Flashcards in Chapter 14: Spirochetes Deck (35):
What are the two unique features of spirochetes compared to other gram-negative bacteria?
(1) surrounded by an additional phospholipid-rich outer membrane with few exposed proteins (make them stealth)
(2)Axial flagella come out of the ends of the cell wall but do not protrude out of the outer membrane. Instead, flagella run sideways along the spirochete under the outer membrane sheath (periplasmic flagella)
How do spirochetes replicate?
What is responsible for the sexually transmitted disease syphilis?
How does treponema pallidum enter the body?
by penetrating intact mucous membranes or invading through epithelial abrasions. skin contact with an ulcer can result in infection
What are the stages of syphilis?
Primary stage: painless ulcer 6 weeks after contact
Secondary stage: 6 wks after 1* chancre healed - Rash on palms and soles, condyloma latum, CNS, eyes, bones, kidneys and/or joints can be involved. Hair loss. Systemic - weight loss, fever, lymphadenopathy. lasts 6 weeks
Latent syphilis: 25% may relapse and develop secondary symptoms again - 4 years
Tertiary stage: gummas of skin and bone, cardiovascular- aneurysm, neurosyphillis
Condyloma latum: painless, wartlike lesion on vulva or scrotum
What is gummatous syphilis?
occurs 3-10 years after primary infection of Treponema pallidum
Localized granulamatous lesions that eventually necrose and become fibrotic
Found mainly in skin(painless with sharp borders) and bones (deep gnawing pain)
What are the 5 most common presentations of neurosyphilis?
Asymptomatic neurosyphilis: CSF tests positive
Subacute meningitis: fever, stiff neck, headache
Meningovascular syphilis: attack circle of Willis -> neurologic impairments
Tabes dorsalis: posterior column and dorsal roots affected --> ataxia and loss of reflexes, pain and temp sensations
General paresis (of the insane): progresive disease of nerve cells in brain
What are the results of the CSF analysis in a pt infected with a bacteria that causes and acute meningitis? Subacute?
Most bacteria cause high neutrophil count, high protein, and low glucose
Trephonema pallidum and mycobacterium tuberculosis cause subacute meningitis with lymphocytes predominating
What is Argyll-Robertson pupil?
Constricts during accommodation but does not react to light
Pt usually has syphilis and may be present in both tabes dorsalis and general paresis
Rule of sixes for syphilis
6 axial filaments
6 week incubation
6 weeks for ulcer to heal
6 weeks after ulcer heals, secondary syphilis develops
6 weeks for secondary syphilis to resolve
66% of latent stage pts have resolution
6 years to develop tertiary syphilis at the least
Effects of syphilis in a fetus of an infected pregnant woman
high mortality rate (stillbirth, spontaneous abortion, neonatal death)
Those that survive will develop early or late congenital syphilis
Does not damage fetus until fourth month of gestation
Early congenital syphilis
Occurs w/i 2 years
like severe adult secondary syphilis
Invasion of nasal mucous membrane -> runny nose snuffles
Lymph node, liver, and spleen enlargement and bone infection (osteitis)
Late congenital syphilis
Similar to adult tertiary syphilis except cardiovascuar involvement rarely occurs
Neurosyphilis is the same, CN8 deafness
Bone and teeth frequently involved: saddle nose and saber shins, Hutchinson's teeth, mulberry molars
Eye disease: corneal inflammation
What can pts with syphilis develop immediately after antibiotics are started?
Mild fever, chills, malaise, headache, and muscle aches
Killed organisms release pyrogen
What do the 3 subspecies of Treponema pallidum general cause?
