Respiratory System, Pt. 2 Flashcards
What are the 5 most common patterns of pneumonia?
- suppurative bronchopneumonia (CRANIOVENTRAL - bacteria)
- fibrinous bronchopneumonia (CRANIOVENTRAL - liver consistency)
- interstitial pneumonia (rib impressions - viruses)
- embolic pneumonia (firm nodules, multifocal, hemorrhagic)
- granulomatous pneumonia (pale firm nodules - Mycobacteria)
How does the route of infection cause differences in presentation of pneumonia?
AEROGENOUS = concentrations at bronchi
HEMATOGENOUS = random scattered nodules
Pneumonia patterns:
What causes infectious bovine rhinotracheitis (IBR)?
BoHV-1
How do parainfluenza virus 3 and bovine respiratory syncytial virus affect the lungs? How do they affect calves?
cause transient rhinotracheitis and bronchointerstitial pneumonia with the formation of eosinophilic intracytoplasmic inclusion bodies in bronchial, bronchiolar, and alveolar epithelial cells, and aleolar macrophages + syncytial cells
necrotizing bronchiolitis
How is parainfluenza virus 3 and bovine respiratory syncytial virus infection confirmed?
- PCR
- detection of viral antigens by FAT or IHC
BRSV, cow:
- diffuse, interstitial (hard to recognize)
- no clear areas of consolidation
- large, rubbery, rib impressions
BRSV, calf and heifer histology:
- bronchiole with necrotic debris in lumen
- increased cellularity, syncytial cells, pink IC inclusions
BRSV, histology:
- virus damages interstitium and bronchioles
- syncytial cells have the same cytoplasm, with multiple nuclei
BRSV, IHC histology:
widespread injury to the airway epithelium
What 2 respiratory viruses cause bovine enzootic pneumonia? Opportunistic bacteria? How does it present?
Mycoplasmas and Chlamydophila
- Pasteurella multocida
- Trueperella pyogenes
- Histophilus somni
- Mannheimia haemolytica
CRANIOVENTRAL chronic suppurative bronchopneumonia
Chronic suppurative bronchopneumonia, calf:
- bovine enzootic pneumonia
- cranioventral consolidation and discoloration
What calves are highly susceptible to bronchopneumonia?
those with bovine leukocyte adhesion deficiency (BLAD), which prevents the migration of neutrophils from the capillaries
Bovine enzootic pneumonia, calf:
- consolidated
- chronic suppurative bronchopneumonia
Suppurative pneumonia, calf:
- enzootic bronchopneumonia
- increased neutrophils in the lumen
What are 2 common sequels of chronic suppurative pneumonia?
- cranioventral abscessation
- bronchiectasis
Bronchiectasis:
common sequel to chronic suppurative pneumonia, where the bronchioles are full of exudate and dilate with the destruction of septa and replacement by connective tissue
What is shipping fever? What is the main etiology? How does it present?
acute respiratory disease that occurs in cattle several days or weeks after shipment or other stressful events —> most economically important respiratory disease of cattle in North America, especially feedlot cattle
Mannheimia haemolytica - pneumonic mannheimiosis/pasteurellosis
CRANIOVENTRAL fibrinous bronchopneumonia with fibrin attachment to pleura
Pneumonic mannheimiosis, steer:
- shipping fever
- Mannheimia haemolytica
- locally extensive consolidation and yellow discoloration
- fibrinous, necrotizing
What is the characteristic internal lesion of shipping fever? What is responsible for this lesion?
marbling appearance of pulmonary parenchyma - inflammation + necrosis + edema
Mannheimia haemolytica, biotype A, serotype 1 toxin causes vasculitis and necrosis
What kind of necrosis does Mannheimia haemolytica cause in shipping fever?
coagulative —> missing cellular detail, but organ structure remains
What is the etiology of respiratory histophilosis? What else can it cause?
Histophilus somni
- TME
- pneumonia
- pleuritis
- myocarditis
- arthritis
- abortion
How does respiratory histophilosis present grossly? What does it tend to look like? How can it be differentiated?
