Pediculosis/Syphillis

Question 1

pediculus humanus capitis site and classic presentation

Answer 1

scalp, especially behind the ears. classicly because of school girls sharing hair accessories.

Question 2

pediculus humanus corporis site and classic presentation

Answer 2

clothing, especially the seams. classic on the homeless.

Question 3

pthirus pubis site and classic presentation

Answer 3

pubic hair, classic on those who are sexually promiscuous

Question 4

pediculus humanus capitis treatment of patient and environment

Answer 4

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.

Question 5

pediculus humanus corporis treatment

Answer 5

discard clothing or wash plus insecticide treatment. improve hygiene. Can transmit typhus, trench fever, and relapsing fever, so watch for those.

Question 6

pthirus pubis treatment

Answer 6

shave pubic hair. hot wash all linens and clothing, check partners and children. crabs are a marker for other STDs so check.

Question 7

T. pallidum bacteriology

Answer 7

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

Question 8

t. pallidum pathogenesis

Answer 8

transmitted by sexual contact (acquired), blood, and transplacentally (congenital). national plan to eliminate in the US has hit bumps

Question 9

acquired t. pallidum pathogenesis

Answer 9

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

Question 10

primary syphillis

Answer 10

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.

Question 11

secondary syphillis

Answer 11

4-10 weeks, spirochete multiplication -> systemic symptoms. fever, malaise, myalgias, arthalgias, lymphadenopathy, mucocutaneous lesions of variable types, condylomata lata, patchy alopecia, high antibody titers

Question 12

latent syphillis

Answer 12

organism remains, secondary symptoms resolve, may return intermittently over the years. happens to 2/3 of people

Question 13

tertiary syphillis

Answer 13

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

Question 14

congenital syphilis pathogenesis

Answer 14

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

Question 15

syphilis and HIV

Answer 15

ulcers from syphilis facilitate HIV infection. HIV immunosuppression accelerates syphilis course, and reduces efficacy of treatment

Question 16

diagnosing primary syphilis

Answer 16

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

Question 17

secondary syphilis diagnosis

Answer 17

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

Question 18

tertiary syphilis diagnosis

Answer 18

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

Question 19

argyll-robertson pupil

Answer 19

hallmark of neurosyphilis. one or both pupils fail to constrict in response to light, but do constrict to focus on a near object

Question 20

t. pallidum diagnosis: exam

Answer 20

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

Question 21

t. pallidum diagnosis: lab

Answer 21

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

Question 22

t. pallidum histology

Answer 22

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 23

t. pallidum treatment

Answer 23

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

Question 24

jarisch-herxheimer reaction

Answer 24

8-24 hr after start of treatment, many patients have flulike symptoms or exacerbation of rash. resolves in 24 hours

Question 25

Yaws

Answer 25

treponema pertenue. tropical areas of africa, asia, south america, oceania. due to overcrowding and poor sanitation. transmitted by direct contact with skin lesions. multiple stages similar to syphilis, but without neuro or cardio involvement. penicillin G treats. RPR and VDRL positive test results

Question 26

pinta

Answer 26

treponema carateum. skin lesions, primarily affects young adults, probably passed by direct contact. similar to yaws except for hyperpigmentation and restriction to skin. south/central america. human restricted. treat w/ penicillin G. RPR and VDRL positive