Spirochetes

Question 1

what is the diagnostic approach for spirochetes

Answer 1

serologic

Question 2

what is the causative agent of syphillis

Answer 2

treponema pallidum

Question 3

treponema pallidum - overview

Answer 3

*causes syphillis
*tightly coiled spirochete
*observed via dark-field microscopy or by direct fluorescent antibody (DFA) testing
*do NOT grow in cell-free cultures
*spread by direct sexual contact

Question 4

treponema pallidum (syphillis) - STD ranking

Answer 4

3 most common STD in the US

Question 5

pathology (target) of treponema pallidum (syphillis)

Answer 5

*causes VASCULITIS and infection of small blood vessels
*includes the VASO VASORUM of large blood vessels (like the aorta)
*a lot of the destruction is due to the immune response and not the pathogen itself

Question 6

epidemiology of syphilis

Answer 6

*increasing in men who have sex with men
*increasing congenital infections
*NOT highly contagious
*MOST CONTAGIOUS in EARLY stages

Question 7

primary syphilis - clinical features

Answer 7

*chancre on penis or vulva/vagina (PAINLESS)
*lesion is teeming with spirochetes
*heals if left untreated
*infects the vaso vasorum

Question 8

secondary syphilis - clinical features

Answer 8

*weeks to a few months after primary infection
*DISSEMINATED INFECTION
*flu-like symptoms (fever, headache, muscle aches)
*subclinical meningitis
*RASH which includes PALMS and SOLES of feet
*condyloma lata

Question 9

condyloma lata

Answer 9

warty lesions with high number of spirochetes which appears on mucous membranes (vagina or anus)
*classic s/s of secondary syphilis

Question 10

latent syphilis

Answer 10

*no clinical manifestations, signs or symptoms
*still with active infection and intermittent bacteremia
*would still test positive if tested
*still infectious

Question 11

tertiary syphilis - clinical features

Answer 11

*years to decades after primary infection
*TABES DORSALIS (dorsal column of spinal cord)
*paresis (CNS/brain infection)
*3rd nerve involvement (argyll robertson pupil)
*aortitis
*gumma granulomatous lesions

Question 12

Argyll Robertson pupil

Answer 12

3rd nerve palsy associated with SYPHILIS
*pupil will accommodate but not react to light)

Question 13

congenital syphilis

Answer 13

*usually a mom with latent syphilis and passes it on to fetus
*if early in pregnancy, fetus loss or malformation
*clinical manifestations:
-Hutchinson teeth, mulberry molars, saddle nose, saber shins uveitis (bowed tibia)
-can also lead to blindness, deafness, cardiovascular disease

Question 14

syphilis - serology diagnosis

Answer 14

1) non-treponema serology (RPR and VDRL):
-look at immune response from host (NOT DIRECTLY FOR ANTIBODY)
-if +, go to test 2:
2) treponema serology (measure IgG antibody)
*FTA-ABS
*TP-PA
-test 2 is a confirmatory test

Question 15

treatment of syphilis

Answer 15

PENICILLIN!
*if pregnant women are allergic, we must desensitize the patient to penicillin

Question 16

what is the vector for Lyme disease

Answer 16

Ixodes scapularis (deer tick)

Question 17

what is the causative agent of Lyme disease

Answer 17

Borrelia burgdorferi

Question 18

Borrelia burgdorferi (Lyme disease) - virulence factors

Answer 18

1) OspA: binds to gut proteins; expression is repressed upon feeding of the tick, allowing the spirochete to migrate to the salivary glands
2) OspC: upregulated once spirochete is in saliva; critical for transmission to mammals

Question 19

lyme borreliosis - early localized clinical manifestations (phase 1)

Answer 19

*erythema migrans (flat rash; RESEMBLES A BULLS EYE)
*fever, malaise, headache, regional adenopathy

Question 20

lyme borreliosis - early disseminated infection (phase 2)

Answer 20

*several days to weeks after untreated erythema migrans (EM)
*multiple secondary EM-like lesions (smaller)
*fever, malaise, headache, etc

Question 21

lyme borreliosis - later early disseminated infection (phase 3)

Answer 21

*meningitis/encephalitis
*7th NERVE PALSY!!!
*AV block in the heart

Question 22

what disease should you associate with 7th nerve palsy

Answer 22

lyme disease

Question 23

lyme borreliosis - late persistent infection

Answer 23

*months after onset of the tick bites
*arthritis (usually of the knee)
*neurologic disease (encephalomyelitis)

Question 24

lyme disease - diagnosis

Answer 24

*visualization of erythema migrans (if early enough)
*disseminated or late infection: 2 step serologic testing (ELISA) for antibodies

Question 25

Southern Tick Associated Rash Illness (STARI)

Answer 25

*borrelia lonestari (in the lone-star tick)
*EM-like lesion
*no systemic, secondary, or long term symptoms identified

Question 26

treatment of lyme disease

Answer 26

DOXYCYCLINE or ceftriaxone (if later)

Question 27

Jarisch-Herxheimer Reaction

Answer 27

*can occur when treating SECONDARY SYPHILIS
*cytokine response to lysis of large number of spirochete organisms
*6-8 hours after tx: shaking chills, fever, hypotension

Question 28

leptospira interrogans

Answer 28

*tightly coiled spirochete
*shed in urine of infected mammals for weeks/months
*exposure is through surface or flood water

Question 29

leptospirosis - early clinical manifestations

Answer 29

fever, headache, stiff neck, myalgias, nausea, vomiting

Question 30

leptospirosis - 2nd phase (Weil’s Disease)

Answer 30

*LIVER DYSFUNCTION
*KIDNEY DYSFUNCTION
*return of primary symptoms
*thrombocytopenia
*pulmonary hemorrhage

Question 31

leptospirosis - diagnosis

Answer 31

*serology through microscopic agglutination test
*may be negative early in infection