L27: Pt.3 Flashcards
Vena caval thrombosis
- most common in feedlot cattle
- CS: wt. loss, resp. Signs with anemia, wheezes, hemoptysis**
- rapid deterioration after hemoptysis
- Tx: penicillin, NaCl
- almost always fatal
- 2ary to rumen acidosis
Pathogenesis of vena caval thrombosis***
rumen acidosis, rotting grain in the rumen –> rumenitis –> Fusobacterium and Trueperella infections in the wall of the rumen –> transported via portal system to the liver –> liver abscesses –> abscesses impact the caudal vena cava –> caudal vena cava thrombosis –> pieces of septic thrombi break off, pass through the thrombus, and into the right heart –> septic pulmonary emboli –> pulmonary abscesses and aneurysms –> rupture into airways and bleed out via mouth and nose
Types of interstitial pneumonia
- Atypical interstitial pneumonia (aka ARDS)
- Hypersensitivity diseases
- chronic interstitial pneumonia
- parasitic pneumonias
Causes of Atypical interstitial pneumonia
- pasture-assoc.
- feedlot AIP
- moldy sweet potato toxicity
- Perilla ketone toxicity
- poison gases and fumes
Most common cause of respiratory dz after 30 days on a feedlot***
Atypical interstitial pneumonia (AIP)
-unknown cause
Pathologic findings of AIP
- lungs fail to collapse
- firm rubbery with interlobular or bullous emphysema
- affected lobules interspersed with normal
Histopath:
-Alveolar hyaline membrane formation and fibrin deposition
-edema
Type 2 pneumocyte proliferation
-hemorrhage, emphysema, interstitial inflammatory infiltrate
Acute Bovine Pulmonary Edema and Emphysema - ABPEE (“Fog Fever”)
-AIP in adult cattle >2 yrs
-occurs when transition to lush green pasture
-acute onset resp. Signs
-coughing rare
+/- emphysema
Metastatic pneumonia
- comes from septic emboli from jugular vein phlebitis, mastitis, metritis, footrot
- common agents: Fusobacterium, Trueperella, E. Coli, Staph, Strep
Tx/Prevent of ABPEE
Tx: avoid stress; flunixin, steroids, diuretics
Prevent: slowly introduce to pasture, graze young stock before adults, strip-grazing, ionophore abx (monensin or Iasalocid) BEFORE they go on pasture
Moldy Sweet Potato Toxicity
- Fusarium solani fungus on moldy sweet potatoes
- 4-hydroxymyoporone hepatotoxin produced by potato and converted to pneumotoxin 4-ipomeanol by fungus
- toxin ingested and carried to lungs
- Clara cells convert to reactive metabolite
- damage to clara cells and pneumocytes (similar to ABPEE)
Perilla Mint Toxicity
- ketone toxin similar to 4-ipomeanol in sweet potatoes
- mature cows most commonly affected
- seed/flower most toxic
Acute severe exposure to what gases can cause ARDS
Ammonia H2S CO2 Methane Nitrogen dioxide (silo gas) Zinc oxide Smoke inhalation
Milk Allergy
- sudden onset urticaria, diarrhea, resp. Distress, pulm. Edema at end of lactation
- hereditary in Channel Island breeds
- type I hypersensitivity to casein
- tx: antihistamines, corticosteroids, milk the cow
Hypersensitivity Pneumonitis
- Allergic resp. Dz due to inhalation of organic dusts containing spores
- usually in older housed animals during the winter
- chronic progressive dz
- Type III hypersensitivity rxn
- CS: increased expiratory effort, resp. Distress, depression, wt. loss
- Dx: CS, TTW, Ab to M. Faeni?
- Tx: remove moldy hay, steroids in severely affected individuals
Parasitic Pneumonia (Cattle)
- Dictyocaulus viviparus trichostrongylid nematode
- affects cattle
