Bacterial Infections of the CNS

Question 1

True or False: A major problem with spirochete infections is acquired antibiotic resistance

Answer 1

FALSE: spirochetes show little acquired antibiotic resistance

Question 2

List the unique aspects of spirochetes

Answer 2

• Wide variety of transmission methods
• cross easily into blood stream
• primary virulence factors are for immune evasion
• diagnosis is challenging
• Jarisch-Herxheimer reaction

Question 3

True or False: Borrelia are too small to see with standard microscopy

Answer 3

FALSE: borrelia are large enough to see with standard microscopy

Question 4

What is the vector for B. burgdorferi?

Answer 4

Ixodes ticks

Question 5

B. burgdorferi is stainable with what stain?

Answer 5

Giemsa, and silver

Question 6

Lyme disease is transmitted primarily by _____ ticks during the ________.

Answer 6

1-nymph

2- summer

Question 7

How long does it take for a tick to transmit Lyme disease?

Answer 7

24-48 hrs

Question 8

Describe the three stages of lyme disease

Answer 8

Stage 1: Flu-like with erythema migrans rash
Stage 2: MSK and neuro sx, myocarditis, heart block, aseptic meningitis, Bell’s palsy (bilateral facial nerve palsy)
Stage 3: additional neuro sx, arthirits in large joints

Question 9

After being treated for Lyme disease, what type of symptoms may persist?

Answer 9

fatigue, joint pain, mental status changes

Question 10

How do you diagnose Lyme disease?

Answer 10

History of outdoor activity, season of activity, geographic location, serology may confirm exposure but not right away

Question 11

How do you treat Lyme disease?

Answer 11

amoxicillin, doxycycline, alt: ceftriaxone, cefuroxime axetil for 10-30 days

Question 12

What is the Jarisch-Herxheimer reaction?

Answer 12

flu-like sx 24 hrs after treatment, thishelps confirm the dx of lyme disease

Question 13

When is prophylactic doxycycline for Lyme disease recommended?

Answer 13

in areas where the percentage of infected ticks is high, if someone has been bitten and the tick was in place for >24 hrs

Question 14

When does Lyme disease cause high fever?

Answer 14

WHen there is a coinfection with erlichia or babesia

Question 15

what are some characteristic symptoms caused by european ticks?

Answer 15

bluish borrelial lymphocytoma on earlobe or nipple

Acrodermatitic Chronica Atropicans

Question 16

what is the vector for B. recurrentis?

Answer 16

body louse (seen in Africa and homeless shelters)

Question 17

What is the vector for B. hermsii?

Answer 17

soft ticks (ornithodoros)

Question 18

How many relapses typically occur with B. recurrentis? B. hermsii?

Answer 18

1 relapse in B. recurrentis (MORE SEVERE)

3 relapses in B. hermsii

Question 19

What is the reservoir for B. recurrentis? B. hermsii?

Answer 19

B. recurrentis: HUMANS ONLY

B. hermsii: small mammals and ticks (more common in US)

Question 20

Describe the pathogenesis of B. recurrentis and B. hermsii?

Answer 20

the borrelia immediately enter the blood stream from the bite site and multiply in many tissues–> malaise and organ dysfunction–> neutralizing Ab and IL-10 halt disease–> antigenic variation allows bacteria unrecognized by Ab to predominate –> disease resumes–> immune syst mounts a new response

Question 21

How do you diagnose relapsing fever?

Answer 21

hx of tick bite or louse bite,
fever
chills
headaches
organ dysfunction
peripheral blood smear: spirochetes usually visible during febrile periods

Question 22

How do you treat relapsing fever?

Answer 22

tetracycline, doxycycline, erythromycin: peds, pregnant, nursing

Question 23

What is the drawback of doing a culture for borrelia?

Answer 23

very slow 2-6 wks

Question 24

What infection is characterized by multiple episodes of 3-5 days of high fever, with low BP and a well week in between episodes?

Answer 24

relapsing fever: B. recurrentis and B. hermsii
other sx: chills, arthralgias, N/V, mental status changes, nonproductve cough, diarrhea, dizziness, neck pain, photophobia, rash, dysuria

Question 25

True or False: Leptospira are visible with standard microscopy

Answer 25

FALSE: leptospira are too small to see by standard microscopy, must use darkfield

Question 26

What is another name for leptospirosis?

Answer 26

bilious typhoid

Question 27

How is leptospirosis transmitted?

Answer 27

humans swimming in contaminated water (bacteria cross mucus membranes)
or
ingesting contaminated food/ drink
P2P is possible but rare

Question 28

What are the two phases of leptospirosis?

Answer 28

phase 1: acute, 5-7 days high fever, rigor, headache, nausea - leptospira circulate in blood and multiply in blood vessel endothelium–> vasculitis, initial sepsis
phase 2: delayed/ immune - jaundice, renal failure, lung hemorrhage, aseptic meningitis, DIC, HUS, TTP, vasculitis
***both phases show conjunctival suffusion

Question 29

How do you treat leptospirosis?

Answer 29

PCN G, alt: doxy, third-gen cephalosproins

Question 30

Describe anicteric and icteric leptospirosis:

Answer 30

anicteric = normal course (biphasic)
icteric= Weil Disease, increased mortality, phase 2 follows phase 1 more quickly

Question 31

How do you diagnose leptospirosis?

Answer 31

history, serology, blood and urine cultures (usually neg), elevated BUN, creatinine, bilirubin, alk phos, serum CK

Question 32

What are virulence factors of B. burgdorferi?

Answer 32

immune evasion: Lmp1

manganese transporter: BmtA

Question 33

What are virulence factors of B. recurrentis and B. hermsii?

Answer 33

Complement resistance: HcpA

Question 34

What are virulence factors of L. interrogans?

Answer 34

Hemolysis: SphH
Nephrotoxin: Loa22

Question 35

What disease is caused by L. interrogans?

Answer 35

Leptospirosis

Question 36

Is gram staining useful for spirochetes?

Answer 36

NO, they would be gram (-) but it doesn’t work