Pediculosis and Syphils

Question 1

pediculus humanus capitis

Answer 1

• scalp, esp behind ears
• egg sac and thinner adult body
• classic presentation is schoolgirls sharing hair accessories
• insecticidal shampoo TWICE- 10 days apart plus nit combing
• hot wash all clothing and linens, check family and classmates
• allergic reactions to louse saliva, secondary staph infection

Question 2

pediculus humanus corporis

Answer 2

• clothing, especially seams
• life cycle
• classic presentation- homeless
• refer for services; improve hygiene
• discard clothing, or wash plus insecticide treatment
• can transmit typhus, trench fever, relapsing fever

Question 3

pthirus pubis

Answer 3

• pubic hair
• looks like a crab
• sexually promiscuous
• shave pubic hair or coat with vaseline
• hot wash all clothing and linens, check partners and children
• marker for other STDs, condoms not protective

Question 4

t. pallidum bacteriology

Answer 4

• small- 0.25 microM diameter means invisible to light microscope
• delicate- can’t survive outside host
• motile- corkscrew motion
• human restricted in nature
• cannot be grown in culture
• extremely infectious sexually
• virulence based on immune evasion

Question 5

t pallidum pathogenesis

Answer 5

• transmitted by sexual contact (acquired), blood, transplacentally (congenital)
• national plan to eliminate in US has hit bumps; working among whites, women, not among man MSM, slowing among minorities

Question 6

acquired t pallidum

Answer 6

• penetrates mucous membranes or small abrasions, grows in blood vessel endothelium, enters lymphatics and bloodstream
• CNS invaded relatively early, though symptoms take years to develop: first CSF abnormalities, then meninges, then parenchyma of brain and spinal cord
• host raises antibodies: specific anti-treponemal and non specific reagin
• immunity is incomplete- surface of spirochete is non-immunogenic, and spirochete downregulates TH1 cells

Question 7

primary syphilis

Answer 7

• painless chancre at site of transmission 3-6 weeks later, highly infectious
• inflammatory infiltrate at site fails to clear organism
• chancre heals 3-12 weeks

Question 8

secondary syphilis

Answer 8

• 4-10 weeks, spirochete multiplication, systemic symptoms
• fever, malaise, myalgias, arthralgias, lymphadenopathy
• mucocutaneous lesions of variable types, condylomata lata, patchy alopecia (moth eaten)
• high antibody titers

Question 9

latent syphilis

Answer 9

• end for 2/3
• organism remains
• secondary symptoms resolve, may return intermittently over the years

Question 10

tertiary syphilis

Answer 10

• 1/3 untreated, fatalities possible
• gummatous syphilis- granulomatous lesions with rubbery necrotic center
• primarily liver, bones, testes
• cardiovascular syphilis- over 10 years- aneurysm of ascending aorta, inflammation of vasa vasorum

Question 11

neurosyphilis

Answer 11

• syphilitic meningitis early (6 mo)
• meningovascular syphilis, damage to blood vessels of meninges, brain, spinal cord
• parenchymal neurosyphilis:
• tabes dorsalis- damage to spinal cord- top of foot loses sensation
• disruption of dorsal roots- loss of pain
• general paresis- damage to cortical brain
• dementia

Question 12

congenital syphilis

Answer 12

• treponemes readily cross placenta and infect fetus
• miscarriage/stillbirth/ neonatal death 40-50%
• within first two years, surviving infants develop severe secondary syphilis

Question 13

syphilis and HIV

Answer 13

• ulcerations of syphilis facilitate HIV infection

- HIV immunosuppression accelerates syphilis course, reduces efficacy of treatment

Question 14

syphilis diagnosis-exam

Answer 14

• the great imitator
• time course of sx- primary 3 weeks
• chancres are raised, red, firm buttonlike structure up to several cm, heal in 4-8 weeks
• not painful unless super infected
• site may be genital or other intimate
• local lymph node swells with invasion

Question 15

exam secondary

Answer 15

• beings 4-10 weeks after primary, peaks 3-4 mo after infection
• may be subtle
• first round rash is bilaterally symmetrical, with generalized non-tender lymphadenopathy, round pink spots, 5-10 mm
• second batch of lesions appears days or weeks later, palms and something necrotic
• patchy alopecia
• condylomata lata
• mild constitutional symptoms- malaise, headache, anorexia, nausea, aching pains in the bones, and fatigue, fever, and neck stiffness
• syphilitic meningitis

Question 16

condylomata lata

Answer 16

• reddish brown papular lesions on the penis or anogenital area
• can coalesce into large elevated plaques up to 2-3 cm diameter
• lesions usually progress from red, painful, and vesicular to gun metal grey
• sometimes confused with venereal warts

