Neuropathology

Question 1

Name three infectious agents which affect the grey matter of the brain.

(x7 in total)

Answer 1

1. Rabies - Lyssavirus
2. Pseudorabies - suid Herpes virus 1
3. Teschen disease - Picornaviridae
4. Borna disease - Bornavirus
5. West Nile Encephalitis - Flavivirus
6. Louping ill - Flavivirus
7. Listeriosis - Listeria monocytogenes

Question 2

What is shown here?

Describe.

Answer 2

Negri bodies

Eosinophilic intracytoplasmic inclusion bodies

Question 3

What is shown here?

What cells make up the structure?

Answer 3

Glial nodule

Made up of microglia (macrophage-like) - activated rod cells - surrounding necrotic tissue

Question 4

What histological features are associated with pseudorabies?

Answer 4

• Non-suppurative
• Meningopolioencephalitis
• Glial nodules
• Neurophagia
• Neuronal nodules

Question 5

What is shown here?

Describe the lesion.

Answer 5

Neurophagic nodule

Microglia surrounding neurone

Question 6

What clinical presentation is associated with pseudorabies?

Answer 6

Pruritis

Violet scratching

Automutilation

Question 7

Swine polioencephalitis is also known as..

Answer 7

Teschen disease

Question 8

Viral polioencephalitis is characterised by what type of inflammation?

Answer 8

NON-SUPPURATIVE

Question 9

What histological features are associated with Techen disease?

Answer 9

• Non-suppurative
• Polioencephalitis
• Neuronal necrosis
• Glial nodules
• Neurophagia

Question 10

Neuronal death/ damage is characterised by what histological features?

Answer 10

Reversible: Chromatolysis (enlarged cytoplasmic volume and nucleus pushed to the periphery) - oxidative stress

Irreversible: Vacuolation and red hypoxic neurones (hypereosinophilic) - excitotoxicity and oxidative stress

Question 11

This viral disease is selective for the grey matter of hippocampus, cerebral cortex and brainstem.

What histological features are associated with this disease?

Answer 11

Bornavirus

• Non-suppurative
• Polioencephalomyelitis
• Neuronal degeneration
• Neuronophagia

Question 12

West nile encephalitis is characterised by what histological changes?

Answer 12

• Non-suppurative
• Polioencephalomyelitis

Also affects grey matter of the thoraco-lumbar spinal cord

Question 13

This flavivirus caused disease targets purkinje cells and causes gliosis and leptomeningitis.

Answer 13

Louping ill

Question 14

This bacteria causes encephalitis via retrograde axonal transport to the brain before causing multifocal microabscessation of the grey matter.

Answer 14

Listeria monocytogenes

Question 15

Name three infectious agents which affect the white matter of the brain.

Answer 15

• Canine distemper virus - morbilivirus
• Post-vaccinal distemper
• Maedi-visna - lentivirus

Question 16

What histological changes are associated with Maedi Visna virus?

Answer 16

• Granulomatous leukoencephalitis
• Lymphoplasmacytic infiltration
• Cavitation and malacia
• Choroiditis and meningitis

Question 17

What histological changes are associated with Canine distemper virus?

Remember two phases.

Answer 17

Demyelinating leukoencephalitis

• Acute: pale and demyelinated
• Chronic: non-suppurative w/ cavitation
• Post-vaccinal: 2 weeks post vaccination

Question 18

Name the four parasitic causes of polioencephalitis.

Answer 18

• Toxoplasma gondii
• Neospora caninum
• Sarcocystis neurona/ tenella
• Taenia multiceps

Question 19

What is GID?

What pathological changes does it cause?

Answer 19

Coerneurosis caused by Taenia multiceps

Brain fluid filled cysts

Question 20

How does the pathology of T. gondii differ between young and old animals?

Answer 20

Young: non-suppurative polioencephalitis and gliosis

Old: necrotising and granulomatous encephalitis

Question 21

Equine protozoal encephalomyelitis is caused by what pathological agent?

What histological signs are observed?

Answer 21

Sarcocystis neurona

Necrotising myelitis

Question 22

Name two causes of infectious meningitis.

Answer 22

• H. somni - sleeper syndrome
• GME - granulomatous meningoencephalitis

Question 23

This virus causes spinal cord inflammation (myelitis) and petechial/ ecchymoid haemorrhage of white and grey matter.

Answer 23

Equine herpes virus 1

Question 24

Name three viral causes of vasculitis.

Answer 24

• Classical swine fever: Pestivirus
• Rubarths disease: Canine adenovirus 1
• Malignant catarrhal fever: Ovine herpes virus 1

Question 25

What histological changes are associated with canine adenovirus 1?

Answer 25

Amphophilic inclusion bodies in endothelium and vasculitis & haemorrhage

Question 26

What histological changes are associated with classical swine fever?

Answer 26

• Disseminated
• Non-suppurative
• Meningoencephalitis

Question 27

Why is the CNS prone to ischemia?

Answer 27

High metabolic demand

No local storage

Few minutes of hypoxia leads to neuronal death

Question 28

What is the difference between hypoxia and ischemia?

Answer 28

Ischemia is a reduced blood flow of normally oxygenated blood

Hypoxia is normal flow of low oxygenated blood

Question 29

An ischemic brain infarct can result from what?

Answer 29

Vascular thrombosis

Emboli - tumour bacterial

Intracarotid injection

Question 30

Answer 30

Siderocalcinosis - depositation of Ca and Fe in vessel walls, occurs with ischemic infarcts

Question 31

How can infectious agents reach the brain?

Answer 31

Immune complexes

Within macrophages

Local accumulation within vessels

Retrograde axonal transport

Question 32

What is the difference between Hensen type 1 and 2 disc degeneration?

Answer 32

1 - extrusion of disc material

2 - protrusion without herniated disc