Bacterial Infections of the CNS

Question 1

What is the number 1 virulence factor for spirochetes?

Answer 1

Immune System Evasion

Question 2

What is Lyme Disease caused by?

Answer 2

Borrelia burgdorferi

Question 3

How would one identify B. burgdorferi on microscopy?

Answer 3

Giemsa, Silver stain, Immunofluorescence, Std. Microscopy

Question 4

B. burgdorferi vector? Source?

Answer 4

Ixodes tick; White footed mouse/wood rate

Question 5

How long must a tick be attached to transfer B. burgdorferi? What type of the Ixodes tick transfers the disease?

Answer 5

24-48 hours; Nymph

Question 6

Describe the process of culture from humans for B. burgdorferi

Answer 6

Culture from human is very difficult

Question 7

Describe the pathogenesis of B. burgdorferi

Answer 7

Bite -> Bacteremia -> Heart, Joints, CNS; Primarily immune evasion

Question 8

Describe the process of B. burgdorferi evolution

Answer 8

1. Erythema chronicum migrans (bullseye rash) spread; only seen in a few patients
2. Months - cardiac and CNS involvement: myocarditis, heart block, aseptic meningitis, Bell’s palsy, particularly bilateral facial nerve palsy
3. Months - arthritis in large joints (knee) chronic progressive CNS involvement
4. Post Tx: Lingering fatigue, joint pain, CNS involvement

Question 9

What labs are generally used to Dx Lyme Disease?

Answer 9

Serology (ELISA) or IF, confirm with WB or PCR

Question 10

Tx for mild Lyme, late Lyme? What is the Jarisch-Herxheimer Rxn? Prevention of LD?

Answer 10

Doxycycline/Amoxicillin; Ceftriaxone; Flu-like Syx following Tx for Lyme; Long pants! Check skin!

Question 11

What two pathogens cause relapsing fever?

Answer 11

Borrelia recurrentis and Borrelia hermsii

Question 12

What are the vectors and reservoirs of B. recurrentis and hermsii respectively?

Answer 12

1. recurrentis - body louse, humans
2. hermsii - soft ticks, small mammals

Question 13

Describe the pathogenesis of b. recurrentis and hermsii infection

Answer 13

Enter blood from bite -> reproduce -> malaise/organ dysfunction ->Abs select for bug not recognized by immune system -> disease resumes -> repeat

Question 14

How would you Dx B. recurrentis or hermsii? Tx? What should patients expect following Tx?

Answer 14

Blood smear (uscopically visible), culture; Tetracycline; Jarisch-Herxheimer Rxn

Question 15

How would one obtain a Leptospira infection?

Answer 15

Ingesting infected water/soil or swimming in contaminated water

Question 16

Describe the pathogenesis of Leptospirosis

Answer 16

Dog/Animal urine -> water/soil -> swim/eat water/soil/rub on mucous membranes -> bacteremia -> Biphasic disease

• Crappy Phase: Fevers chills, intense headache, conjunctival suffusion
• Resolution of bacteremia
• Immune Phase: Bacteria expressed toxins in organs

1. Liver: jaundice
2. Kidney: uremia
3. Lungs: hemorrhage
4. aseptic meningitis

Question 17

How would one Dx Leptospirosis?

Answer 17

Take a good Hx; Blood/urine cultures normally negative; Specific serology by CDC;

Routine blood work reveals: anemia, elevated BUN and creatinine (kidney), bilirubin and alkaline phosphatase (liver), elevated CK (muscle damage)

Question 18

Tx for Leptospirosis. What should a patient experience following Tx?

Answer 18

Penicillin G or Doxycycline or 3rd gen cephalosporins; Jarisch-Herxheimer Rxn

Question 19

A pregnant patient with no allergies is to be treated for Lyme Disease. What is the Tx of choice? Amoxicillin or Doxycycline?

Answer 19

Amoxicillin! Doxycycline is contraindicated for pregnancy