resp 3 lectures Flashcards
bronchopneumonia in dogs
- possible presentations
- more diverse presentations than in other species > palapte!
a) cranioventral
b) diffusely reddened, lobar consolidation
c) lobar consolidation
Predisposing causes for bronchopneumonia in dogs
- Aspiration pneumonia (eg. anesthesia, megaesophagus, laryngeal paralysis, vomiting…)
- Contagious bacteria: Bordetella
- Predisposing viral infections
- Neutropenia > eg. parvo, immunosuppressive drugs
- Immunosuppression: therapy, chilling, stress, genetics
- Ciliary dyskinesia (rare)
Canine distemper:
1. What is the causative agent?
2. What 3-5 body systems are most commonly affected?
3. How common is the virus & the disease in Ontario?
- canine distermper virus
- affects resp disease, also neurological, skin (crusted footpads), lymphoid tissue > immunosuppression and secondary infections, enamel hyperplasia
- not common in Ontario > well vaccinated
the nature of lung tumors in dogs - usually metastatic or what?
a large diversity, can be hard to tell
Pulmonary Thromboembolism
* Are pulmonary thromboemboli easy to detect postmortem?
* How to distinguish in situ thrombus vs pulmonary embolus?
* 2 sources of emboli (in any species)?
* 3 predisposing causes for in situ thrombosis?
- where to look for source of embolus?
- need to open up pulmonary artery!
- in situ are generally microscopic, within venules in the lung, grossly visible is usually embolus (95% of the time)
> think of hypercoaguable states, glomerular disease with loss of antithrombin, spesis, corticosteroid therapy, pulmonary vascular disease eg. heartworm… all can predispose to thrombosis
<><><><><> - Hypercoagulable state: glomerular disease, IMHA, cancer, glucocorticoids, heartworm, sepsis
- Local trauma/inflammation
- Sluggish blood flow
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where to look for embolus source? - look at right heart valves for endocarditis
- jugular for thrombus
- liver - for liver abscesses (esp feedlot calves)
Eosinophilic lung diseases in dogs
- how common? treatment?
not common - but identification good as they respond well to corticosteroid therapy
blastomycosis
- cause
- lesions
- ddx
- hyphae are found in the soil - infectious to animals and humans > inhalation from environment
> generally does not spread from one species to another
> (can innoculate yeast form if you cut yourself during PM) - Infection begins in the lung, and may spread to skin, eye, bone, and/or other viscera. (uveitis, osteomyelitis)
- Infection induces granulomatous inflammation, forming multiple soft white nodules.
- In older dogs, metastatic neoplasia is a more likely differential diagnosis
pleuritis in dogs - who? cause, presentation, causes and pathogens
- large breed dogs
- penetrating injury
- smoldering, slow growing infections usually
- actinomyces, nocardia
> migrating pieces of grass awn/ tufts that make their way into the skin and migrate further into tissues
Respiratory viruses of cattle
- bovine resp syncytial virus
- parainfluenza virus
- IBR
- bovine coronavirus
- BVDV?
In cranioventral lung, the alveoli are collapsed and contain very little air.
* What is this called?
* What are the three general causes of this lesion, and why did it develop in this case?
Atelectasis
– airway obstruction (eg by exudates, as in this case), external pressure (pneumothorax, pleural effusion), fetal atelectasis
There are air-filled spaces in the interlobular septa.
* What is this called?
* What are general causes of this lesion, and why did it develop in this case?
- Interlobular emphysema
> pressures in lung rupture alveoli - Distinguish: interlobular emphysema (2ry to respiratory distress) vs alveolar emphysema (rare in animals) vs air trapping (partial bronchiolar obstruction)
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interlobular emphysema - seen in resp distress in horses cattle pigs > can be incidental finding in cows… if you see this lesin in a cow but feels normal on palpation, look elsewhere for cause of death
alveolar emphysema - destruction of alveolar septa from proteases… not common in domestic animals
BSRV - group of bovines with resp disease, how do you go about making a diagnosis (if they didnt die) (viral)?
sample - PCR
- nasal swabs from multiple animals
- could also do transtracheal wash, bronchoalveolar lavage… but generally pathogen present in nasal cavity which will be easier
- take blood and determine exposure via serology / antibodies (look for a rise over time)
- Foci with friable crumbly dry material. Which type of necrosis?
- What species of Mycoplasma causes this lesion in cattle?
- Characteristic clinical appearance?
- bronchopneumonia with white pale nodules
> caseous necrosis - mycoplasma bovis
- can also get inner ear infections, joint disease, mastitis
> either up auditory tube to the ear, or down trachea to lungs…
Bovine -
How to distinguish tracheal ulceration +exudate from expectorated mucus? on PM
- cause?
- possible reasons for death
- if coughed up from the lung, can run your finger across it and it will come off > reveal smooth, shiny mucosa underneath
- IBR-1: causes ulceration, material is firmly adherent and cannot be scraped away without scraping off the mucosa itself
- calves may die if they aspirate this material and asphyxiate on it
- more commonly, die due to secondary bacterial pneumonia > inflammation, suppression of macrophage responses from this virus
- ubiquitous virus in feedlot cattle even if the disease is not frequently seen
checkerboard pattern in lung - what type of lung disease?
- what will we often see with this?
- cause in cattle?
- generally interstitial
- will be relatively uniform across the lung
- will see interlobular emphysema and interlobular edema
> firmer than normal - no one really knows what the cause is… high energy rations? can be related to tryptophan from lush forages in pastured cattle > 3-methyl endol toxicity
acute fibrinous pleuritis in feedlot calf, 30 days, found dead.
lung tissue is reddened, but of normal texture
likely cause?
