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MHD Block III > Spirochetes 9/8/15 > Flashcards

Spirochetes 9/8/15 Flashcards

1
Q

Describe the structural characteristics of Treponema pallidum.

A

Spiral bacterium

outer membrane with 3 axial fibrils = motility

flexible peptidoglycan cell wall

No LPS

REALLY thin = seen only by darkfield microscopy

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2
Q

List some cultural characteristics of T. pallidum.

A
  • Generation time = 30 hours
  • Doesn’t grow well on artificial media
  • Microaerophilic (3-5% O2)
  • Very sensitive to drying/heat
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3
Q

Describe the transmission of T. pallidum.

A

Intimate sexual contact with infective primary/secondary lesions

Passes thru placenta = congenital infection

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4
Q

Describe primary syphilis infection.

A
  • ulcerative lesion at site of inoculation
  • regional lymphadenopathy
  • painless papule = chancre
  • heals spontaneously

-no systemic manifestations

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5
Q

Describe secondary syphilis infection.

A
  • systemic signs and symptoms
  • flu-like illness (2-10 wks after primary lesion heals)
  • Papulosquamous rash (entire body)
  • Condylomata lata: papules coalesce in moist areas
  • Generalized lymphadenopathy
  • Heals spontaneously but may recur over four years
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6
Q

Describe latent syphilis.

A
  • Positive treponemal serologic test
  • No clinical manifestations
  • Untreated person
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7
Q

What effects are seen in late (tertiary) syphilis infection.

A
  • Neurosyphilis: CNS affected
  • Cardiovascular syphilis: proximal aorta affected (AAA could result)
  • Benign Gummatous syphilis: tumor-like lesions in bone/cartilage
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8
Q

Describe congenital syphilis infection effects.

A
  • Multi-system disease:
  • Rhinitis: purulent discharge = snuffles
  • Rash
  • Bone/cartilage/teeth involved
  • hepatomegaly/spleen enlargement
  • Lymph nodes/CNS affected
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9
Q

Describe changes seen in Neurosyphilis.

A
  • Asymptomatic
  • Meningovascular: chronic meningitis affecting arteries and cranial nerves
  • Paresis: dementia from cortical degeneration
  • Tabes dorsalis: demyelination causing loss of pain and temperature sensation
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10
Q

What 2 microscopic techniques are used to diagnose syphilis?

A
  1. Darkfield: primary/secondary lesions
  2. Direct Fluorescence Antibody Test: monoclonal Abs, material from lesion/biopsy
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11
Q

What are some of the non-treponemal tests for syphilis serology, and how do they work?

A
  • Both use antibodies that are NOT directed agains T. pallidum specifically
  • RPR: Rapid Plasma Reagin = in serum
  • VDRL: Venereal Disease Research Labs = done on CSF
  • False positive tests common
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12
Q

What are some Treponemal Serology tests and how do they work?

A

-Measure specific antibody against T. pallidum

  • FTA-Abs: Fluorescent Treponemal Antibody-Absorption Test (either reactive or non-reactive)
  • TPPA - PA: Particle agglutination
  • EIA/CIA (ELISA): Chemiluminescence immunoassay (high false positive rate)
  • Decrease false positives when confirming RPR assay

THINK: all of these end in “a” = Antibody Against T pallidum

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13
Q

What are the differences between the traditional and the reverse diagnostic algorithms of Syphilis?

A

Traditional: Non-specific to specific test

Reverse: Specific to non-specific to Specific

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14
Q

What are treatment options for Syphilis?

A

–Benzathine Penicillin G (IM) = single dose

Alternate = Tetracycline

–Jarisch-Herxheimer reaction (after treatment)

  • fevers, chills, headache, hypotension
  • Release of toxic products from killed Spirochetes
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15
Q

List general characteristics of Borrelia.

A
  • Larger Spirochetes
  • Mammalian reservoir (spread to humans via tick/louse vectors)
  • Results in Relapsing Fever or Lyme Borreliosis
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16
Q

Describe culture characteristics of B. recurrentis.

