Foundation - Overview of neuroinfectious diseases:

Question 1

Neuroinfectious diseases are diseases of the nervous system

Answer 1

caused by infectious ‘agents’
Not necessarily “living” organisms
(ex. virus, prions, toxons)

Question 2

Many neuroinfectious diseases are “neglected” diseases

Answer 2

• High medical burden
• Mostly absent from “developed” nations
• Treatments too expensive, or unavailable
• are drivers of poverty [acess to healthcare - alwasys improves poverty]

Question 3

Neglected tropical diseases (NTDs)

Answer 3

Group of 20 infectious diseases selected by WHO
- In 2014: Scabies and other ectoparasites
- In 2017: Mycetoma, chromoblastomycosis and other deep mycoses

many are CNS brain diseases

> 1.2 billion people affected and cost developing economies billions of dollars every year
- No longer restricted geographically - Economic globalization

Question 4

Few but diverse causative agents of NeuorInfect each tend to infect an specific area

Answer 4

1. Meninges - meningitis
2. Brain parenchyma - encephalitis
3. Spinal cord - myelitis

can be mixed - meningo-encephalo-myelitis

Also - Focal (contained) infections = abscess or cysts

Question 5

Clinical presentation imortant because

Answer 5

ex. meningiits - bacterial

Question 6

Entry routes into CNS

Answer 6

cellular monolayer (3 sub: transcellular, Trojan Horse, Patacellular)
infected contiguous tissue
nerve endings

Question 7

Through a cellular monolayer (Entry routes into CNS)

Answer 7

(endothelium - capilaries or epithelium-chorid Plexi)

a) transcellular
b) trojan horse - infected immune reponse (infecected itself)
c) paracullular

Question 8

Through infected contiguous tissue (Entry routes into CNS)

Answer 8

Mostly parasites and large pathogens (certain bacteria as well)

lice cell and gain access to next cell
continues - carving a whole

Question 9

Through nerve endings (Entry routes into CNS)

Answer 9

Common for viruses, who can hijack secreted vesicles in synapses

“nerve hopping”

infect neuron - hijact vessicular transport - release into synapes - moves to next neuron

Retrograde - into CNS
Anterograde - away from brain
(ex. rabies - does both)

Question 10

If Meningeal involvement

Answer 10

Symptoms
* Headache
* Fever
* Nausea
* Vomiting
* Neck pain (stiff neck)
* Reflex impairment

All related to increased intracranial pressure

CSF analysis
* High number of leukocytes, mainly polymorphonucleated cells
* High protein
* Very low glucose
* High lactate

All related to pathogen’s metabolism on the CSF [ need glucose to grow, protein from debree]

Question 11

If Parenchymal involvement

Answer 11

Symptoms
* Headache
* Fever
* Impairment of senses (go blind, deaf)
* Impairment of consciousness
* Psychological changes
* Focal neurologic deficits

All related to what area of the
brain is affected [where in parachma]

CSF analysis
* High number of leukocytes, mainly mononucleated cells
* High protein
* Normal glucose
* Normal to high lactate

The presence of the pathogen can usually be seen on brain scans [see inflamation]

Question 12

If Spinal cord involvement

Answer 12

Symptoms
* Back pain
* Muscle pain
* Partial paralysis
* Lower limbs paralysis
* Motor movement impairment

Related to an interruption of communication between CNS and PNS

CSF analysis - [not very usefull - depend on agent - mostly viruses]
* Inflammatory markers
* Immune cell population depends on pathogen
* Normal glucose
* Normal protein

Neuroimaging study must be performed

Almost always in conjunction with meningitis or encephalitis [rare only in spinal cord but can happen ex. polio]