CRANIOVENTRAL suppurative or fibrinous bronchopneumonia
Mannheimia haemolytica infection (shipping fever) - histophilosis will have no marbling necrosis upon sectioning
How does Mycoplasma bovis pneumonia present grossly? What else does it commonly cause?
chronic necrotizing bronchopneumonia with cranioventral consolidation and nodular, confluent, multifocal to coalescing lesions
fibrinous arthritis
Mycoplasma bovis, pneumonia:
- CRANIOVENTRAL
- chronic necrotizing pneumonia
- nodular, look like abscesses
- doesn’t respond to normal therapy
- feedlot cattle!
Necrotizing bronchopneumonia, heifer:
- Mycoplasma bovis
- solid lesions that look like abscesses (not suppurative)
What kind of necrosis does Mycoplasma bovis cause?
caseous —> cannot recognize tissue at all
What causes bovine tuberculosis? What tends to cause outbreaks in North America?
Mycobacterium bovis
wildlife, like deer, elk, and bison (ruminants), are able to carry disease and come into contact with cows on the farm
How does gross presentation of bovine tuberculosis compare in cattle and wild cervids?
multifocal granulomatous pneumonia, including involvement of retropharyngeal, thoracic, and mesenteric LN
contain prominent suppurative exudate and may resemble abscesses
What is a common cause of verminous bronchitis/pneumonia in cattle? What are the 3 general gross presentations? What is the most common morphological diagnosis used?
Dictyocaulus viviparus
- larval migration = interstitial pneumonia
- intrabronchial adults = interstitial pneumonia
- eggs, dead larvae = granulomatous pneumonia
catarrhal (mucosuppurative) bronchitis
What are the common causes of verminous bronchitis/pneumonia in sheep/goats and equids?
SHEEP/GOATS = Dictyocaulus filaria
EQUIDS = Dictyocaulus arnfieldi
What is the most common cause of verminous bronchitis/pneumonia in pigs? How does it present grossly?
Metatrongylus spp.
lungworms admixed within turbid mucoid exudate - catarrhal bronchitis
Verminous bronchitis, pig:
- numerous thin and elongated worms = Metastrongylus spp.
- present in caudal (diaphragmatic) lung lobes
- catarrhal bronchitis
- pallor = pneumonia
Parasitic bronchitis, pig:
- Metastrongylus spp. in bronchus
- CAUDAL lung lobe
- catarrhal bronchitis
- verminous bronchitis
What are the 5 characteristics of atypical interstitial pneumonia (AIP) in cattle?
- edema
- interstitial emphysema
- hyaline membranes
- type II pneumocyte hyperplasia (replace type I pneumocytes upon injury and cause hepatization of lung)
- interstitial fibrosis with cellular infiltrates
Atypical interstitial pnuemonia, cow:
- diffuse alveolar damage with protein leakage mixing with surfactant and lipids causes the formation of eosinophilic hyaline membranes lining alveoli
- increased cellularity
What are 4 common syndromes considered atypical interstitial pneumonia?
- bovine pulmonary edema and emphysema (fog fever)
- extrinsic allergy alveolitis (hypersensitivity)
- reinfection syndrome - hypersensitivity to Dictyocaulus spp. or BRSV
- milk allergy - type I hypersensitivity in cows sensitized to their own milk casein and lactalbumin
How does the ingestion of moldy potatoes cause interstitial pneumonia?
contains 4-ipomeanol, which is metabolized by mixed function oxidases in the lung (club cells) to a potent pneumotoxicant
How does fog fever present grossly? In what cattle is it most commonly seen?
bovine interstitial pulmonary edema and emphysema —> may rupture and cause fatal pneumothorax
cattle grazing “fog” pastures - regrowth pasture after hay or silage has been cut or lush green grass
What is the pathogenesis of fog fever?