Skin ulcers and gummas of skin and bones in CHILDREN (exception - carateum only causes skin discoloration)
Do not cause sexually transmitted disease syphyilis
Stages: 1* skin ulcer-->widespread skin lesions-->gummas of bone and skin but no heart of CNS involvement
Endemicum, pertenue, and carateum
What does treponema pallidum subspecies endemicum cause?
endemic syphilis in desert zones of Africa and Middle east
Sharing drinking and eating utensils
Skin lesions in oral mucosa and are similar to condyloma lata of secondary syphilis
Gummas may develop later
What does Treponema pallidum subspecies pertenue cause?
yaws - moist tropics
Person-person via open ulcers
papule grows over months becoming wartlike (mother yaw)
Secondary lesions appear on exposed parts of body
Gummas develop years later
What does Treponema pallidum subspecies carateum cause?
Pinta - purely a skin disease limited to rural Latin America
Direct contact - initial papule slowly expands
Secondary eruption of numerous red lesions that turn blue in the sun!!!!
Lesons become depigmented/white in a year
What causes Lyme disease and relapsing fever?
Borrelia transmitted by insects
What nonspecific tests are used for syphilis? Specific tests?
non-specific treponemal tests VDRL; RPR
Specific treponemal test: FTA-ABS, MHA-TP
What is the most commonly reported tick-borne illness in the U.S? What is it caused by?
Northeast, Midwest and northwestern U.S
Lyme disease and Syphyllis is caused by what type of bacteria?
What are the stages of Lyme disease?
(1) early localized stage: Erythema chronicum migrans
(2) Early disseminated stage: multiple smaller ECM, Neurologic and cardiac and joint involvement
(3) Late stage: chronic arthritis, encephalopathy
What are a pts symptoms during the early localized stage of lyme disease?
10 days after tick bite
Skin lesion - ECM along with flu-like illness anf regional lymphadenopathy
ECM - flat round rash that spreads out over time that has a bright red outer border and the center will clear, turn blue or necrose
Last 4 weeks
What are a pts symptoms during the Early disseminated stage of lyme disease?
stage can occur after or at the same time as first stage
Skin: multiple smaller ECM
Nervous system: aseptic meningitis, cranial nerve palsies, pheripheral neuropathies
Heart: AV nodal block most common, myocarditis (less common)
Joint: brief attacks of arthritis of large joints
What are the pts symptoms during the Late stage lyme disease?
10% of untreated pts develop chronic arthritis that lasts for more than a year
1 or 2 of the large peripheral joints (knee)
B-cell allo antigens?
Can lead to neurologic damage - encephalopathy (memory impairment, irritability and somnolence)
How is Lyme disease diagnosed?
leading edge of rash biopsied and cultured
CSF very difficult
Levels of anti-Borrelia burgdorferi abs often helpful (ELISA and Western blotting)
What causes relapsing fever?
Borrelia recurrentis via body louse
Other Borrelia species via tick (Ornithodoros, western U.S)
What are the symptoms of relapsing fever?
Once in the blood, high fever develops, with chills, headaches and muscle aches
Rash and meningeal involvement may follow
Drenching sweats, fever and symptoms resolve after a week
Afebrile for another week then it relapses
What is the key to relapsing fever??
Abs form and bind specifically to the Borrelia surface proteins and remove it from the blood
But Borrelia rapidly changes surface proteins so Abs cant recognize
New set of Abs formed and Borrelia changes again
How is relapsing fever diagnosed?
Drawing blood during febrile periods only
wright's or Giemsa-stained smear
What are Leptospira?
Long, thin aerobic spirochetes, tight coil with hook on one or both ends
Leptospira interrogans cause human disease: penetrate abraded skin or mucous membranes (swimmin in contaminated water)
Found all over the world in urine of dogs, rats, livestock and wild animals
What are the two phases of Leptospira?
(1) Leptospiremic phase: invade the blood and CSF, abrupt onset of high spiking temperatures, headache, malaise, and sever muscle aches (thighs and lower back), conjunctive red and phtophobia; after 1 week short afebrile period then symptoms recur
(2) Immune phase: IgM antibodies, pts may develop meningismus, CSF reveals elevated white cell count in most pts
What does Leptospira interrogans (serogroup icterohaemorrhagiae) cuase?
Weil's disease - infectious jaundice
Renal failure, hepatitis with jaundice, mental status changes, hemorrhage in many organs