Lecture: Path of Inflammatory conditions (Farina) Flashcards
Neurotropism of organisms
- ability of organisms to breach the BBB and BCSFB determines their neurotropism
Inflammatory conditions
Examples
- Names by location of imflammatory cells
- Examples
- Meningitis
- Encephalitis
- Myelitis
- Meningoencephalitis
- Meningomyelitis
- Meningoencephalomyelitis
Bacterial infections
- Most commonly secondary to septicemia in young animals
- Septic emboli with endocarditis
- Abscesses from hematogenous spread or direct invasion
- usually through cribiform plate or from middle ear
- Equine bacterial meningitis
- Purulent material
- Red angry brain
- Pus around the spinal cord
- Goat-brain abscess
- Pig - purulent meningitis secondary to otitis media/interna
Listeriosis
Caused by/affects
CS
- Circling disease
- Caused by Listeria monocytogenes
- Most commonly affects ruminants
- Outbreaks usually associated with heavy feeding of silage
- CS
- Head tilt
- circling
- confusion
- depression
- head pressing
- unilateral facial nerve paralysis
- masticatory muscle paralysis
- purulent endophthalmitis
Listeriosis
Common place for lesions
Pathogenesis
- Lesions most common in brainstem
- Pathogenesis
- bacteria spread up the motor and sensory branches of the trigeminal nerve
- usually no gross lesions
- histologic lesions => microabscesses sometimes within foci of microgliosis
- Listeriosis
- Dark red areas are areas of inflammation
Listeriosis
- Big clusters of degenerate neutraphils
- Microabscesses
- gram positive bacteria
Infectious thrombotic meningoencephalitis (ITME)
Caused by
Affects
Normally found…
- Caused by Histophilus somni
- Affects
- young cattle in feedlots
- sheep
- Organism normally found in upper GI, upper repiratory and urogenital tract of healthy animals
Thrombotic meningoencephalitis (TME)
- Septicemia
- cerebral vasculitis with hemorrhage
- necrosis
- thrombosis
- Gross lesions
- multifocal hemorrhage and necrosis
- Histologic lesions
- vasculitis
- thrombosis
- infarction
- neutrophilic meningoencephalitis
- Thrombotic meningoencephalitis (TME)
- random distribution
- Red = hemorrhage
- Blue = inflammation
- Thrombotic meningoencephalitis (TME)
- Can see vessel wall at times, then lose it
- Also see a thrombus
- Fibrinoid vascular necrosis
- fibrin and cellular debris replacing normal tissue
Viral infections
- Most viruses have a generally similar appearance
- non-suppurative meningoencephalitis (+/- myelitis)
- Perivascular cuffing
- Gliosis: inc number glial cells, non specific
- +/- viral inclusions
- +/- neuronal degeneration/necrosis
Rabies
- Can affect all mammals
- Principal reservoirs in us
- skunks
- foxes
- raccoons
- bats
- tropism for CNS and salivary gland
Rabies
Mechanism of infection
Lesions
- Mechanism of infection
- bite wound - virus replicates in muscle cells near inoculation site - spreads to sensory paravertebral ganglia - virus travels along peripheral nerves to CNS
- Lesions
- nonsuppurative encephalomyelitis
- ganglioneuritis and parotid adenitis
- degree of inflammation and neuronal degeneration variable
- Negri bodies (Cytoplasmic inclusions) found most often in hippocampus in carnivores and purkinje cells in herbivores
Rabies
- Perivascular cuffing above (inflammation around vessel)
- Meningoencephalitis below
Rabies inclusions in purkinje cell of a dog with rabies
Pseudorabies
- Porcine herpesvirus-1
- Can affect all common domestic species
- Spread between pigs
- thought to be most commonly due to contact of virus-infected secretions with abraded skin or nasal mucosa
- carnivores usually infected by consumption of infected pig meat
Pseudorabies
Mechanism of infection
CS in things other than pigs
CS in pigs
CS young pigs
CS Sows
- Mechanism of infection
- Local rxn at site of inoculation - spreads up related nerve to spinal cord - spread within CNS and out into other preipheral nerves
- CS in other things
- intense pruritis
- high mortality rate
- fever
- neurologic signs
- CS in pigs
- mild fever
- no pruritis
- CS in young pigs
- prostration
- convulsions
- muscle tremors/twitching
- may have high mortality rate
- CS in sows SMEDI
- abortion
- stillbirth
- mummified fetuses
Pseudorabies
- Perivascular cuffing
- Nuclear inclusions (cell in middle)
- red stuff in middle is inclusion and blue stuff at border of red stuff is chromatin
Arboviruses
Types
Species affected
- EE, WEE, VEE, SLE
- Eastern, Western, Venezuelan equine encephalomyelitis viruses
- St. Louis encephalitis virus
- Horses most commonly affected
- Other species affected
- birds
- humans
- cattle
- pigs
Arboviruses - EEE, WEE, SLE
Transmission
Lesions
- Transmission
- mosquito-borne
- Lesions
- Lymphohistiocytic and neutrophilic polioencephalomyelitis
-
Neutraphils may also infiltrate the grey matter
- unusual for a virus, typical or these viruses
- Gliosis, neuronal degeneration/necrosis, vasculitis, meningitis, and thrombosis can also be seen
Arboviruses - WNV
Most commonly affects
Transmission
Lesions
- Most commonly affects
- horses
- humans
- birds
- also squirrels, dogs, sheep and farmed alligators
- Mosquito-borne
- Lesions
- nonsuppurative polioencephalomyelitis
*Hits grey matter more. Doesn’t have the neutraphilic component that the others do