Lecture: Path of Inflammatory conditions (Farina) Flashcards

1
Q

Neurotropism of organisms

A
  • ability of organisms to breach the BBB and BCSFB determines their neurotropism
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2
Q

Inflammatory conditions

Examples

A
  • Names by location of imflammatory cells
  • Examples
    • Meningitis
    • Encephalitis
    • Myelitis
    • Meningoencephalitis
    • Meningomyelitis
    • Meningoencephalomyelitis
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3
Q

Bacterial infections

A
  • 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
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4
Q
A
  • Equine bacterial meningitis
  • Purulent material
  • Red angry brain
  • Pus around the spinal cord
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5
Q
A
  • Goat-brain abscess
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6
Q
A
  • Pig - purulent meningitis secondary to otitis media/interna
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7
Q

Listeriosis

Caused by/affects

CS

A
  • 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
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8
Q

Listeriosis

Common place for lesions

Pathogenesis

A
  • 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
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9
Q
A
  • Listeriosis
  • Dark red areas are areas of inflammation
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10
Q
A

Listeriosis

  • Big clusters of degenerate neutraphils
  • Microabscesses
  • gram positive bacteria
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11
Q

Infectious thrombotic meningoencephalitis (ITME)

Caused by

Affects

Normally found…

A
  • Caused by Histophilus somni
  • Affects
    • young cattle in feedlots
    • sheep
  • Organism normally found in upper GI, upper repiratory and urogenital tract of healthy animals
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12
Q

Thrombotic meningoencephalitis (TME)

A
  • Septicemia
    • cerebral vasculitis with hemorrhage
    • necrosis
    • thrombosis
  • Gross lesions
    • multifocal hemorrhage and necrosis
  • Histologic lesions
    • vasculitis
    • thrombosis
    • infarction
    • neutrophilic meningoencephalitis
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13
Q
A
  • Thrombotic meningoencephalitis (TME)
    • random distribution
    • Red = hemorrhage
    • Blue = inflammation
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14
Q
A
  • Thrombotic meningoencephalitis (TME)
    • Can see vessel wall at times, then lose it
    • Also see a thrombus
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15
Q
A
  • Fibrinoid vascular necrosis
    • fibrin and cellular debris replacing normal tissue
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16
Q

Viral infections

A
  • 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
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17
Q

Rabies

A
  • Can affect all mammals
  • Principal reservoirs in us
    • skunks
    • foxes
    • raccoons
    • bats
  • tropism for CNS and salivary gland
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18
Q

Rabies

Mechanism of infection

Lesions

A
  • 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
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19
Q
A

Rabies

  • Perivascular cuffing above (inflammation around vessel)
  • Meningoencephalitis below
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20
Q
A

Rabies inclusions in purkinje cell of a dog with rabies

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21
Q

Pseudorabies

A
  • 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
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22
Q

Pseudorabies

Mechanism of infection

CS in things other than pigs

CS in pigs

CS young pigs

CS Sows

A
  • 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
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23
Q
A

Pseudorabies

  • Perivascular cuffing
  • Nuclear inclusions (cell in middle)
    • red stuff in middle is inclusion and blue stuff at border of red stuff is chromatin
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24
Q

Arboviruses

Types

Species affected

A
  • 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
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25
Q

Arboviruses - EEE, WEE, SLE

Transmission

Lesions

A
  • 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
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26
Q

Arboviruses - WNV

Most commonly affects

Transmission

Lesions

A
  • 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

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27
Q
A
  • EEE
  • Neutraphils out in the tissue
  • Fulminant, neurologic disease
28
Q
A
  • WNV (more boring than EEE)
  • Perivascular inflammation and gliosis (not inflammatory cells)
  • Bottom picture looks more typically viral than EEE
29
Q

Lentivirus

(Caprine arthritis encephalitis virus (CAE)

CNS signs

CS , adults

Lesions

A
  • Nervous sytem signs seen in kids 2-4 months old
  • CS
    • hind limb ataxia
    • paresis
    • paralysis
    • often death
  • CS adults
    • arthritis
    • mastitis
    • pneumonia
  • Lesions
    • non-suppurative leukoencephalomyelitis
    • demyelination

*Lesions tend to be more in white matter

30
Q

Lentiviruses

Visna-maedi virus

CNS

CS

Lesions

A
  • Neuro signs usually occurs in sheep > 2 yo
  • CS
    • hindlimb ataxia
    • trembling of lips
    • progressive hindlimb paralysis
    • death secondary to infectio or starvation
  • Also causes
    • pneumonia
    • mastitis
    • arthritis
  • Lesions
    • nonsuppurative meningoencephalitis affecting mostly white matter
    • demyelination
31
Q
A
  • CAE
    • area of inflammation at the periphery out in white matter
    • Perivascular cuffs
  • Below
    • large perivascular cuffs
    • Gliosis (nonsuppurative)
32
Q

Canine distemper virus

Morbillivirus

Affects…

A
  • Canids
  • Procyonids
  • mustelids
  • some large cats
33
Q
A
  • Classic gross lesion for canine distemper
    • hard pad disease (hyperkeratosis of foot pad)
    • May not be common lesion, don’t rule out distemper if you don’t this lesion
34
Q

Most viruses cause

A

Nonsuppurative encephalitis

35
Q
A

Canine distemper virus

  • perivascular cuffing and gliosis

Below

  • Non-suppurative, mostly lymphocytes
36
Q
A

Canine distemper

  • Intranuclear and intracytoplasmic inclusions (very rare)
37
Q

Equine herpesviral myeloencephalopathy

Caused by

Spread

Replication

A
  • Caused by
    • Mainly EHV-1, also EHV-4
  • Spread
    • inhalation of nasal aerosols
    • contact with infected fetus/placenta
    • direct contact
  • Replication
    • in endothelial cells
    • causes thrombo-occlusive, necrotizing vasculitis
38
Q

