Final Exam: Nervous System Infections

Question 1

Peripheral nervous system (PNS)

Answer 1

Inputs and transmits information
Composed of nerves

Question 2

Central nervous system (CNS)

Answer 2

Integrates information received
Sends back an “action plan”
Composed of the spinal cord and brain
Physical damage to any of the CNS tissues can cause concussion or even coma

Question 3

Cerebrospinal fluid (CSF)

Answer 3

Produced by structures within the brain
Acts as a cushion

Question 4

Blood–Brain Barrier

Answer 4

Specialized blood vessels that deliver nutrients and oxygen to the CNS
Allows only a few types of molecules to pass from capillaries into the CNS
Very small molecules and lipophilic molecules can pass through these cells
These special capillaries protect the brain from infection by limiting pathogen access to this sensitive tissue

Question 5

Blood–Brain Barrier: Features

Answer 5

Bacteria require a very special set of virulence factors in order to slip through this barrier
Viruses have an easier time invading the CNS, but still encounter challenges
Nervous system infections are more likely to follow some injury to the system or develop if there is a problem with the immune system

Question 6

Meningitis

Answer 6

inflammation of the meninges
Viruses are the most common cause
Viral forms of meningitis are serious, but usually have a better prognosis than bacterial forms

Question 7

Encephalitis

Answer 7

inflammation of the brain
Viruses are the most common cause

Question 8

Meningoencephalitis

Answer 8

inflammation of meninges and brain

Question 9

Viruses cause the most common nervous system infections?

Answer 9

Poliomyelitis (Polio) - Etiological agent- Poliovirus
Rabies- Etiological agent – Rabies virus
Arboviral Encephalitis and Meningitis - Etiological agent Arboviruses (e.g., West Nile)

Question 10

Rabies: Transmission

Answer 10

Classic zoonosis
Virus enters into humans through an animal bite

Question 11

Rabies: Signs and Symptoms

Answer 11

Appear after 2–12 months
Fever, nausea, and paraesthesia around the wound (lasts 2–10 days)
Neurological symptoms (last a week)

Question 12

Rabies: Progession

Answer 12

Slowly replicates in the muscle cells
Incubation period (2–12 months)
Reaches the PNS and rapidly travels to the CNS
Invades brain cells then spreads back to PNS
Replicates and sheds from tissues that are well supplied with nerves (e.g., salivary glands)

Question 13

Rabies: Complication and treatment and prevention

Answer 13

Virus shuts down normal neuron functioning (Fatal)

Rabies postexposure prophylaxis: Antirabies antibodies
Inactivated (killed-virus) vaccine for rabies

Vaccination campaigns for dogs

Question 14

Diagnosing bacterial meningitis vs. viral meningitis

Answer 14

A lumbar puncture allows for CSF analysis to differentiate between viral and bacterial meningitis

Question 15

Diagnosing bacterial meningitis vs. viral meningitis: Cultures

Answer 15

Culture CSF: Viral meningitis will show no growth
Compare CSF and blood glucose levels: Viral meningitis does not affect CSF glucose levels

Question 16

Haemophilus Meningitis: Etiological agent and characteristics

Answer 16

Etiological agent – Haemophilus influenzae, Gram-negative bacteria
H. influenzae type b is the most serious invasive strain

Common in normal microbiota of healthy people

Question 17

Haemophilus Meningitis: Signs and symptoms, Complications and treatment

Answer 17

Sudden onset fever, headaches, stiff neck, confusion or disorientation

~100% mortality in untreated patients

Antibiotics, though even with antibiotics 3–6% of children who exhibit symptoms die

Question 18

Haemophilus Meningitis: Prevention

Answer 18

Hib vaccine

Question 19

Meningococcal Meningitis: Etiological agent

Answer 19

Neisseria meningitides
Gram-negative aerobe, Capsule
Serotypes A, B, C, W, X, and Y (B, C, and Y are most common in the U.S.)

Question 20

Meningococcal Meningitis: Signs/symptoms and treatment

Answer 20

similar to other types of bacterial meningitis (Rapid onset and course) with petechial rash progresses to larger bruise-like lesions

If not treated, death can occur within hours of fever onset, Antibiotics

Question 21

Meningococcal Meningitis: Prevention

Answer 21

Types of vaccines available in the US:
Meningococcal conjugate vaccines (Mentactra®, MenHibrix®, and Menveo®)
Meningococcal polysaccharide vaccine (Menomune®)
Serogroup B meningococcal vaccines (Bexsero® and Trumenba®)

Question 22

Common Causes of Bacterial Meningitis by Age Group

Answer 22

Newborns: E. coli, Group B Strep, Listeria monocytogenes
Infants/child: Streptococcus pneumonia, Neisseria meningitides, Haemophilus influenzae B type
Young Adults: Neisseria meningitides, Streptococcus pneumonia
Adults: Listeria monocytogenes, Neisseria meningitides, Streptococcus pneumonia