Nervous system pathology 2 Flashcards

1
Q

Name some examples of CNS vascular lesions

A
  • Ischaemic brain infarct
  • Ischaemic encephalopathy
  • Haemorrhagic brain infarct
  • Haematoma
  • Feline hypertensive encephalopathy
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2
Q

Define Atherosclerosis

A

Thickening or hardening of arteries

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3
Q

Which vascular condition affects the spinal cord?

A

Embolic encephalomyelitis

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4
Q

What are the clinical and diagnostic hallmarks of CNS vascular lesions?

A

Diagnostic hallmark: Focal or non-symmetrical multifocal haemorrhagic or malacic lesions
Clinical Hallmark: Acutely developing neurological symptoms without appreciable progression

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5
Q

Which features of the CNS make it susceptible to ischaemia?

A
  • High metabolic request (one third of total glucose)
  • Impossibility for local storage (e.g. glycogen)
  • Ischemia starts after 60% decrease of blood flow
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6
Q

What is the order in which the cells of the CNS are most susceptible to ischaemia?

A

Neurons > oligodendrocytes > astrocytes > microglia and endothelial cells

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7
Q

A few minutes of hypoxia leads to?

A

Neuronal cell death

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8
Q

What are the two ways that reduced oxygen levels reach the brain?

A
  • Ischaemia: reduced flow of normally oxygenated blood

- Hypoxia: normal flow of poorly oxygenated blood

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9
Q

What are 3 causes of an ischaemic brain infarct?

A
  • Vascular thrombosis
  • Emboli (e.g. mitral valve endocarditis, tumour emboli)
  • Intracarotid injection (horses)
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10
Q

How will the grey and white matter appear in an acute infarct infection?

A

Grey: hyperaemia and astrocytosis
White: rale area with ‘red neurones’ and spheroids

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11
Q

What is astrocytosis?

A

An abnormal increase in the number of astrocytes due to the destruction of nearby neurons from central nervous system (CNS) trauma, infection, ischemia, stroke, autoimmune responses or neurodegenerative disease.

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12
Q

How will the grey and white matter appear in a chronic infarct infection?

A

Grey: glial scar formation
White: liquefactive necrosis and astrogliosis

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13
Q

Under histology what does a ‘rusty’ colour represent?

A

Haemosiderin

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14
Q

What is the cause of hemosiderin being found in the CNS?

A

Accidental injection into arteries e.g. carotid, causing inflammation of vessels (phlebitis)

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15
Q

How will infarction in the spinal cord appear grossly?

A

Bruise like appearance – haemorrhage and necrosis of consecutive sections

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16
Q

If fibrocartilaginous material is seen within the lumen of small arteries what lesion will occur?

A

Fibrocartilaginous embolism

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17
Q

Which vascular condition is extremely common in horses?

A

Siderocalcinosis of vessels

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18
Q

What are 5 methods of infectious agents reaching the brain?

A
  • Deposition of immune complexes e.g. FIP
  • Direct infection of endothelial cells
  • Local accumulation of bacterial within vessels and consequent suppuration
  • ‘Trojan horse’ mechanism
  • Retrograde axonal transport
19
Q

Which different agents cause inflammation?

A
  • Virus
  • Bacteria
  • Parasites
  • Mycotic
  • Idiopathic
  • Autoimmune
20
Q

What are the different inflammatory patterns seen in the CNS?

A
  • Suppurative
  • Non-suppurative
  • Eosinophilic
  • Granulomatous
  • Polioencephalitis
  • Leukoencephalitis/ demyelination
21
Q

How does a gross CNS inflammatory lesion appear?

A

Malacic (softening), haemorrhagic, firm (granulomatous) and variably demarcated

22
Q

What is the specific term given to inflammation of the following anatomic locations:

  1. Brain
  2. Spinal cord
A
  1. Encephalitis

2. Myelitis

23
Q

What is the specific term given to inflammation of the following anatomic locations:

  1. Grey matter of the brain
  2. Grey matter of the brain and spinal cord
  3. White matter of the brain
  4. White matter of the brain and spinal cord
A
  1. Polioencephalitis
  2. Polioencephalomyelitis
  3. Leucoencephalitis
  4. Leucoencephalomyelitis
24
Q

What is the specific term given to inflammation of the following anatomic locations:

  1. Leptomeninges and brain
  2. Dura mater
  3. Choroid plexus
A
  1. Meningoencephalitis
  2. Pachimeningitis
  3. Choroiditis
25
Q

What are the major morphological hallmarks of a viral infection in the CNS?

A
  • Perivascular cuff
  • Non-suppurative inflammatory pattern
  • Often selectively targeting neurons or specific neuronal subpopulations (polioencephalitis/-myelitis)
  • Frequent involvement of meninges and choroid plexuses
26
Q

What is a perivascular cuff?

A
  • Accumulation of extravasated inflammatory cells within the perivascular space (Virkow-Robin space)
  • In the early stages this perivascular cuff is not inside the CNS because of the pia matter and meninges where the vessels are outside of these
27
Q

How does a purkinje neurone appear?

A

One cell thick layer of the large, flame shaped neurones

28
Q

Dark purple staining cells in the cerebellum are?

A

Granules

29
Q

What is the inflammatory pattern shown by rabies?

A

Mild non-suppurative polioencephalomyelitis (within the grey mater)

30
Q

Where does rabies virus travel in the body?

A

Inoculum site -> muscle -> axons -> CNS!

31
Q

What are the characteristic cells seen in Rabies infections?

A

Pathognomonic presence of eosinophilic round intracytoplasmic inclusions (Negri’s bodies in the cytoplasm of piramidal neurons of the hippocampus, carnivores, and Purkinje cells, ruminants, of the cerebellum)

32
Q

What are the 3 serial clinical phases of a rabies infection?

A

Prodromic, excitatory and paralytic

33
Q

What is the other form of Rabies?

A

Furious form

34
Q

Describe the inflammatory pattern of Canine distemper virus

A

Demyelinating leukoencephalitis (primary demyelination)

35
Q

Describe the 2 pathological stages of Canine distemper virus infection

A

Acute: pale demyelinated areas (gliosis and macrophages )

- Chronic: Non-suppurative inflammation with evident cavitation

36
Q

Describe post-vaccinal distemper

A

A non-suppurative polioencephalitis with abundant inclusion bodies occurring 2 weeks after CDV vaccination

37
Q

Which species is most commonly infected by West Nile encephalitis?

A

Horses

38
Q

What is the inflammatory pattern in West Nile encephalitis?

A

Non-suppurative Polioencephalomyelitis

39
Q

Which region is most specifically affected by West Nile encephalitis?

A

Grey matter of the thoraco-lumbar spinal cord

40
Q

Which histological changes can be seen in West Nile encephalitis

A

Within the grey matter
inflammatory cells accumulate around vessels
They migrate in the direction of CNS to infect neurones

41
Q

Which CNS virus most commonly affects sheep?

A

Maedi-visna virus

42
Q

Describe the inflammatory pattern of Maedi-visna virus

A

Granulomatous leukoencephalomyelitis

  • Inflammation of the brain and spine
  • Rich in macrophages
43
Q

What other pathological features are also observed with Maedi-visna?

A
  • Chronic lymphoplasmacytic infiltration (Granulomatous appearance)
  • Cavitation and malacia are frequently observed
  • Choroiditis and meningitis are commonly observed