Pathology of the Lung Flashcards
List major causes of compressive pulmonary atelectasis (6)
- space-occupying lesions
- hydrothorax and hemothorax
- exudative pleuritis
- mediastinal and lung tumors
- diaphragmatic hernia
- abdominal distension
List major causes of obstructive pulmonary atelectasis (3)
- complete airway obstruction
- complete blockage of lobar and segmental bronchi
- bronchial obstruction by exudate, parasites, aspirated foreign material, granulomas, and tumors
List the cause of congenital pulmonary atelectasis
lungs appear as in fetus
List the major causes of pulmonary edema (5)
- increased venous hydrostatic pressure
- increased permeability of the alveolar barrier
- impaired active transport of fluid from distal airways
- reduced oncotic pressure
- lymphatic obstruction
What is the physiological significance of edema? (4)
- decreased lung elasticity
- impaired ventilation (dyspnea)
- fluid in alveoli obstructs gas exchange
- proteins in edema fluid can interfere with surfactant production
Why is infarction of the lung relatively uncommon?
it is rare because there would need to be obstruction of a large artery and inadequate collateral flow (chance of the two happening together are slim)
What is the cause of exercise-induced pulmonary hemorrhage in horses?
elevated pulmonary arterial and capillary pressures during exercise
Can epistaxis occur in exercise-induced pulmonary hemorrhage in horses?
yes but it occurs in less than 2.5% of horses
Describe the lung appearance in bronchopneumonia and what it would look like on cut surface.
- irregular consolidation and darkening of cranioventral lung
- cut surface: edema fluid and purulent exudates
Describe the lung appearance in fibrinous bronchopneumonia.
-cranioventral lesions are covered by fibrin (pleuritis)
Describe the lung appearance of interstitial pneumonia and what it would look like on cut surface.
- mild increase in firmness or rubberiness and lungs do not collapse
- pink/grey to red/grey and can have impressions from overlaying ribs
- cut surface: minimal or no exudates released
Describe the lung appearance of atelectasis
- collapse of the lung
- affected areas are depressed and red, but not firm
- can involve whole lungs, lobes, or lobules
Describe the lung appearance of edema and what it would look like on cut surface.
- distended with fluid and are heavy and slightly firmer than normal
- cut surface: clear or blood-tinged fluid expressed
Describe the lung appearance of embolic pneumonia and what it would look like on cut surface.
- multiple widely distributed white to yellow abscesses (hematogenous origin)
- cut surface: abscesses contain white pasty to viscous fluid
Describe the lung appearance of granulomatous pneumonia.
-multifocal granulomas that are caseous or noncaseous
What is the definition of interstitial pneumonia?
damage to or inflammation of the alveolar septa and interlobular septa
Give examples of agents that cause interstitial pneumonia. (5)
- viruses
- some bacteria (salmonella)
- fungi
- protozoa
- toxins
Give examples of agents that cause embolic pneumonia. (4)
septic emboli
- endocarditis
- injection site abscess
- hepatic abscess with phlebitis of hepatic vein (cattle)
- infected jugular catheters
Give examples of agents that cause granulomatous pneumonia. (4)
- fungal organisms (Blastomyces dermatitidis)
- some bacteria (Mycobacterium sp.)
- aberrant parasites (ascarid larva)
- foreign bodies
What are four categories used to describe the morphology of a lung lesion?
duration
distribution
degree of severity
exudate
Why does bronchopneumonia of cattle and swine resolve more slowly than that of other domestic animals?
cattle and swine do not have collateral ventilation of alveoli, thus they have reduced clearance of exudates
A calf has bronchopneumonia. In terms of pathogenesis, list at least three possible resolutions or outcomes of the bronchopneumonia.
- Death - toxemia developed
- Complete resolution - infection removed by immune response or antibiotics
- Chronic suppurative bronchopneumonia - persistent infection or secondary bacterial infection
What is the pathophysiological significance of bronchopneumonia? (4)
- loss of functional parenchyma for ventilation
- decreased elasticity/compliance of lung
- progress to death, pulmonary fibrosis, septicemia, bronchiectasis
- chronic bronchopneumonia results in weight loss and progressive loss of lung function
What is a lung sequestrum and how long does it persist in the lung?
mass of necrotic tissue that is separated from normal lung by suppurative exudate and fibrous connective tissue
permanent and nonfunctional
