Spirochetes Flashcards
what is the diagnostic approach for spirochetes
serologic
what is the causative agent of syphillis
treponema pallidum
treponema pallidum - overview
*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
treponema pallidum (syphillis) - STD ranking
3 most common STD in the US
pathology (target) of treponema pallidum (syphillis)
*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
epidemiology of syphilis
*increasing in men who have sex with men
*increasing congenital infections
*NOT highly contagious
*MOST CONTAGIOUS in EARLY stages
primary syphilis - clinical features
*chancre on penis or vulva/vagina (PAINLESS)
*lesion is teeming with spirochetes
*heals if left untreated
*infects the vaso vasorum
secondary syphilis - clinical features
*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
condyloma lata
warty lesions with high number of spirochetes which appears on mucous membranes (vagina or anus)
*classic s/s of secondary syphilis
latent syphilis
*no clinical manifestations, signs or symptoms
*still with active infection and intermittent bacteremia
*would still test positive if tested
*still infectious
tertiary syphilis - clinical features
*years to decades after primary infection
*TABES DORSALIS (degeneration/demyelination of dorsal column of spinal cord)
*paresis (CNS/brain infection)
*3rd nerve involvement (argyll robertson pupil)
*aortitis
*gumma granulomatous lesions
Argyll Robertson pupil
3rd nerve palsy associated with SYPHILIS: pupil will constrict with accommodation but not react to light (light-near dissociation)
congenital syphilis
*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
syphilis - serology diagnosis
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
treatment of syphilis
PENICILLIN!
*if pregnant women are allergic, we must desensitize the patient to penicillin
what is the vector for Lyme disease
Ixodes scapularis (deer tick)
what is the causative agent of Lyme disease
Borrelia burgdorferi
Borrelia burgdorferi (Lyme disease) - virulence factors
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
lyme borreliosis - early localized clinical manifestations (phase 1)
*erythema migrans (flat rash; RESEMBLES A BULLS EYE)
*fever, malaise, headache, regional adenopathy
lyme borreliosis - early disseminated infection (phase 2)
*several days to weeks after untreated erythema migrans (EM)
*multiple secondary EM-like lesions (smaller)
*fever, malaise, headache, etc
lyme borreliosis - later early disseminated infection (phase 3)
*meningitis/encephalitis
*7th NERVE PALSY!!!
*AV block in the heart
what disease should you associate with 7th nerve palsy
lyme disease
lyme borreliosis - late persistent infection
*months after onset of the tick bites
*arthritis (usually of the knee)
*neurologic disease (encephalomyelitis)
lyme disease - diagnosis
*visualization of erythema migrans (if early enough)
*disseminated or late infection: 2 step serologic testing (ELISA) for antibodies
Southern Tick Associated Rash Illness (STARI)
*borrelia lonestari (in the lone-star tick)
*EM-like lesion
*no systemic, secondary, or long term symptoms identified
treatment of lyme disease
DOXYCYCLINE or ceftriaxone (if later)
Jarisch-Herxheimer Reaction
*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
leptospira interrogans
*tightly coiled spirochete
*shed in urine of infected mammals for weeks/months
*exposure is through surface or flood water
leptospirosis - early clinical manifestations
fever, headache, stiff neck, myalgias, nausea, vomiting
leptospirosis - 2nd phase (Weil’s Disease)
*LIVER DYSFUNCTION
*KIDNEY DYSFUNCTION
*return of primary symptoms
*thrombocytopenia
*pulmonary hemorrhage
leptospirosis - diagnosis
*serology through microscopic agglutination test
*may be negative early in infection
