Pediculosis/Syphillis Flashcards
pediculus humanus capitis site and classic presentation
scalp, especially behind the ears. classicly because of school girls sharing hair accessories.
pediculus humanus corporis site and classic presentation
clothing, especially the seams. classic on the homeless.
pthirus pubis site and classic presentation
pubic hair, classic on those who are sexually promiscuous
pediculus humanus capitis treatment of patient and environment
nit combing, hot water laundry, vacuum everything, store all recently used stuffed animals and pillows in plastic bags for 3 weeks. can use insecticide too.
pediculus humanus corporis treatment
discard clothing or wash plus insecticide treatment. improve hygiene. Can transmit typhus, trench fever, and relapsing fever, so watch for those.
pthirus pubis treatment
shave pubic hair. hot wash all linens and clothing, check partners and children. crabs are a marker for other STDs so check.
T. pallidum bacteriology
small, invisible to light microscope. cant survive outside of host. motile using a flagellar corkscrew motion. human restricted in nature, can’t grow in culture, very sexually infectious and virulence is based on immune evasion
t. pallidum pathogenesis
transmitted by sexual contact (acquired), blood, and transplacentally (congenital). national plan to eliminate in the US has hit bumps
acquired t. pallidum pathogenesis
penetrates mucous membranes or small abrasions. grows in blood vessel endothelium, enters lymphatics and bloodstream. CNS is invaded relatively early, though symptoms take years to develop. Host raise antibodies, specific anti-trponemal and nonspecific reagin. Immunity is incomplete since surface of spirochete is nonimmunogenic. spirochete down-regulates TH1 cells
primary syphillis
painless chancre at site of transmission 3-6 weeks later. highly infectious. inflammatory infiltrate at site fails to clear organism. chancre heals in 3-12 weeks.
secondary syphillis
4-10 weeks, spirochete multiplication -> systemic symptoms. fever, malaise, myalgias, arthalgias, lymphadenopathy, mucocutaneous lesions of variable types, condylomata lata, patchy alopecia, high antibody titers
latent syphillis
organism remains, secondary symptoms resolve, may return intermittently over the years. happens to 2/3 of people
tertiary syphillis
happens to 1/3 of people. gummatous syphils: granulomatous lesions with rubbery, necrotic center. primarily in liver, bones, and testes. Cardiovascular syphilis: aneurysm of ascending aorta caused by chronic inflammation of vasa vasorum. neurosyphilis: meningitis early (6 months). Meningovascular syphilis: damage to blood vessels of meninges, brain, and spinal cord. Parenchymal neurosyphilis: tabes dorsalis: damage to spinal cord, leading to impaired sensation and wide gait. Disruption of dorsal roots leads to loss of pain and temp sensation, and areflexia. general paresis leads to damage of cortical brain tissue and dementia
congenital syphilis pathogenesis
treponemes readily cross placenta and infect fetus. miscarriage, stillbirth, and neonatal death 40-50%. within first two years, surviving infants develop severe secondary syphilis.
syphilis and HIV
ulcers from syphilis facilitate HIV infection. HIV immunosuppression accelerates syphilis course, and reduces efficacy of treatment
diagnosing primary syphilis
chancres, raised red and firm buttonlike structure. heal in 4-8 weeks, not painful unless superinfected. site may be genital or other intimate, local lymph node swells with invasion
secondary syphilis diagnosis
begins 4-10 weeks after primary, peaks 3-4 months after infection. may be subtle. first round raash is bilaterally symmetrical, with generalized nontender lymphadenopathy, round pink spots. second batch of lesions appears days or weeks later on palms and soles, become necrotic. Patchy alopecia. condylomata lata: reddish brown papular lesions on penis or anogenital area. can coalesce into large elevated plaques. lesions usually go from red to gray. sometimes confused with genital warts. Mild constitutional symptoms such as headache and malaise, also meningitis
tertiary syphilis diagnosis
3-10 yrs after infection. gumma in bone: deep boring pain worse at night. Skin: hyperpigmented circle. often on lower leg, asymmetric, and few grouped closely. Liver: jaundice.
Cardiovascular syphilis: aorta or other major arterial scarring, diastolic murmur with a tambour quality, secondary to aortic dilation with valvular insufficiency.
meningovascular syph: 5-10 yrs after infection. endarteritis affects small blood vessels of meninges, brain, and spinal cord. CNS vascular insufficiency or stroke.
Parenchymal neurosyph: 15-20 yrs after infection. invasion by t. pallidum. general paretic syph: widespread parenchymal invasion that causes individual cell death and brain atrophy. Tabes dorsalis: damage to sensory nerves in dorsal roots. Deep ulcers on feet, dementia
argyll-robertson pupil
hallmark of neurosyphilis. one or both pupils fail to constrict in response to light, but do constrict to focus on a near object
t. pallidum diagnosis: exam
imaging: CT for gummas, chest xray/angiograph for cardiovasc syph, CT and MRI for neurosyph. Lumbar puncture for neurosyph or syph + HIV. VDRL, cell count, protein, PCR for evidence of past infection
t. pallidum diagnosis: lab
won’t culture, too small to gram stain. swab moist cutaneous lesions for darkfield microscopy or IF. for neurosyph, use CSF for tests. specific but not sensitive. Serology: use venereal disease research laboratory, then rapid plasma reagin, or ice syphilis recombinant antigen test. can confirm positive results with treponeme specific tests: Fluorescent treponemal antibody absorption, quantitative VDRL/RPR, microhemagglutination assay, hemmagglutination, and particle agglutination
t. pallidum histology
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
t. pallidum treatment
penicillin. full panel of STD tests. slow release penicillin. tertiary neuro/cardio damage may not heal. for congenital, treat mother by 5th month of gestation with penicillin. if allergic, use inpatient oral desensitization procedure. can aso use tetracycline, doxycycline, erythromycin, ceftriaxone. much less effective though. follow up bloodwork is necessary
jarisch-herxheimer reaction
8-24 hr after start of treatment, many patients have flulike symptoms or exacerbation of rash. resolves in 24 hours
