Exam 4: Nervous System Infections

Question 1

two parts of the nervous system

Answer 1

Peripheral nervous system (PNS)

central nervous system (CNS)

Question 2

neurotransmitters

Answer 2

chemical messengers released by neurons in response to stimuli

Question 3

meninges

Answer 3

in the nervous system the meninges are 3 layers of tissue that surround the brain and spinal cord

Question 4

cerebrospinal fluid

Answer 4

CSF
most common sample type to detect infections affecting the CNS
-lumbar puncture

Question 5

meningitis

Answer 5

inflammation of the meninges

Signs symptoms: fever/chills, headache, confusion, nuchal rigidity, petechial rash

Question 6

bacterial meningitis

Answer 6

less common
more serious
CSF Testing:
-pressure increased
-WBC count; increased neutrophil
-protein very increased
-glucose very decreased

Question 7

viral meningitis

Answer 7

more common
less serious
CSF testing:
-pressure-normal
-WBC count; increased lymphocytes
-protein increased
-glucose normal

Question 8

Enteroviruses:

Answer 8

Characteristics: RNA virus family
Diseases: meningitis (viral)
Transmission: respiratory droplets, oral-fecal
Virulence: cross blood-brain barrier
Lab diagnosis: nucleic acid amplification (NAAT)/PCR
Prevention: hygiene

Question 9

Neisseria meningitidis

Answer 9

Characteristics: Gram negative diplococcus
Diseases: meningitis, meningococcemia
Transmission: respiratory droplets, normal microbiota of URT
Virulence factors: capsule, endotoxin
Lab diagnosis: routine culture and smear
Prevention: conjugate vaccine

Question 10

Cryptococcus neoformans

Answer 10

Characteristics: yeast
Diseases: meningitis
Transmission: inhalation of spores, opportunistic pathogen; infects immunocompromised
Virulence factors: capsule, survival in macrophages
Lab diagnosis: fungal culture and smear, rapid tests: agglutination test and ICA

Question 11

naegleria fowleri

Answer 11

Characteristics: protozoan (ameba)
Diseases: primary amebic meningoencephalitis (PAM)
Transmission: water-borne
Virulence factors: crosses blood-brain barrier
Lab diagnosis: microscopic examination of cerebrospinal fluid (CSF)

Question 12

Clostridium botulinum

Answer 12

Characteristics: Gram positive, bacillus, anaerobe
Diseases: botulism=flaccid paralysis
Transmission: ingestion of endospores, ingestion of preformed toxin, entry of endospores into deep wound
Virulence factors: endotoxin production, botulinum toxin (exotoxin, neurotoxin)
Lab diagnosis: detection of toxin in patient’s stool or serum or food sample
Treatment: antitoxin, respiratory support
Prevention: avoid improperly preserved food, expose deep wounds to air

Question 13

Clostridium tetani

Answer 13

Characteristics: Gram positive, bacillus, anaerobe
Diseases: Tetanus=spastic paralysis
Transmission: entry of endospores through wound
Virulence factors: endospore production, tetanospasmin (exotoxin, neurotoxin)
Lab diagnosis: clinical diagnosis
Treatment: antitoxin, respiratory support
Prevention: toxoid vaccine, expose deep wounds to air

Question 14

comparing botulism and tetanus

Answer 14

Clostridium botulinum:
mechanism of disease
-neurotoxin prevents release of stimulatory neurotransmitters
-no muscle contraction
-flaccid paralysis
Clostridium tetani:
mechanism of disease:
-neurotoxin prevents release of inhibitory release of inhibitory neurotransmitters
-no muscle relaxation
-spastic paralysis