Equine herpesviral myeloencephalopathy

Gross lesions

Histo

A
  • Gross lesions
    • none
    • random foci of hemorrhage in brain
    • severe cases may have small foci of hemorrhage/malacia
  • Histo
    • non-suppurative necrotizing vasculitis and thrombosis
39
Q
A

Equine herpesviral myeloencephalopathy

  • lose definition of vessel wall (bottom left)
  • hemorrhage, vacuolization, edema, necrosis
40
Q

Fungal infections

Features

A
  • Many species can affect CNS
    • usually in immunocompromised patients
41
Q

only fungus with real predilection for CNS

A

Cryptococcus neoformans

42
Q

Cryptococcus neoformans

about

A
  • Affects cats, dogs, and horses
  • Usually starts as a nasal or sinus infection and enters brain via direct extension through cribiform plate
  • May also spread to brain hematogenously from pulmonary infection
43
Q

Cryptococcus neoformans

Gorss lesions

Histo

A
  • Gross lesions
    • grey, gelatinous foci in brain and meninges
  • Histo
    • inflammatory response variable
      • none-to granulomatous
    • Thick non-staining mucopolysaccharide capsule looks like ‘soap-bubble’ in tissue sections
44
Q
A

Cryptococcal encephalitis

  • random grey foci

Below

  • Gelatinous lesions
45
Q
A

Cryptococcal encephalitis

Below

  • Clear bubbles: big thick non-staining mucoid capsule
46
Q
A

Cryptococcal encephalitis - mucicarmine stain

  • illustrates yeast budding (differentiates from blastomycosis although blasto not really seen in brain)
47
Q

Equine protozoal encephalomyelitis

A
  • Sarcocystis neurona
  • Affects horses
  • Exact pathogenesis not completely understood
    • sporocytsts ingested - multiply in viscera - transported to CNS
48
Q

Equine protozoal encephalomyelitis

Gross lesions

Histo

A
  • Gross lesions
    • typically none
    • may see random foci of hemorrhage and necrosis
  • Histo
    • hemorrhage
    • necrosis
    • perivascular cuffs of lymphocytes
    • macrophages
    • neutrophils and eosinophils
    • astrocytosis
49
Q

Eosinophils + Giant multi-nucleated cells = think about….

A

EPM

50
Q

EPM

Why are organisms not seen?

A
  • Vets start treatment immediately and go for long-term
51
Q
A

EPM

  • perivascular cuffs
  • some gliosis

Below

  • crescent or round-shaped zoites
52
Q

Toxoplasmosis

A
  • Toxoplasma gondi
  • Affects many mammals
    • new world monkeys and Australian marsupials susceptible to infection
  • infection often seen with immunosuppressive conditions
    • Cats with FeLV-FILV
    • Dogs with distemper
53
Q

Toxoplasmosis

Gross lesions

Histo

A
  • Gross lesions
    • hemorrhage and necrosis
  • Histo
    • necrosis
    • hemorrhage
    • perivascular lymphohistiocytic cuffs
    • tachyzoites and cysts containing bradyzoites
54
Q
A

Toxoplasmosis

  • Perivascular cuffs
  • holes in the brain
  • liquifactive necrosis

Below

  • necrosis
  • perivascular inflammation
    • mononuclear (a lot of glial cells)
55
Q
A

Toxoplasmosis

  • Little protozoal zoites
56
Q

Spongiform diseases

A
  • Transmissible spongiform encephalopathies (TSE)
    • caused by prions (abnormal isoforms (PrPSc) of a normal cellular protein (PrPc)
    • Exact pathogenesis not understood
      • abnormal protein may serve as a scaffold
57
Q

Spongiform diseases

Transmission

TSEs in animals

A
  • transmission
    • appears to be primarily horizontally by consuming infected feed
  • TSEs in animals
    • Bovine spongiform encephalopathy (BSE)
    • Scrapie (ovine spongiform encephalopathy)
    • Chronic wasting dz (CWD, affects cervids)
    • Feline spongiform encephalopathy (FSE)
    • Transmissible mink encephalopathy (TME)
58
Q

Spongiform diseases

Lesions

A
  • Lesions
    • intracytoplasmic neuronal vacuolation
    • astrocytosis
59
Q
A

Scrapie

  • Vaculization
60
Q

Neoplasia

Meningioma

Seen in

Gross lesion

A
  • Seen in
    • cats
    • dogs
    • horses
    • cattle
    • sheep
  • Gross lesion
    • located on meningeal surface of CSN
    • Well-demarcated, encapsulated expansile masses
    • grey-white to red-brown
61
Q
A

Meningioma

62
Q

Neoplasia

Astrocytoma

Reported in

Gross lesion

Common sites

A
  • Reported in
    • brachycephalic breeds
    • cats
    • cattle
  • Gross lesion
    • poorly demarcated, firm, grey-white masses in white matter and grey matter
    • Well differentiated neoplasms may be difficult to differentiate from surrounding brain matter
  • Common sites
    • pyriform and temporal lobes
63
Q
A

Astrocytoma

  • tends to look like normal brain tissue
  • Mass effect
  • Not symmetrical
64
Q

Neoplasia

Oligodendroglioma

Reported in

Gross lesion

A
  • Reported in
    • dogs (esp brachycephalic breeds)
    • cats
    • cattle
  • Gross lesion
    • grey to pink-red
    • soft to gelatinous mass in white or grey matter of cerebrum and brainstem
65
Q
A

Oligodendroglioma

  • gelatinous with hemorrhage
66
Q
A

Metastatic hemangiosarcoma

Cancer of endothelial cells

67
Q
A

Metastatic melanoma