- other lesions assoc. with this pathogen?
- significance
- histophilus somni most commonly
(Mannheimia haemolytica or E. coli septicemia could be ok guesses, but would more commonly affect lung) - characteristically spares lung tissue
- Other lesions: brain disease, thromboembolic menigoencephalitis, arthritis, abscess in myocardium / infarct (papillary muscle of left ventricle)
- more common cause of mortality in beef feedlots
bacterial showering of the lung - when will it lead to interstitial vs embolic pattern
interstitial - a lot of bacteria very fast
embolic - slower, over longer time
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- systemic bacterial infection can cause either
DICTYOCAULUS VIVIPARUS
- parasite appearance, where found
- who gets this?
- lesions
cattle lungworm
- Adults worms are grossly visible, thread-like, white nematodes in bronchi within caudal lobes
- pastured cattle
- lesions in caudal lung
> calf aspirates eggs and larvae, results in caudal lube areas of inflammation
granuloma in cattle lung - important cause we should consider? lesion? significance?
- lesion in deer/ elk?
- mycobacerium bovis
- look in lymph nodes > more commonly found there than lung!
- caseous necrotic center, granulomatous inflammation
- lesions can erode through pleura, or spread through blood…. cause miliary lesions in lung or other tissues
- reportable!
- look more like abscesses in deer - consider it
- bronchopneumonia (CV distribution) in cattle, what pathogens to consider?
- what tells us if it is acute?
- mannhemia haemolyitca
- histophilus somni
- pasteurella mulocida
<><><><> - acute case will be evident by:
> loosely adherent fibrin on surface, very dark hemorrhagic areas of lung
Horse:
Ventral surface of skull.
Red arrow= pus in the retropharyngeal lymph node.
* Name the disease & the cause?
* Three fatal sequelae to this disease?
- strangles > strep equi equi
- rare in ontario, but can happen
- very contagious bacterium
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Sequelae: - aspiration pneumonia > pus in upper resp tract, inhaled into lungs > bronchopneumonia, lung abscesses from bacterial laden pus
- bastard strangles > strep equi travel through blood from primary site to lymph nodes elsewhere in the body, form abscesses > can occur anywhere in body
> often in mesentery - purpura hemorrhagica > immune complex mediated (type 3 hypersensitivity) > bacteria remains localized in retropharyngeal LNs > antibody-antigen complexes spread through blood, deposit in vessel walls > vasculitis throughout body
> edema of forelimbs, petechial hemorrhages of gums, skeletal muscle, etc.
guttural pouch
* 3 diseases affecting this structure?
* 2 sequelae to guttural pouch mycosis?
- mycosis > fungal hyphae like to run along blood vessels, can invade carotid > massive hemorrhage into guttural pouch
- tympnay > air trapped in pouch, non-fatal
- empyema - pus within the cavity, filled > due to streptococcus or other bacteria
<><><><> - have significant structures adjacent > cranial nerves and carotid arteries
- guttural pouch disease:
> cranial nerve deficits
> fungal erosion of carotid, can be fatal
1.What disease causes bronchiolar inflammation in adult horses?
2.Why are the airways obstructed?
- alveoli normal, inflammation surrounding bronchioles, exudate within lumen of bronchiol
> heaves = severe equine asthma (inflammatory airway disease
<><><>< - exudate in lumen
- inflammation of bronchiolar wall
- hyperreactivity of airway smooth muscle > bronchoconstriction
Exudate in pleural cavity, draining out. Lots of fibrin on PM…. (fibrinous pleuritis)
Of these 4 plausible routes of bacterial infection of pleura, which is most likely in a horse?
a. Hematogenous
b. From lung
c. Penetrating injury
d. Esophageal perforation
- most horses with fibrinous pleuritis, fluid in chest cavity
> usually extension from underlying pneumonia
> horses who have been transported with heads elevated > pooling of fluids at thoracic inlet > aspirated, aspiration pneumonia > small lung lesion can extend through pleural tissue into pleural cavity
<><><><> - therefore, from lung!
RHODOCOCCUS EQUI
- lung pattern?
- disease progression?
- who is affected?
- other possible manifestations?
- cranioventral pattern of consolidation, and these consolidated lesions contain multifocal pyogranulomas that develop into abscesses
- always a chronic disease, even if the clinical presentation is acute
<><><><> - facultative intracellular pathogen that survives within macrophages
- 2-6-month- old foal
- infection and the lesions are always chronic, but clinical signs may be either acute or chronic
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can also cause: - diarrhea (colonic form) > if ingested from soil rather than inhaled (taken up by colonic lymph nodes)
> may also be coughed up and swallowed - polyarthritis
foal:
* The lung is diffusely firm, with a firm rubbery texture throughout.
* What pattern of lung disease is represented? - disease in foals???
* What is the likely cause of the nodular firmer lesions ?
- interstitial pneumonia, acutely fatal, nobody knows the cause in juvenile foals
<><><> - nodules are rhodococcus
Interstitial pneumonias in neonatal foals
- possible causes, that we see with some frequency??
- Sepsis (acute diffuse lesions, vs. subacute embolic pneumonia)
- Equine herpesvirus: diffuse (broncho)interstitial pneumonia
- Hyaline membrane disease
> Failure of surfactant production in premature foals
> Results in increased alveolar surface tension, atelectasis, and injury to type I pneumocytes from high intra-alveolar pressures