A

B. recurrentis: Wright’s Stained Blood Smear: Blood, serum or tissue-containing media

17
Q

Describe antigen diversity in B. recurrentis.

A

Alter antigenic structure during infection

Gene switch from silent to expressed locus (like. N. gonorrheae) on plasmid

Relapse caused by emergence and multiplication of antigenic variants

18
Q

Describe the differences in epidemic and endemic relapsing fever.

A

Epidemic: Louse-borne (no reservoir)

-Times of war and famine (“lousy conditions”)

Endemic: Tick-borne (rodent reservoir)

-Mountain regions of Western US

19
Q

What are the clinical manifestations of Relapsing Fever?

A

Fever

Chills

Mm pain

Headache

RELAPSES (antigenic variation)

20
Q

How is Relapsing fever diagnosed?

A

Blood smear

Serology: cross reactions with other Spirochetes

21
Q

What treatment options are available for Relapsing Fever (B. recurrentis)?

A

-tetracycline, erythromycin

  • Jarisch-Herxheimer reactions common (like Syphilis)
  • fevers, chills, headache, hypotension
22
Q

Describe Lyme Borreliosis.

A

Systemic spirochetal disease resembling syphilis in its stages and prominent involvement of skin and CNS

23
Q

What are the primary reservoirs of Borrelia burgdorferi?

A

Deer and white-footed mouse

24
Q

What is the major vector for Lyme Borreliosis?

A

Tick : Ixodes

25
Q

Describe early stage Lyme Disease.

A
  • Erythema migrans = expanding erythematous lesion at site of tick bite
  • Flu-like illness
26
Q

Describe Early Disseminated Lyme Disease.

A
  • Fatigue
  • Headache
  • Fever
  • Malaise
  • Heart block
  • CNS (CN VII): facial nerve paralysis
  • Arthritis
27
Q

What stage of Lyme Disease is associated with the following symptoms?

  • Arthritis: recurrent, esp knees (with fluid)
  • Encephalopathy: fatigue, memory loss, cog defects
  • Chronic skin condition: acrodermatitis chronica atrophicans
A

Late stage

28
Q

How is Borrelia burgdorferi diagnosed?

A

Serology: ELISA or IFA

-confirm with Western Blot

PCR: skin, synovial fluid, CSF

29
Q

What treatment options are available for Lyme Borreliosis?

A
  • Early: Amoxicillin, doxycycline (oral)
  • Late: Pen G or ceftriaxone (parenteral)
30
Q

What prevention methods are used against Lyme Borreliosis?

A
  • Repellants
  • Tick checks/removal (have to be attached for 24 hours before infection transmitted)
31
Q

What is the epidemiology of Leptospirosis?

A
  • Zoonosis with many animal hosts
  • rodents, dogs, cattle, swine
  • Transmission = ingestion/direct contact with food or water contaminated with infected animal urine
32
Q

Describe the first stage of Leptospirosis.

A
  • Bacteremia (present in blood): first week
  • fever
  • headache
  • myalgia
  • conjunctival suffusion (redness)
  • ab pain
  • vomiting
33
Q

Describe the second stage of Leptospirosis.

A
  • Immune: present only in urine: first month
  • aseptic meningitis
  • generalized illness
  • uveitis (inflammation in eye)
  • rash
  • fever
34
Q

What symptoms are associated with the severe stage of Leptospirosis?

A

-First 2 stages blended: in blood and urine

-prominent hepatitis/jaundice, kidney involvement, hemorrhage

  • low mortality
  • about day 3 onward
35
Q

How are infections cause by Leptospirosis interrogans diagnosed?

A

Culture: blood and CSF (early), urine (late)

Serology: MAT = microscopic agglutination test after first week

36
Q

What are treatment options for Leptospirosis?

A

-penicillin, ceftriaxone, doxycycline

MHD Block III (12 decks)

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