Lecture 24 Flashcards

1
Q

What are congenital melanosis

A
  • Incidental finding: pig and cattle
  • Black spots
  • May be present in the meninges and intima of the aorta
  • No clinical significance
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2
Q
A

Congenital melanosis

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3
Q

What is pulmonary calcification

A
  • Occurs in hypercalcaemic states - secondary to hypervitaminosis D
  • Common sequela to
    • Uraemia from chronic renal failure
    • Hyperadrenocorticism
    • Pulmonary necrosis
  • Calcified lungs fail to collapse when thoracic cavity is opened and have a gritty texture
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4
Q
A

Uremic pneumopathy: chronic renal failure - dog

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5
Q
A

Pulmonary ossification

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6
Q

What is needed in normal lungs

A
  • Balanced ratio of volumes of air to capillary blood must be present for normal respiration
  • Air and capillary blood must be in close proximity across the alveolar wall
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7
Q

What does a ventilation-perfusion mismatch cause

A
  • Collapsed (atelectasis)
  • Overinflated (emphysema)
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8
Q

What is atelectasis

A

Incomplete distension of alveoli

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9
Q

What causes atelectasis

A
  • Congenital
    • Lungs failed to expand with air at birth
  • Acquired
    • Lung has collapsed after inflation has taken place
      • Obstructive
      • Compressive
        *
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10
Q

What will normally aerated lungs float in

A

Atelectic pieces of lung will sing in formalin

  • If neonatal animals have not breathed at birth
  • If older animals have acquired atelectasis
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11
Q

What are the 3 types of Atelectasis

A

A = normal alveoli

B = obstructive atelectasis

C = compressive atelectasis

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12
Q

What is congenital atelectasia

A

Lungs failed to expand with air at birth

  • Failure of lungs to expand is often because of obstruction with amniotic fluid or meconium
  • Also occurs if alveoli fail to stay inflated because of altered qualtiy and quantity of pulmonary surfactant produced by type 2 pneumonocytes and club cells
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13
Q

what are the 2 forms of acquired atelectasis

A

Compressive atelectasis

  • Pressure from outside the lungs
  • Space occupying masses in pleural cavity
  • Transfered pressure
    • Bloat
    • Hydrothorax, haemothorax, chylothorax, pyothoras
    • Loss of negative pressure becuase of pneumothorax, diaphragmatic hernia

Obstructive atelectasis

  • Obstruction of airways within lungs
  • Reduction in airway diameter
    • Mucosal oedema or inflammation
  • Blockage of airways
    • Mucus plugs, exudate, aspirated foregin material, lung worm
  • Occurs when large animals are recumbent for long periods of time
    • Due to a combination of mucus not being drained from bronchioles and alveoli, blood-flow imbalances, shallow breathing, inadequate surfactant
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14
Q

What is the appearance of atelectasis

A
  • Depressed below the adjacent surfact of normal lung
  • Dark blue/red in colour
  • Multifocally distributed
  • Lobular
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15
Q
A

Congenital atelectasis: neonatal calf

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16
Q
A

Aquired atelectasis: compressive

Dog with hydrothorax

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17
Q
A

Acquired atelectasis: obstructive

Pig with pneumonia

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18
Q
A

Diaphragmatic hernia in a cat

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19
Q

What is Pulmonary Emphysema

A
  • Excessive air in the pulmonary system
    • Alveolar or interstitial
  • Always secondary to obstruction of outflow of air or agonal at slaughter
  • Frequently secondary to bronchopneuonia where exudate partly blocks bronchi and bronchioles
  • Can be classified as alveolar or interstitial
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20
Q

What is alveolar pulmonary emphysema

A

Distention and rupture of alveolar walls forming variable sized air bubbles

Exacerbrated by chronic coughing

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21
Q

What is intestinal pulmonary emphysema

A
  • Air bubbles in interstitial tissues
    • Mainly occurs in cattle because of lack of collateral ventilation and wide interlobular septa
22
Q
A

