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48 Cards in this Set
- Front
- Back
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What are spirochetes?
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Long, slender, motile, flexible, and undulating G- bacteria that have a characteristic helical shape.
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What are three elements of spirochete structure?
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Cell wall
Axial filaments Protoplasmic cylinder |
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What is the purpose of axial filaments?
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Axial filaments cause the cell to rotate, enabling tissue invasion in a corkscrew manner.
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What are four ways in which spirochetes are identified?
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1) Dark-field microscopy
2) Immunofluorescent stain 3) ELISA 4) Western blot |
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Which method is most sensitive?
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Western blot
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What are three genera of spirochetes that are important human pathogens?
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Treponema
Borrelia Leptospira interrogans |
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What are distinguishing morphological characteristics of each?
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Treponema are tightly wound spirals
Borrelia are large loosely wound irregular coils Septospira are tight spirals with hooked ends |
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What are their oxygen requirements?
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Microaerophilic
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Which Treponema species is a major human pathogen?
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Treponema pallidum
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What does treponema pallidum cause?
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Syphilis
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How is Treponema pallidum transmitted?
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Sexually or transplacentally
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How are the stages of syphilis categorized?
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Primary
Secondary Tertiary stages |
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What are the clinical manifestations of primary syphilis?
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1) Chancre, shallow, indurated, painless ulcers at the site of contact 3-6 weeks postexposure that heal spontaneously.
2) Asymptomatic period (3-24 weeks) with hematogenous/lmphatic spread throughout body. |
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What are the clinical manifestations of secondary syphilis?
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1) Maculopapular rash on palms and soles
2) Condyloma latum 3) Systemic involvement 4) Heals over 6 weeks, then may enter latent phase. |
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What is condyloma lata?
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A moist, erythematous papule in anogenital areas pathognomic of syphilis.
Condyloma latum is caused by T. pallidum Condyloma accuminatum is caused by human papillomavirus |
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What are four clinical anifstations of secondary systemic involvement?
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1) Chorioretinitis
2) Hepatitis 3) Nephritis 4) Meningitis This is why syphilis is called the "great mimic". |
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Why are the clinical manifestations of tertiary syphilis?
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1) Gummas of skin and bones
2) Cardiovascular lesions (aneurysm of ascending aorta) 3) Tabes dorsalis (neurosyphilis) 4) Argyll-Robertson pupil |
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What is tabes dorsalis?
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Damage to teh dorsal root and posterior column resulting in compromised vibration, proprioception, pain, and temperature sensation.
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What is Argyll-Robertson pupil?
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A pupil that constricts to accommodation but not to light.
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What are the clinical manifestations of latent syphilis?
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Absence of symptoms lasting 3-30 years that can ultimately progress to secondary or tertiary syphilis.
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How is syphilis diagnosed?
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Serologically
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Which types of antibodies does syphils elicit?
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Nontreponemal antibodies
Antitreponemal antibodies |
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What are nontreponemal antibodies specific for?
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Phospholipid components of mammalian membranes (cardiolipin).
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What are two examples of nontreponemal antibody tests?
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1) Venereal Disease Research Laboratory (VDRL)
2) Rapid plasma reagent (RPR) VDRL and RPR not specific for T. pallidum. |
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What are antitreponemal antibodies specific for?
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Treponemal surface proteins.
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Clinically, what is the most sensitive diagnostic test for syphilis?
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Flourescent treponemal antibody absorption (FTA-ABS) test which detects human antibodies to treponemes.
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What is first line treatment for syphilis?
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Penicillin, intramuscular (IM) or intravenous (IV).
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What is the Jarisch-Herxheimer reaction?
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Fever
Chills Myalgias Influenza-like symptoms in patients with secondary syphilis lasting up to 12 hours after penicillin administration. |
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What are two pathogenic Borrelia species?
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B. burgdorferi
B. recurrentis |
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Whid diseases do B. burgdorferi adn B. recurrentis cause?
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Lyme disease
Relapsing fever |
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What is the vector for B. burgdorferi?
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Deer tick (Ixodes tick)
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What is the vector for B. recurrentis?
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Human body louse
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How common is Lyme disease?
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Most common tick-borne bacterial disease.
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What is the time course for Lyme disease?
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Stage 1: Days to weeks after tick bite
Stage 2: Weeks to months after tick bite Stage 3: Months to years after tick bite |
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What are the clinical manifestations of Lyme disease stage 1?
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1) Erythema chronica migrans - a clear center surrounded by a spreading circular red rash
2) Flu-like symptoms including fever, chills, fatigue, and headaches. |
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What are the clinical manifestations of Lyme disease stage 2?
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1) Myocarditis or pericarditis
2) Bell's palsy (7th CN palsy) 3) Aseptic meningitis |
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What are the clinical manifestations of Lyme disease stage 3?
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1) Arthritis of the large joints
2) Chronic CNS disease |
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What are the drugs of choice for Lyme disease?
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Doxycycline or amoxicillin
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What component of B. recurrentis causes relapsing fever?
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B. recurrentis surface antigens
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How does the surface antigen of B. recurrentis cause relapsing fever?
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B. recurrentis has the capability to alter surface antigens, making old host antibodies ineffective, thus causing relapses until new antibodies are synthesized?
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What are teh symptoms of relapsing fever?
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Cycle of high fever, headaches, muscle pain, and general malaise followed by 8 days of remission, which repeat up to 10 times.
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What is the treatment for relapsing fever?
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Doxycycline or erythromycin
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What disease is caused by Leptospira interrogans?
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Leptospirosis
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How is leptospirosis transmitted?
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The organism enters water sources via urine of rats, domestic livestock, and pets; humans are infected by drinking or swimming in contaminated water.
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What is the clinical presentation of leptospirosis in Phase 1?
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Symptoms 2 weeks postinfection characterized by a period of fever, chills, headaches, and resolution of symptoms.
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What is the clinical presentation of leptospirosis in Phase 2?
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Symptoms 1 week after resolution characterized by aseptic meningitis, liver damage (jaundice), and impaired kidney function.
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How is leptospirosis diagnosed?
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Phase 1: Culturing blood or CSF
Phase 2: Culturing urine |
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What is the treatment of choice?
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Doxycycline or penicillin G
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