Lecture 11

Question 1

What does the central nervous system consist of?

Answer 1

Brain and spinal chord

Question 2

What does the peripheral nervous system consist of?

Answer 2

All nerves that branch of the brain and spinal chord

Question 3

Infection in CNS?

Answer 3

1. invasion of bloodstream by pathogen
2. inflammation of blood brain barrier (impermeability affected)
3. penetration of blood brain barrier by pathogens

Question 4

Encephalitis

Answer 4

inflammation of the brain itself

Question 5

Meningitis

Answer 5

Inflammation of the membranes covering the brain and spinal chord

Question 6

Symptoms of encephalitis and meningitis

Answer 6

Fever, headache, stiff neck, coma, death
Neurological damage in survivors

Question 7

Which bacteria is meningitis caused by:

Answer 7

Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae

Question 8

How are bacterial pathogens protected from immune system?

Answer 8

by a capsule

Question 9

Neisseria Meningitidis description

Answer 9

Gram negative diplococci
* Meningococcus
* Strictly aerobic organism
* Non-motile
* Non-spore-forming
* Polysaccharide capsule
* Frequently present in nose
and throat (carrier-state)
Most often associated with disease: A, B, C, Y, and W135

Question 10

Acute Bacterial Meningitis

Answer 10

Begins with throat-infection,
leading to bacteremia and
eventually meningitis
* Symtoms: fever & altered mental
status, severe headache, nausea,
vomiting, & photophobia
* Usually occurs in children under
age of 2

Question 11

Fulminant Meningococcemia

Answer 11

In 5 to 15 % of patients with
meningococcal disease
* Sudden appearance of skin
lesions
* No signs of meningitis
* Development of pulmonary
insufficiency within few hours
* High death rate within 24 h
despite appropriate antibiotic
therapy and intensive care

Question 12

Neisseria meningitidis: Pathogenesis

Answer 12

Attachment:
* to epithelial cells of the nasopharyngeal and oropharyngeal
mucosa
* Invasion:
* by crossing the mucosal barrier, and entering the bloodstream
* Survival in Blood:
* by resistance against phagocytosis, blood-borne bacteria may
enter the central nervous system and cause meningitis

Question 13

Virulence factors: Neisseria Meningitidis

Answer 13

IgA protease–> cleaves IgA
LPS–> fever and shock
polysaccharide capsule–>antiphagocytotic
no exotoxins

Question 14

Neisseria meningitidis: Isolation & Identification

Answer 14

Specimens taken from blood, cerebrospinal fluid, and
nasopharyngeal secretions
* Cultivation of bacteria on chocolate or blood agar
* Plates should be incubated in a candle jar or CO2 incubator
* The presence of oxidase-positive colonies and Gram-negative
diplococci provides a presumptive identification of N. meningitidis

Question 15

Neisseria meningitidis: Prophylaxis and Therapy

Answer 15

Group A, C, Y, and W135 capsular polysaccharide vaccines
available, but ineffective in infants
* Vaccine (Bexsero) against group B approved in EU in 2013
* Routine vaccination in industrialized countries currently not
recommended
* Treatment with Cephalosporins
* Although penicillins and cephalosporins do not penetrate the normal
blood-brain barrier, they readily penetrate the blood-brain barrier
when the meninges are acutely inflamed

Question 16

Haemophilus influenzae

Answer 16

Gram negative rod associated with respiratory tract diseases
* misleading name: pathogen does not cause influenza
* Cause of meningitis in young children: 6 – 12 months
* Clinical findings indistinguishable from other meningitis
* Also frequent cause of otitis media and sinusitis
* May cause epiglottitis: life threatening disease