- L-tryptophan present in the pasture is metabolized in the rumen into 3-methylindole
- 3-methylindole is absorbed into the blood and carried into the lungs
- 3-methylindole is further metabolized by mixed oxidases, Club cells, into a highly pneumotoxic compound that causes extensive necrosis of bronchiolar epithelial cells and type I pneumocytes (diffuse alveolar damage
When is extrinsic allergy alveolitis (hypersensitivity pneumonitis) commonly seen? What is the human counterpart? What kind of reaction is this?
adult dairy cows in the winter
farmer’s lungs
type III hypersensitivity reaction to inhaled organic antigens, most commonly fungal spores in moldy hay resulting in the deposition of Ag-Ab complexes into the lungs
What are the main 2 gross lesions seen in extrinsic allergic alveolitis (hypersensitivity pneumonitis)?
- gray subpleural foci of granulomatous inflammation
- “meaty” lung appearance due to alveolar epithelial hyperplasia, interstitial inflammation, and fibrosis
Pathogenesis of toxic and allergic pneumonias (AIP) in cattle:
What is Maedi (maedi-visna)? What causes this?
lifelong, persistent disease of sheep that occur in most countries (except Australia and New Zealand) known as ovine progressive pneumonia (OPP)
retrovirus of the (ovine) lentivirus subfamily, similar to the agent of CAE
How does Maedi (maedi-visna) present grossly? What signs are characteristic? What causes similar lesions in goats?
lymphocytic interstitial pneumonia with non-suppurative encephalitis, lymphocytic arthritis, and lymphofollicular mastitis/vasculitis
dyspnea and an insidious slowly progressive emaciation despite good appetite
CAE virus
What sheep are most affected by chronic enzootic pneumonia? What are the 8 possible etiologic agents?
those younger than 1 year old
- Mannheimia haemolytica
- Pasteurella multocida
- PI-3
- adenovirus
- reovirus
- RSV
- Chlamydophila spp.
- Mycoplasma ovipneumoniae
(first viral injury, survival, develop enzootic pneumonia)
How does ovine chronic enzootic pneumonia present grossly?
CRANIOVENTRAL suppurative bronchopneumonia
Ovine pneumonic mannheimosis is very similar to shipping fever in cattle. What is seen in sheep that sets it apart? What are the main 2 etiologic agents?
septicemic pasteurellosis
- Mannheimia haemolytica (biotype A) - lambs under 3 months
- Bibersteinia trehalosi (biotype T) - lambs 5-12 months old
What are the main 3 lesions associated with septicemic pasterellosis seen in ovine pneumonic mannheimosis?
- necrotizing pharyngitis and tonsilitis
- septicemia with disseminated intravascular thrombosis
- bacteremia
What are the common causes of verminous pneumonitis and bronchitis in goats and sheep? How does it appear grossly?
- Muellerius cappilaris
- Dictyocaulus filaria
verminous foci of consolidation and discoloration of CAUDAL portions of CAUDAL lung lobes with eosinophilic and granulomatous inflammation
What are the 3 most common causes of viral pneumonia in horses?
- equine viral rhinopneumonitis (EHV-1, EHV-4)
- equine influenza
- equine viral arteritis
How does viral pneumonia affect horses?
typically only cause transient bronchointerstitial pneumonia, but can impair pulmonary defenses, leaving the horse susceptible to
- bacterial pneumonia: P. multocida, Streptoccocus spp., E. coli, Klebsiella pneumoniae, Rhodococcus equi)
- airway hyperresponsiveness and RAO (chronic bronchiolitis-emphysema complex, heaves)
Interstitial pneumonia, foal:
- VIRUS
- rib impression
- diffusely enlarged (takes up most of thoracic cavity)
- darker
- rubbery, increased consistency
+ cranioventral consolidation of bronchopneumonitis
What is SCID? What animals are commonly affected by this? What is a common sequel in these animals?
inherited disorder characterized by a lack of B and T lymphocytes, typically causing death by 5 months (colostrum gives protection)
Arabian horses and Jack Russel terriers
interstitial pneumonia due to adenovirus or Pneumocystis carinii
What is characteristic of pneumocystosis in pigs? What is it a common sequel to?
foamy eosinophilic proteinaceous material within alveoli with fungal organisms detected (typically with GMS)
previous infection by PRRSV
Adenovirus infection, foal:
- intranuclear inclusion bodies
- typically secondary to SCID
What infection is commonly concomitant with Pneumocystic carinii infection secondary to SCID in Arabian foals? How does it present grossly?