Question 17

tertiary syphilis exam

Answer 17

• 3-10 year after infection, years of inflammation
• gumma= bone, deep boring pain worse at night, skin-hyperpigmented circle, often of lowe leg, asymmetric, few grouped close
• liver jaundice
• cardiovascular syphilis, aorta or other major arterial scarring, diastolic murmur with a tambour quality, aortic dilation with insufficiency
• meningovascular syphilis- 5-10 years after infection, endarteritis affects small blood vessels of the meninges, brain, and spinal cord
• CNS vascular insufficiency or stoke
• parenchymal neurosyphilis- 15-20 years after primary infection
• argyll-robertson pupil

Question 18

argyll robertson pupil

Answer 18

• hallmark of neurosyphilis
• one or both pupils fail to constrict in response to light
• but they do constrict to focus on a near obkect

Question 19

imaging for exam

Answer 19

• CT for gummas
• chest radiograph, angiograph for cardiovascular syphilis
• CT and MRI for neurosyphilis
• lumbar puncture for neurosyhilis or syphilis + HIV
• VDRL, cell count, protein
• PCR for evidence of past infection

Question 20

lab diagnosis

Answer 20

• wont culture, too small to gram stain
• swab moist cutaneous lesions for darkfield microscopy or IF
• for neuro, use CSF for tests, specific but not senstitive
• serology- first, non treponemal serology screening using venereal disease research lab (VDRL), rapid plasma reagin (RPR), or ICE syphilis recombinant antigen test

Question 21

VDRL/RPR flocculation assay

Answer 21

• reagin + ox heart extract= aggregates if you have it
• cheap
• easy
• semiquantitative titer decreases with successful treatment

Question 22

lab diagnosis 2

Answer 22

• confirm positive/equivocal results with treponeme specific tests
• fluorescent treponemal antibody absorption
• quantitative VDRL/RPR
• microhemagglutination assay MHA-TP
• t pallidium hemagglutination TPHA
• t pallidum particle agglutination TPPA

Question 23

lab for primary

Answer 23

• dark field

- RPR/VDRL +/-

Question 24

lab for secondary

Answer 24

• RPR, VDRL
• TPPA
• AIA, FTA

Question 25

lab for tertiary

Answer 25

- TPPA, AIA, FTA | - RPR and VDRL +/-

Question 26

histology

Answer 26

- endarteritis caused by binding of spirochetes to endothelial cells mediated by host fibronectin - plasma cell rich infiltrate- delayed hypersensitivity to t pallidum leads eventually to gummatous ulcerations/ necrosis

Question 27

t pallidum treatment

Answer 27

- penicillin- benzathing penecillin G - full panel of STD tests - kills bacterial over weeks of slow release, no known resistance - tertiary/ neuro damage may not heal - congenital, treat mother by month 5, if allergic desensitize her and still treat

Question 28

prevention

Answer 28

- condoms - clean needles - routine serologic screening of pregnant, planning, and post partum women - notification of exposed sexual and drug partners

Question 29

yaws and pinta

Answer 29

-both will give RPR and VDRL pos results

Question 30

yaws

Answer 30

- treponema pertenue - tropical areas of africa, asia, south america, ocean - few thousand cases per year, usually peds - overcrowding and poor sanitation - transmitted by direct contact with skin lesions - multiple stages similar to syphilis, but without neuro/cardio involvement - penicillin G

Question 31

pinta

Answer 31

- treponema carateum - skin lesions, primarily young adults, probably passed by direct contact - very similar to yaws except for hyperpigmentation and restriction to skin- no constitutional symptoms - a few hundred cases/ year in central and south america - entirely human restricted - penicillin G

Question 32

summary 1

Answer 32

- pediculosi is caused by three types of lice - head is schoolkids, itchy behind ears. body is homeless, itchy at night. pubic is promiscuous, itchy groin - diagnose by eye in office, mag glass, microscope - head and pubic nits on hair, body nits onclothes - head and body elongated, pubic wide - treat with 2 rounds of insecticide and nit combing and hot laundering - check close contacts, inform all contacts - pubic- STD panel

Question 33

summary 2

Answer 33

- treponema: - too small to see by standard microscopy, need darkfield - cant be cultured - invade lymphatics and bloodstream right away, no build up - virulence based on immune evasion- low IF - t pallidum transmitted sexually or congenitally, yaws and pinta by direct contact - humans raise mostly useless antibodies, in quantity (reagin) - syphilis has four stage disease- 1 chancre, 2 body wide rashes, condylomata lata, and patchy alopecia, latent period, 3 gummas, neuro, cardiac - neurosyphilis may be meningitis, tabes dorsalis, general paresis, check for argyll robertson pupil - congential syphilis kills 50% fetus/newborn, survivors are infected, bone deformities, interstital keratisis, progress rapidly to symptoms of secondary and tertiary syphilis if untreated - diagnosis depends on assembling accurate timecourse of the many varied symptoms, patient may have ignored early ones that appeared to resolve - labs- VDRL, RPR, confirm exposure with tests for specific antibodies, histo of lesions shows infiltrate - treat with penicillin G