Neuropathology: Infection and Inflammation

Question 1

What forms the blood-brain barrier?

Answer 1

brain microvascular endothelial cells, astrocytes and pericytes

Question 2

What is the function of the blood brain barrier?

Answer 2

maintains the neural microenvironment by regulating the passage of molecules into and out of the brain and any microorganisms/ toxins circulating in the blood

Question 3

What is the haematogenous spread of infection?

Answer 3

Bacteria with a direct cytotoxic effect on endothelial cells on the BBB

Question 4

What is the retrograde spread of infection?

Answer 4

Spread along axons of olfactory neurons or axons of the peripheral/ cranial nerves

Question 5

What does bacterial infection pathology usually look like?

Answer 5

usually charcterised by neutrophils

Question 6

What is the most common meningitis?

Answer 6

leptomeningitis

Question 7

What is meningitis most common in?

Answer 7

neonatal pigs, lambs, calves, goat kids and foals

Question 8

What may a space occupying lesion lead to?

Answer 8

cerebellar coning

Question 9

What is the name of a bacterial disease that can spread systemically and cause bacteraemia/ septic embolism that can then spread to the brain

Answer 9

purulent encephalitis/ malacia

Question 10

When does septic embolism/ thromboembolism to the brain occur?

Answer 10

May occur in severe bacteraemia when the blood swarms with bacteria

Question 11

What is the outcome of septic embolism

Answer 11

Cerebral abscess
Cerebral infarcts

Question 12

What bacteria causes thrombotic meningoencephalitis?

Answer 12

Histophilus somni (Gram-Neg coccobacillus)

Question 13

What does thrombotic meningoencephalitis look like grossly?

Answer 13

multifocal haemorrhage on the surface and cut sections of the brain

Question 14

What does thrombotic meningoencephalitis look like microscopically?

Answer 14

Haemorrhages and thrombosis with neutrophillic infiltrates

Question 15

What is the listeriosis route of infection?

Answer 15

Trigeminal neuritis
* penetrates damaged oral mucosa
* ascends the axons of the trigeminal nerve
* unilateral microabscessation in the medulla oblongata with inflammation

Question 16

What are the CNS features of canine distemper?

Answer 16

• Non-Suppurative encephalitis
• Demyelination
• Secondary gliosis
• inclusion bodies (cytoplasmic and nuclear)

Question 17

What are the 4 main routes of infection?

Answer 17

1. Haematogenous
2. Retrograde Spread
3. Direct Implantation
4. Direct Spread of Infection from other sites

Question 18

What is encephalitis?

Answer 18

Inflammation of the brain

Question 19

What is Myelitis?

Answer 19

Inflammation of the spinal cord

Question 20

What is Encephalomyelitis?

Answer 20

Inflammation of the brain and spinal cord

Question 21

What is ependymitis?

Answer 21

Inflammation of the ependyma

Question 22

What is choroiditis?

Answer 22

Inflammation of the choroid plexus of the ventricles

Question 23

What is meningitis?

Answer 23

Inflammation of the meninges

Question 24

What is leptomeningitis?

Answer 24

Inflammation of the leptomeninges

Question 25

What is pachymeningitis?

Answer 25

Inflammation of the pachymeninges

Question 26

When may a septic embolism occur?

Answer 26

Severe bacteraemias when the blood swarms with bacteria | outcome = septic abscess or cerebral infarct

Question 27

What bacteria causes Thrombotic Meningoencephalitis?

Answer 27

Histophilus Somni

Question 28

What is the pathogenesis of listeria monocytogenes?

Answer 28

* Penetrates the damaged oral mucosa * ascends axons of the trigeminal nerve * causes trigeminial neuritis and ganglioneuritis

Question 29

What is the function of microglia?

Answer 29

* Resident phagocytes * Similiar to macrophages- removal of individual neurons

Question 30

What do astrocytes react to?

Answer 30

They react non-specifically to many stimuli

Question 31

What are the four main routes of infection?

Answer 31

1. Haematogenous 2. Retrograde spread 3. Direct implantation 4. Direct spread from other sites

Question 32

What is encephalitis?

Answer 32

Inflammation of the brain

Question 33

What is myelitis

Answer 33

inflammation of the spinal cord

Question 34

What is encephalomyelitis?

Answer 34

inflammation of the brain and spinal cord

Question 35

What is the portal of entry of meningitis bacteria | E.coli, Pasteurella, Streptococcus, Salmonella

Answer 35

* Oropharyngeal * Respiratory * Umbilicus * Superficial wounds

Question 36

What are the usual histological features of Viral Infections?

Answer 36

* Neuronal necrosis * Chromatolysis * Inclusion bodies

Question 37

What are three ways viruses reach the CNS | most are part of systemic infections

Answer 37

* Systemic infection * display neurotropism * Reach teh CNS haematogenously * Peripheral nerves e.g rabies * Extension from the nasal cavity to the brain

Question 38

Name three equine viral diseases

Answer 38

* Bornavirus * West Nile Virus * Herpesvirus

Question 39

What is the pathogenesis of tachyzoites?

Answer 39

* they reach the CNS via the bloodstream * Intracellular replication * haemorrhage and inflammation

Question 40

What is granulomatous meningoencephalitis?

Answer 40

* T-medaited delayed-type hypersensitivity reaction * occurs in toy poodles and terriors

Question 41

Necrotisisng meningoencephalitis | non-infectious encephalitides

Answer 41

* occurs in pugs, maltese and chihuahua * autoimmune disease * grey matter of the cerebral cortex

Question 42

What is the pathogenesis of thrombotic meningoencephalitis?

Answer 42

* Bacterial lipoligosaccharides interact with platelets and endothelial cells-> causing vasculitis, thrombosis and septic infarct

Question 43

What does listeriosis cause in the medulla oblongata?

Answer 43

* microabscesation * inflammation of the overlying leptomeninges# * extension into the adjacent pons/ cranial cervical spinal cord