early stages of embolic it causes hemorrhage randomly distributed throughout the lung

47
Q

What is the primary consequence of effusive lung conditions

A

atelectasis

48
Q

List 5 types of pulmonary effusive conditions and their gross appearance

A

hydrothorax - clear fluid

pyothorax - sticks to the surface of organs and cloudy +/- colour

hemothorax - clots in thorax along with an atelectatic lung

chylothorax - white fluid that does not adhere to surfaces + clear and shiny serosal surfaces

pneumothorax - both lungs are collapsed

49
Q

On necropsy you find the thorax full of red fluid with no clots present. What is the most likely cause?

A

pyothorax

clots are required to diagnose hemothorax

50
Q

Define pleuritis

A

inflammation of the pleura

it is very painful

51
Q

What are the types of pleuritis

A

named based on the type of exudate
- fibrinous
- granulomatous
-hemorrhageic
- suppurative (due to pyothorax exudate)

52
Q

What is a common sequelae of pleuritis

A

fibrinous or fibrous adhesions

53
Q

What causes pleuritis

A

it can involve only the pleura due to hematogenous bacteria or it can be from a pneumonia (mannheimia hemolytica)

54
Q

Name a pleural neoplasia

A

mesothelioma