Rhodococcus equi
- enlarges and edematous lungs
- pinpoint lesions = foci of necrosis and pryogranulomatous inflammation
What is Rhodococcus equi? What 2 syndromes is it typically responsible for?
facultative Gram-positive bacterium that causes major infection in foals (that can act as shedders)
- enterocolitis/lymphadenitis
- pyogranulomatous pneumonia
What makes Rhodococcus equi infection difficult to treat? How does it typically present grossly?
virulence factors encoded by plasmids allow for the survival of the bacterium within macrophages and avoid phagocytosis by inducing defective phagosome-lysosome fusion
chronic pyogranulomatous pneumonia —> solid lesions that resemble abscesses
When are foals typically suspected of having Rhodococcus equi bronchopneumonia? What causes the extensive caseous necrosis?
presenting bronchopnuemonia is unresposive to routine broad-spectrum antibiotic therapy
cytokines, lysosomal enzymes, bacterial toxins, recruitment of neutrophils, macrophages and giant cells —> affected foals will exhibit chronic coughing with weight loss
Is Rhodococcus equi zoonotic? How does the other syndrome it causes typically present grossly?
YES - can infect people undergoing immunosuppression (AIDS, chemotherapy, therapeutically-induced immunosuppression, etc.)
pyogranulomatous enterocolitis and lymphadenitis due to coughing up up bacterial organisms and swallowing
What is a typical cause of embolic pneumonia in horses? What is it commonly a complication of? How does it look grossly?
Aspergillus
Salmonellosis - fungi reach portal and systemic circulation and reach lungs, forming an embolus
multifocal, necrohemorrhagic pneumonia - raised red foci with central pallor of necrosis
What are the 4 main viral pneumonias of pigs?
- PRRS: late-term abortions, stillbirths, respiratory disease in young pigs
- swine influenza: adaptation of type A influenza virus (H1N1)
- postweaning multisystemic wasting syndrome: PCV-2 causes pneumonia and emaciation in weaned pigs
- porcine respiratory coronavirus: mild pneumonia with necrotizing bronchiolitis
BRONCHOINTERSTITIAL pneumonia
Interstitial pneumonia, feeder pig:
- VIRAL
- rib impressions
- uncollapsed, large
- increased consistency (increased cellularity of septa)
What is the most common cause of Pneumocystosis in pigs?
primary PRRS or PMWS leaves pigs immunocompromised and susceptible to fungal infections
What causes porcine enzootic pneumonia? What does it cause? What affects development of disease
Mycoplasma hyopneumoniae
induces CRANIOVENTRAL suppurative or catarrhal bronchopneumonia with BALT hyperplasia
immune status and management factors, such as crowding, poor ventilation, humidity, and temperature fluctuations
What is the classical appearance of porcine enzootic pneumonia?
fish flesh appearance —> salmon
- CRANIOVENTRAL discoloration and consolidation
- Mycoplasma hyopneumoniae
- suppurative, catarrhal
What is the severity of porcine enzootic pneumonia? What makes infection worse?
mild to moderate with low mortality
complication with Pasteurella multocida, Tureperella pyogenes, Bordetella bronchiseptica, Haemophilus spp., or Mycoplasma hyorhinis infection
What causes polyserositis? How does it present grossly?
Haemophilus parasuis —> Glasser’s disease
young, suckling pigs with fibrinous accumulation on pleural and peritoneal cavities and consolidated parenchyma
Fibrinous pleuritis and pneumonia, 3-month-old pig:
- Glasser’s disease —> polyserositis
- Haemophilus parasuis
- involvement of visceral and parietal pleura
What causes porcine contagious pleuropneumonia? How does it present grossly?
Actinobacillus pleuropneumoniae
fibrinous, hemorrhagic, and thrombotic bronchopneumonia of 2-5 months-old pigs with no involvement of the cranial lung lobes
Porcine contagious pleuropneumonia:
- Actinobacillus pleuropneumoniae
- middle or caudal lung lobes, NO cranial lobe involvement
Porcine contagious pleuropneumonia, cut surface:
- Actinobacillus pleuropneumoniae
- marble appearance with hemorrhage and necrosis
What are the 2 types of pneumonias in dogs?
