1. Chapter 22: Diseases of the nervous system
Lecture
NS overview
Bacterial diseases
Viral diseases
Fungal diseases

2. The nervous system 2 components: - CNS: brain and spinal cord
- PNS: nerves extending
from CNS
Meningitis- infection of the
meninges
Encephalitis- infection of
the brain
Protection via blood-brain
barrier

3. Meninges and cerebrospinal fluid

4. Etiologies of bacterial meningitis

5. Neisseria meningitidis, Meningococcal meningitis
Symptoms
Due to endotoxin
Rash that doesn’t fade when
pressed
Throat infection- bacteriemia-
meningitis

6. Clostridium tetani- tetanus
Symptoms
Due to tetanospasmin toxin
Spastic paralysis

7. Clostridium botulinum- botulism
Symptoms
Due to exotoxin
(Types A, B, and C)
Flaccid paralysis
Blurred vision
Nausea, no fever

8. Mycobacterium leprae- Hansern’s Disease or leprosy
Symptoms
Tuberculoid
PNS infected
Skin shows immune reactions
Lepromatous
Skin cells infected
Disfiguring nodules
Less immune response
Tissue necrosis

9. Polio virus-
Poliomyelitis

10. Rhabdoviridae- rabies
Symptoms
First stage
Mild and varied
CNS infected
Hydrophobia
Mouth/pharyngeal spasms
Meningitis/ encephalitis

11. Diseases in Focus 22.2 (2 of 3)

12. Diseases in Focus 22.2 (3 of 3)

13. Cryptococcus neoformans Meningitis (Cryptococcosis)
Soil fungus associated with pigeon and chicken droppings
Transmitted by the respiratory route through dried contaminated droppings
In the immunocompromised, it spreads through blood to the CNS
Mortality of up to 30%
Treatment: amphotericin B and flucytosine

14. Figure 22.15 Cryptococcus neoformans.

15. Nervous System Diseases Caused by Prions
Prion: abnormally folded protein
Causes normal proteins in the brain tissue to become abnormally folded
Leads to spongiform degeneration
Chronic and fatal
Transmissable spongiform encephalopathies (TSE)
Sheep scrapie
TSE in sheep
Chronic wasting disease
TSE in deer and elk
Bovine spongiform encephalopathy (BSE)
Mad Cow Disease
Possibly due to cattle eating feed containing bone meal from scrapie-infected sheep

16. Transmissible spongiform encephalopathies (TSE)-
Creutzfeldt-Jakob Disease
Symptoms
Prion disease
Loss of motor control
Death

17. Transmissible spongiform encephalopathies-
Kuru (TSE in humans that is caused by cannibalism)