Respiratory: Lung Disease Flashcards
How would a hypostatically congested lung appear grossly?
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)
What is the number one cause of congestion & edema in the lungs? Name a couple others too.
- Left-sided heart failure (cardiogenic edema): increased capillary hydrostatic pressure
- Excessive fluid transfusion
- Brain injury: systemic vasoconstriction (neurogenic edema)
What are the causes of congestion and edema in the lungs?
- Decreased hydrostatic blood pressure
- Increased permeability
- Decreased plasma onctotic pressure
- Lymphatic obstruction – everyone forgets this one
Name a cause of increased permeability and subsequent congestion and edema of the lungs.
Epithelial injury:
- Toxic Gases
- Toxic plants (moldy sweet potatoes, purple mint)
- 100% oxygen
- Virus infection
Endothelial injury:
- gram negative septicemia (endotoxins)
Name a cause of decreased plasma oncotic pressure and subsequent edema and congestion of the lungs.
- Hypoalbuminemia and hypoproteinemia as a result of nephrotic syndrome
Anything that causes inflammation of the kidney or impairs liver function.
Name a cause of lymphatic obstruction and subsequent edema and congestion of the lungs.
- Metastatic malignant melanoma
- Lymphoma
- Metatstatic hemangiosarcoma (Dog)
- Neoplastic invasion or compression of lymphatics
What signalment is most prone to Strangles?
Young Horses (1-5 years)
Anorexia, fever, mucopurulent nasal discharge
What pre-disposes a horse to Strangles infection?
- Recent group of large horses (show, sales barn, race, etc.)
- Prior Strangles outbreak on the farm
Pathogenesis of Strangles
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
What is the causative agent of Kennel Cough in canines?
Bordatella bronchiseptica
What are the lesions assocaited with Kennel Cough?
- Coughing exacerbated by exercise
- Suppurative tracheobronchitis/bronchiolitis
- +/- 2˚ pneumonia (E. coli, Pseudomonas, Kelbsiella)
Define: thrombosis
An irregular clot forming
Define thromboembolism:
thrombus forms somewhere and travels elsewhere
Whats more common in the lungs: thrombus or embolism?
embolism
What would cause a thrombus in the lungs?
Thrombus 2˚ to:
- parasites
- hypercoagulation disorders
- endothelial damage
What is a consequence of pulmonary thrombi or emboli?
Lung infarcts:
- Dual blood supply reduces incidence
- pre-existing lung disease increases incidence
Describe the lesion associated with lung infarct.
Firm, deep red, edges of lung lobe, +/- fibrin
What are the abnormalities of inflation?
Atalectasis and Emphysema
Describe lesions associated with atalectasis.
too little air in the lung:
firm, dark red, usually edges of lung lobe
Describe lesion associated with emphysema.
crepitus - “bubble wrap” feeling
What is the most common cause atalectasis?
Obstruction: collapse of all the airways distal to the obstruction and consequential resorption of air leads to collapse.
What are causes of atalectasis?
Congenital:
- Fetal - affects entirety of lung
Acquired:
- Obstructive
- most common form
- Compressive
- Hypostatic
Describe cuases of Congenital Atalectasis.
- 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
- Dystocia
Describe lesiosn associated with congenital atalectasis.
Deep dark red, but fleshy since never took a breath, therefore never collapsed
Describe obstructive atalectasis.
-
Inflammatory exudate obstructing bronchioles
- most common
- Parasites
- Neoplastics cells
- start in lumen and obstruct or adjacent to airways and compress
Describe lesions of obstructive atalectasis.
Histologic:
- Inflammation with nø in bronchioles
Gross:
- Atalectatic lobules depressed
Describe compression atalectasis.
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
In what species does compression atalectasis happen most commonly? Why?
Lobulated lung species: Ruminants and Pigs and to a lesser extent horses
Why? –> They lack good collateral ventilation. (absence of pores between air spaces)
Describe GROSS appearance of atalectasis.
- 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
Describe MICROSCOPIC appearance of atalectasis.
- Collapse of alveolar space resulting in alveolar septae being in close appostion without fluid or cells in collapsed spaces.
Define emphysema of the lung. What types are there?
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
What type of emphysema is more prevalent in veterinary medicine?
Interstitial emphysema
Cattle (most common), pigs, goats
What does alveolar emphysema mean in veterinary medicine?
the ante mortem over distension of air spaces distal to terminal bronchioles
What species is most prone to Interstitial emphysema?
Cattle, then sheep and pigs
Can interstitial emphysema and lobular atalectasis occur at the same time?
Yes, in cattle, sheep, and pigs
Define bronchopneumonia.
inflammatory exudate primarily located in bronchi, bronchioles and alveolar spaces
- Suppurative vs Fibrinous
Define interstitial pneumonia.
Inflammatory exudate primarily located in the lung intersitium (alveolar septae).
Air spaces relatively free of exudate.
- Acute vs. Chronic
Define pneumonia.
Any inflammatory lesion in the lungs (Veterinary Medicine)
Define granulomatous pneumonia.
Chronic pneumonia characteristically composed of epitheliod MØ and/or multi-nucleate giant cells plus other inflammatory cells
What organism(s) can cause suppurative bronchopneumonia?
- Pasteurella mutocida
- Mycoplasma spp
- E. coli
- other G - bacteria
What organisms can cause fibrinous bronchopneumonia?
- Manheima hemolytica (cattle)
- A. pleuopneumonia (pigs)
- Pasteurella multocida (chicken)
-
E. coli
- chickens
- dogs (toxigenic strains)
What are the gross features of suppurative bronchopneumonia?
Lobular involvement varies:
- sharp line of demarcation
- checkerboard appearance on cut surface
- some atalectatic, some obstructed, some suppurative/inflamed
What are gross features of fibrinous bronchopneumonia?
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