- infectious - tracheobronchitis (Kennel cough), Bordetella bronchiseptica, canine distemper, canine adenovirus-2, CHV-1, canine influenza
- non-infectious - uremia and paraquat toxicity
What are the main causes of bacterial pneumonias in dogs?
secondary to distemper virus infection or aspiration of gastric contents
- Pasteurella multocida
- Streptococcus spp.
- E. coli
- Klebsiella pneumoniae
- Bordetella bronchiseptica
Bronchointerstitial pneumonia, dog:
- VIRUS: canine distemper
- increased size and consistency
- cranial congestion
- IC and IN inclusion bodies
How does aspiration pneumonia typically present grossly? What are 2 common causes?
unilateral (right) CRANIOVENTRAL consolidation and necrosis
- improperly placed nasogastric tube
- aspiration of gastric contents (fast before surgery!)
How does Blastomyces dermatitidis pneumonia present grossly? Where is this infection most common?
granulomatous pneumonia - multifocal nodules
souther states - inhaled or hematogenous spread
Mycotic pneumonia, dog:
- granulomatous pneumonia
- Blastomycosis
- Histoplasmosis
What causes uremic pneumonopathy? How does it present grossly?
renal failure cause profuse pulmonary edema and mineralization of septal alveoli basement membrane
- diffuse interstitial pneumonia
- rib impressions
- large and uncollapsed
What respiratory infections are most common in cats?
upper respiratory infections
- pneumonias tend to be rare
What is the most common cause of verminous pneumonia in cats? How does it look grossly?
Aeurostrongylus abstrusus
multifocal, raised, tan, subpleural granulomatous nodules (catarrhal) —> caudal lung lobes
What are the intermediate hosts of Aeurostrongylus abstrusus? What do the subpleural nodules contain?
snails and slugs
larvae and eggs
What are the most common pulmonary neoplasias in animals?
dogs and cats —> secondary metastatic malignant tumors
- large nodules with smaller ones surrounding it = intrapulmonary metastasis
Pulmonary adenocarcinoma, cat:
neoplastic proliferation of epithelium forming glandular tubules
What is the most common primary pulmonary tumor in sheep? How does it present grossly?
ovine pulmonary carcinoma (adenomatosis) caused by a transmissible retrovirus with slowly progressive signs of respiratory disease and death
looks inflammatory, like bronchopneumonia
Metastatic pulmonary tumors are most common. At what age are most primary neoplasms seen in dogs and cats?
older aged
- multifocal, raised, cystic, hemorrhagic
- metastatic hemangiosarcoma
Metastatic pulmonary neoplasm:
- multifocal, tan, raised nodules
- enlarged thyroid = metastasis
Pulmonary melanoma, dog:
metastasis from oral cavity
What is a common cause of hydrothorax? How does it affect the lungs?
chronic liver disease (cirrhosis) = decreased albumin, hypoproteinemia
compressive atelectasis —> patchy
What is a common cause of hemothorax? What does this cause?
severe trauma - HBC, ruptured aortic aneurisms
- hypovolemic shock
- compressive pulmonary atelectasis (patchy)
What is a common cause of chylothorax? How does this affect the lungs?
rupture of lymphatic ducts with leakage of lymphatic fluid
compressive atelectasis
What commonly causes fibrinous pleuritis in horses?
Streptococcus equi subsp. zooepidemicus - shipping fever
Fibrinous pleuritis, horse, histology:
- shipping fever caused by Streptococcus equi subsp. zooepidemicus
- neutrophil accumulation limited to pleural surface
- lungs not affected
How does pyothorax typically present grossly? What is a common cause in cats?
suppurative, brown exudate accumulation in the thorax, compressing the lungs —> atelectasis
abscesses form from Pasteurella multocida infection and eventually burst
What is the etiological agent chronic pleuritis with sulfur granules?
Nocardia asteroides, typically secondary to bite wounds
In what animals are mesotheliomas most common? What causes its development in humans?
cattle - can be congenital —> looks like pleuritis
inhalation of asbestos from mining, construction, or shipbuilding