Bovine Interstitial Emphysema

23
Q
A

Bovine Interstitial Emphysema

24
Q
A

Bovie Interstitial Emphysema

25
Q

What is hyperaemia

A
  • Active: increased blood in vessels as part of acute inflammation
26
Q

What is congestion

A
  • Passive: decreased outflow of venous blood as occurs in congestive heart failure
  • Stagnation of blood in vessels leads to oedema and regression of erythrocytes into alveoli
27
Q

What is pumonary congestion in heart failure

A
  • What is alveolar macrophages phagocytose erythrocytes ​
    • When severe, many macrphages with brown pigment accumulate in bronchoalveolar space
    • Lungs have a patchy red and brown apperance
    • In chronic caseslungs fail to collapse due to odeam and fibrosis
28
Q
A
29
Q
A

Acute pulonary congestion - dog

30
Q
A

Chronic passive congestion - dog ‘Heart failure cells’ containing haemosiderin

31
Q

What is hypostatic congestion a result of

A
  • Gravity and poor circulation
    • Built up of blood on the lower lung of animals in lateral recumbency for a lonf period
      • Seen in cattle and hoses
      • May also have hypostatic odema and affected animals are prone to disruped defense system and infection
32
Q

What are the causes of pulmonary haemorrhage

A
  • Trauma
  • Coagulopathies
  • Disseminated intra-vascular coagulation
  • Septicaemia
  • Rupture of a major pulmonary vessel may occur in association with lung abscess
  • Excercise-induced pulmonary haemorrhage in race horses following excerecise
33
Q
A

Haemorrhaes - ferret lung

34
Q
A

Fatal pulmonary haemorrhage from a lung abscess

35
Q
A

Fatalpulmonary haemorrhage from lung abscess

36
Q

What are the effects of pulmonary oedema

A
  • Hydrostatic oedema
    • Mostly left sided heart failure
    • Fluid in alveoli
  • Iatrogenic fluid overload
  • Reduced blood osmotic pressure
    • Hypoalbuminaemia secondary to
      • Hepatic failure
      • Nephrotic syndrome
      • Protein losing enteropathy
  • Inflammatory oedema
    • Oedema accompanies many viral infections and inhaled toxicants
      • Type 1 pneumoncytes are highly vulnerable to damage
37
Q

What is pulmonary oedema

A
  • Grossly, lungs are wet and heavy
  • Fluid may be present in the plural cavity
  • On cut service, the lung parenchyma oozes fluid
  • In cattle and pigs, lobular pattern is accentuated due to oedema and dilated lymphatics in the interlobular septia
  • Considerable amounts of frothy fluid in the trachea and bronchi
38
Q
A

Pulmonary oedema - cow

39
Q
A

Pulmonary oedema - pig

40
Q
A

Pulmonary oedema -pig

41
Q
A

Pulmonary oedema: rat lung

42
Q

What is pulmonary embolism

A
  • Vast vascular network means the lung catches many emboli
    • Most common are thromboemboli, bacterial emboli, fat emboli and tumour emboli
    • Sources include valvular endocarditis, hepatic abscess, septic arthritis and omphalitis in farm animlas, fat from bone fractures
    • Dirofilaria immitis and angiostrongulus vasorum in dogs
43
Q
A

Acute to subacute embolic pneumonia, lung, dog

44
Q
A

Jugular thrombophlebitis and pulmonary thromboembolism

Jugular vein and lung: cow

45
Q

What is pleural effusions

A
  • Hydrothorax
    • Heartfailure, hypoproteinaemia, obstructed lymphatics, increased vascular permeability
  • Haemothorax
    • Trauma, coagulopathies, aortic rupture
  • Chylothorax
    • Lymph rich in lipids from ruptured thoracic duct
  • Pyothorax
    • Purulent material: bacterail infections
46
Q
A

Haemothorax - dog

47
Q
A

Cylothorax

48
Q
A

Fibrinous Pleuritis

49
Q
A

Pyothorax: nocardiosis

50
Q
A

Pyothorax