EXAM 4 CHAPTER 26

Question 1

Why is there no normal flora associated with the cerebrospinal fluid?

Answer 1

It is sterile because of the meninges and the blood brain barrier.

Question 2

What are the 4 general mechanisms pathogens use to breach the blood brain barrier

Answer 2

Intercellular, transcellular, leukocyte facilitated, non-hematogenous

Question 3

Describe intercellular in regards to BBB

Answer 3

Virulence factors, toxins, or inflammation to pass between cells of the BBB.

Question 4

Describe transcellular in regards to BBB

Answer 4

Virulence factors to adhere, trigger uptake and pass through the cells of the BBB

Question 5

Describe leukocyte facilitated in regards to BBB

Answer 5

Trojan horse that infects peripheral blood leukocytes to directly enter the CNS

Question 6

Describe non-hematogenous in regards to BBB

Answer 6

Nonhematogenous entry allows pathogens to enter the brain without encountering the blood-brain barrier; it occurs when pathogens travel along either the olfactory or trigeminal cranial nerves that lead directly into the CNS.

Question 7

Define encephalitis

Answer 7

Inflammation of the brain. Same symptoms as meningitis with lethargy, seizures, and personality changes.

Question 8

Define meningitis

Answer 8

Inflammation of the meninges. Typical symptoms can include severe headache, fever, photophobia (increased sensitivity to light), stiff neck, convulsions, and confusion.

Question 9

Define meningoencephalitis

Answer 9

Inflammation of brain AND meninges. All three of these can lead to blindness, deafness, coma, and death

Question 10

What are the 3 most common causes of bacterial meningitis

Answer 10

Neisseria meningitis. Haemophilus influenzae. Streptococcous pneumoniae

Question 11

What is the best treatment for Neisseria meningitidis

Answer 11

Meningococcal vaccine

Question 12

What is the best treatment for Haemophilus influenzae

Answer 12

Hib polysaccharide conjugate vaccine

Question 13

What is the best treatment for streptococcus pneumoniae

Answer 13

Pneumococcal vaccine

Question 14

What is the cause of neonatal meningitis and how can it be prevented?

Answer 14

Streptococcus agalactiae. IV antibiotics in mom during labor stops spread

Question 15

Identify the mechanisms of virulence factors associated with tetanus

Answer 15

Caused by Clostridium tetani. When it infects a wound and produces TeNT which rapidly binds to neural tissues resulting in an intoxication of neurons

Question 16

What are the at risk populations for listeria?

Answer 16

Pregnant women, neonates, elderly, immunocompromised

Question 17

What causes Listeria and what are some facts about it

Answer 17

Listeria monocytogenes. Foodborne pathogens 20% of cases spread from GI tract to cause meningitis.

Question 18

What is the mechanism of rabies spread

Answer 18

Spread by bite of infected mammals

Question 19

What are the two presentations of rabies and their symptoms

Answer 19

Furious - hydrophobia, terror, confusion, cardio and respiratory failure, death. Paralytic - paralysis spreads from wound to rest of the body, coma, death.

Question 20

Prevention of rabies

Answer 20

Prevention is a prophylactic vaccine.

Question 21

What is the mechanism of pathology in transmission spongiform encephalopathy

Answer 21

They are typically transmitted by exposure to and ingestion of infected nervous system tissues, tissue transplants, blood transfusions, or contaminated fomites.

Question 22

Etiologic agent and risk factors of primary amoebic meningoencephalitis

Answer 22

Naegleria fowleri. Swimming in stagnant warm water.

Question 23

Symptoms and outcomes of primary amoebic meningoencephalitis

Answer 23

Early symptoms are severe headache and fever. Only 3/138 patients have survived. Cold therapy to reduce brain swelling.