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
2
Q
A
Congenital melanosis
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
4
Q
A
Uremic pneumopathy: chronic renal failure - dog
5
Q
A
Pulmonary ossification
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
7
Q
What does a ventilation-perfusion mismatch cause
A
- Collapsed (atelectasis)
- Overinflated (emphysema)
8
Q
What is atelectasis
A
Incomplete distension of alveoli
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
*
- Lung has collapsed after inflation has taken place
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
11
Q
What are the 3 types of Atelectasis
A
A = normal alveoli
B = obstructive atelectasis
C = compressive atelectasis
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
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
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
15
Q
A
Congenital atelectasis: neonatal calf
16
Q
A
Aquired atelectasis: compressive
Dog with hydrothorax
17
Q
A
Acquired atelectasis: obstructive
Pig with pneumonia
18
Q
A
Diaphragmatic hernia in a cat
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
20
Q
What is alveolar pulmonary emphysema
A
Distention and rupture of alveolar walls forming variable sized air bubbles
Exacerbrated by chronic coughing
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
What is hyperaemia
* Active: increased blood in vessels as part of acute inflammation
26
What is congestion
* 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
What is pumonary congestion in heart failure
* 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
29
Acute pulonary congestion - dog
30
Chronic passive congestion - dog 'Heart failure cells' containing haemosiderin
31
What is hypostatic congestion a result of
* 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
What are the causes of pulmonary haemorrhage
* 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
Haemorrhaes - ferret lung
34
Fatal pulmonary haemorrhage from a lung abscess
35
Fatalpulmonary haemorrhage from lung abscess
36
What are the effects of pulmonary oedema
* 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
What is pulmonary oedema
* 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
Pulmonary oedema - cow
39
Pulmonary oedema - pig
40
Pulmonary oedema -pig
41
Pulmonary oedema: rat lung
42
What is pulmonary embolism
* 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
Acute to subacute embolic pneumonia, lung, dog
44
Jugular thrombophlebitis and pulmonary thromboembolism
Jugular vein and lung: cow
45
What is pleural effusions
* 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
Haemothorax - dog
47
Cylothorax
48
Fibrinous Pleuritis
49
Pyothorax: nocardiosis
50
Pyothorax
